Congratulations to Jordan on his successful PhD viva!

19 January 2024

Congratulations to Jordan for passing his PhD viva at the University of Birmingham. Jordan has been a member of the group since 2019. We are so proud of him, and we wish him all the best in his postdoc at the University of Southampton!

Hrishit Banerjee published an article in Physical Review B

17 October 2023

Using ab initio dynamical mean-field theory we explore the electronic and magnetic states of layered LixMnO2 as a function of x, the state-of-charge. We observe a crossover from coherent to incoherent behavior on delithiation as function of state-of-charge.

Full Article

Congratulations to Matt on his successful PhD viva!

15 October 2023

Sincerest congratulations to Matt for passing his PhD viva at the University of Cambridge! Matt has been an integral part of the group, developing tools we still use to this day. We are proud of his many achievements during his time with us, and we wish him all the best in his future endeavors!

Annalena Genreith-Schriever and Hrishit Banerjee published an article in Joule

19 July 2023

Ni-rich lithium-ion cathode materials achieve both high voltages and capacities but are prone to structural instabilities and oxygen loss. The origin of the instability lies in the pronounced oxidation of O during delithiation: for LiNiO2, NiO2, and the rock salt NiO, density functional theory and dynamical mean-field theory calculations based on maximally localized Wannier functions yield a Ni charge state of ca. +2, with O varying between −2 (NiO), −1.5 (LiNiO2), and −1 (NiO2). Calculated X-ray spectroscopy Ni K and O K-edge spectra agree well with experimental spectra. Using ab initio molecular dynamics simulations, we observe loss of oxygen from the (012) surface of delithiated LiNiO2, two surface O⋅ radicals combining to form a peroxide ion, and the peroxide ion being oxidized to form O2, leaving behind two O vacancies and two O2− ions. Preferential release of 1O2 is dictated via the singlet ground state of the peroxide ion and spin conservation.

Full Article

Welcome Dr Chandan Kumar Singh

22 May 2023

A warm welcome to Dr Chandan Kumar Singh, a post-doctoral research fellow whose research focuses on studying correlated disorders and their impact on complex magnetic structures in various quantum materials.

Angela Harper published an article in AIP Advances

12 May 2023

By including phonon-assisted transitions within plane-wave density functional theory methods for calculating the x-ray absorption spectrum (XAS), we obtain the Al K-edge XAS at 300 K for two crystalline Al2O3 phases. The 300 K XAS reproduces the pre-edge peak for α-Al2O3, which is not visible at the static lattice level of approximation. Configurations from Monte Carlo sampling of the γ-Al2O3 phase space at the 300 K XAS correctly describe two out of the three experimental peaks. We show that the second peak arises from 1s to mixed s-p transitions and is absent in the 0 K XAS. This letter serves as an insight into the electronic origins of the characteristic peaks in the Al K-edge XAS for alumina crystals. Full Article

James Darby published an article in the Journal of the American Chemical Society

31 January 2023

First-principles crystal structure prediction (CSP) is the most powerful approach for materials discovery, enabling the prediction and evaluation of properties of new solid phases based only on a diagram of their underlying components. Here, we present the first CSP-based discovery of metal–organic frameworks (MOFs), offering a broader alternative to conventional techniques, which rely on geometry, intuition, and experimental screening. Phase landscapes were calculated for three systems involving flexible Cu(II) nodes, which could adopt a potentially limitless number of network topologies and are not amenable to conventional MOF design. The CSP procedure was validated experimentally through the synthesis of materials whose structures perfectly matched those found among the lowest-energy calculated structures and whose relevant properties, such as combustion energies, could immediately be evaluated from CSP-derived structures.

Full Article

Andrea Iliceto published an article in the Journal of the American Chemical Society

10 January 2023

Metal–organic magnets (MOMs), modular magnetic materials where metal atoms are connected by organic linkers, are promising candidates for next-generation quantum technologies. MOMs readily form low-dimensional structures and so are ideal systems to realize physical examples of key quantum models, including the Haldane phase, where a topological excitation gap occurs in integer-spin antiferromagnetic (AFM) chains. Thus, far the Haldane phase has only been identified for S = 1, with S ≥ 2 still unrealized because the larger spin imposes more stringent requirements on the magnetic interactions. Here, we report the structure and magnetic properties of CrCl2(pym) (pym = pyrimidine), a new quasi-1D S = 2 AFM MOM. We show, using X-ray and neutron diffraction, bulk property measurements, density-functional theory calculations, and inelastic neutron spectroscopy (INS), that CrCl2(pym) consists of AFM CrCl2 spin chains (J1 = −1.13(4) meV) which are weakly ferromagnetically coupled through bridging pym (J2 = 0.10(2) meV), with easy-axis anisotropy (D = −0.15(3) meV). We find that, although small compared to J1, these additional interactions are sufficient to prevent observation of the Haldane phase in this material. Nevertheless, the proximity to the Haldane phase together with the modularity of MOMs suggests that layered Cr(II) MOMs are a promising family to search for the elusive S = 2 Haldane phase. Full Article

Angela Harper published an article in Chemical Science

21 December 2022

Understanding a material’s electronic structure is crucial to the development of many functional devices from semiconductors to solar cells and Li-ion batteries. A material’s properties, including electronic structure, are dependent on the arrangement of its atoms. However, structure determination (the process of uncovering the atomic arrangement), is impeded, both experimentally and computationally, by disorder. The lack of a verifiable atomic model presents a huge challenge when designing functional amorphous materials. Such materials may be characterised through their local atomic environments using, for example, solid-state NMR and XAS. By using these two spectroscopy methods to inform the sampling of configurations from ab initio molecular dynamics we devise and validate an amorphous model, choosing amorphous alumina to illustrate the approach due to its wide range of technological uses. Our model predicts two distinct geometric environments of AlO5 coordination polyhedra and determines the origin of the pre-edge features in the Al K-edge XAS. From our model we construct an average electronic density of states for amorphous alumina, and identify localized states at the conduction band minimum (CBM). We show that the presence of a pre-edge peak in the XAS is a result of transitions from the Al 1s to Al 3s states at the CBM. Deconvoluting this XAS by coordination geometry reveals contributions from both AlO4 and AlO5 geometries at the CBM give rise to the pre-edge, which provides insight into the role of AlO5 in the electronic structure of alumina. This work represents an important advance within the field of solid-state amorphous modelling, providing a method for developing amorphous models through the comparison of experimental and computationally derived spectra, which may then be used to determine the electronic structure of amorphous materials.

Full Article

Congratulations to Angela on her successful PhD viva!

30 August 2022

Sincere congratulations to Angela for passing her PhD viva at the University of Cambridge! Having been part of the Morris Group since her MPhil, we are all so proud of her many achievements during her time in the group. We all wish her the very best in her future career!

Dr Hrishit Banerjee receives the Poster Commendation Award at the Psi-k 2022 conference

25 August 2022

Congratulations to Hrishit for receiving the Poster Commendation award at the Psi-k 2022 conference for the poster “The importance of electronic correlations in exploring the exotic phase diagram of Li ion battery cathodes”, as part of the symposium C2 dedicated to Functional materials and devices.

New article in Chemistry of Materials

01 August 2022

K-ion batteries (KIBs) have the potential to offer a cheaper alternative to Li-ion batteries (LIBs) using widely abundant materials. Conversion/alloying anodes have high theoretical capacities in KIBs, but it is believed that electrode damage from volume expansion and phase segregation by the accommodation of large K-ions leads to capacity loss during electrochemical cycling. To date, the exact phase transformations that occur during potassiation and depotassiation of conversion/alloying anodes are relatively unexplored. In this work, we synthesize two distinct compositions of tin phosphides, Sn4P3 and SnP3, and compare their conversion/alloying mechanisms with solid-state nuclear magnetic resonance (SSNMR) spectroscopy, powder X-ray diffraction (XRD), and density functional theory (DFT) calculations. Ex situ31P and 119Sn SSNMR analyses reveal that while both Sn4P3 and SnP3 exhibit phase separation of elemental P and the formation of KSnP-type environments (which are predicted to be stable based on DFT calculations) during potassiation, only Sn4P3 produces metallic Sn as a byproduct. In both anode materials, K reacts with elemental P to form K-rich compounds containing isolated P sites that resemble K3P but K does not alloy with Sn during potassiation of Sn4P3. During charge, K is only fully removed from the K3P-type structures, suggesting that the formation of ternary regions in the anode and phase separation contribute to capacity loss upon reaction of K with tin phosphides. Full Article

Congratulations Professor Andrew Morris

01 August 2022

Andrew thanks his research group and all his collaborators on his promotion to Professor of Computational Physics.

Pre-print now available on ArXiv

28 June 2022

Finite Temperature Effects on the X-ray Absorption Spectra of Crystalline Aluminas from First Principles - Angela F. Harper, Bartomeu Monserrat, and Andrew J. Morris Full Article

Angela Harper on joint 3rd-place CoSeC Impact Award 2021

08 October 2021

Angela Harper won joint 3rd-place for her work on bringing the computational expertise of theoretical physicists using atomistic modelling methods and software developed within the CCP in Electronic Structure (CCP9), to not only experimental chemists, but to the wider community. This accelerates both discovery and identification of industrially relevant and new materials using computational methods, thereby reducing the costs, energy and time involved in conducting large-scale experimental studies. CoSeC Casestudy

Andrew published an article in ACS Publications

08 October 2021

One-dimensional (1D) atomic chains of CsI were previously reported in double-walled carbon nanotubes with ∼0.8 nm inner diameter. Here, we demonstrate that, while 1D CsI chains form within narrow ∼0.73 nm diameter single-walled carbon nanotubes (SWCNTs), wider SWCNT tubules (∼0.8–1.1 nm) promote the formation of helical chains of CsI 2 × 1 atoms in cross-section. These CsI helices create complementary oval distortions in encapsulating SWCNTs with highly strained helices formed from strained Cs2I2 parallelogram units in narrow tubes to lower strain Cs2I2 units in wider tubes. The observed structural changes and charge distribution were analyzed by density-functional theory and Bader analysis. CsI chains also produce conformation-selective changes to the electronic structure and optical properties of the encapsulating tubules. The observed defects are an interesting variation from defects commonly observed in alkali halides as these are normally associated with the Schottky and Frenkel type. The energetics of CsI 2 × 1 helix formation in SWCNTs suggests how these could be controllably formed. Full Article

Chris Owen joins the group

01 October 2021

A warm welcome to Chris Owen, a former Nuclear Engineering student (MEng) at the University of Birmingham, now starting his PhD.

Mario Antonio Ongkiko joins the group

01 October 2021

A big welcome to Mario Antonio Ongkiko, a new PhD student under the EPSRC Centre for Doctoral Training in Topological Design.

Matthew Evans published an article in Scientific Data

12 August 2021

The Open Databases Integration for Materials Design (OPTIMADE) consortium has designed a universal application programming interface (API) to make materials databases accessible and interoperable. We outline the first stable release of the specification, v1.0, which is already supported by many leading databases and several software packages. We illustrate the advantages of the OPTIMADE API through worked examples on each of the public materials databases that support the full API specification. Full Article

Chris Owen receives the Rollason Memorial Prize

21 July 2021

Congratulations to Chris Owen for receives the Rollason Memorial Prize for highest mark in the final year project 2020/21. The prize was awarded for his work on ‘Modelling an Amorphous Zirconia ALD Coating using Density-Functional Theory’.

Congratulations to Can Koçer for passing his PhD viva!

09 June 2021

Congratulations to Dr Can Koçer for passing his PhD viva on 9 June, 2021. During his PhD journey, Can published multiple computational research articles, including excellent work on the lithium insertion mechanism of crystallographic shear phases, which all led to a successful completion of his PhD. We wish him all the best in his future career, to be filled with success, bright experiences and new accomplishments.

Angela discusses how to use computational physics to study Li-ion batteries at CamFest

04 April 2021

As part of the 2021 virtual CamFest, Angela submitted a video explanation for the general public about how she uses computational physics to study Li-ion batteries as part of her PhD.

Full Video

Welcome Dr Hrishit Banerjee

01 April 2021

A warm welcome to Dr Hrishit Banerjee, a post-doctoral Research Associate whose research focuses on understanding the physics involved in the degradation of Li-ion batteries.

Congratulations to Jordan Dorrell for receiving the best poster prize at MCCM 2021!

07 January 2021

Jordan Dorrell was awarded the Midlands Computational Chemistry Meeting 2021 best poster prize. Jordan presented a poster titled “Machine Learning Random Structure Searching for Li-Ni-S Cathode Discovery”.

Congratulations to James Darby for passing his PhD viva!!

12 November 2020

The biggest congratulations to Dr. James “Big Jim” Darby for passing his PhD viva, everyone in the group is incredibly excited for him. During his PhD, James worked on refining his skills in coffee art using the TCM Coffee Machine, until it was shut down in March of 2020. After that, he turned his focus to writing up his PhD thesis, which he successfully defended on November 12th 2020. Now, he will be working in the group of Gabor Csanyi, on machine learned atomistic potentials. Congratulations again Big Jim, hoping to celebrate in person in the future soon!

A sample of James’ later work. (2019) Coffee

James, playing tennis, one of his favourite pasttimes, besides simulating tennis match outcomes. (2018) tennis

Matthew Evans published Matador in the Journal of Open Source Software

27 October 2020

The properties of materials depend heavily on their atomistic structure; knowledge of the possible stable atomic configurations that define a material is required to understand the performance of many technologically and ecologically relevant devices, such as those used for energy storage (A. F. Harper et al., 2020; Marbella et al., 2018). First-principles crystal structure prediction (CSP) is the art of finding these stable configurations using only quantum mechanics (A. F. Harper, Evans, et al., 2020). Density-functional theory (DFT) is a ubiquitous theoretical framework for finding approximate solutions to quantum mechanics; calculations using a modern DFT package are sufficiently robust and accurate that insight into real materials can be readily obtained. The computationally intensive work is performed by well-established, low-level software packages, such as CASTEP (Clark et al., 2005) or Quantum Espresso (Giannozzi et al., 2009), which are able to make use of modern highperformance computers. In order to use these codes easily, reliably and reproducibly, many high-level libraries have been developed to create, curate and manipulate the calculations from these low-level workhorses; matador is one such framework.

Full Article

Angela Harper published an article in Chemistry of Materials

25 June 2020

Using first principles structure searching with density-functional theory (DFT) we identify a novel Fm-3m phase of Cu2P and two low-lying metastable structures, an I-43d–Cu3P phase, and a Cm–Cu3P11 phase. The computed pair distribution function of the novel Cm–Cu3P11 phase shows its structural similarity to the experimentally identified Cm–Cu2P7 phase. The relative stability of all Cu–P phases at finite temperatures is determined by calculating the Gibbs free energy using vibrational effects from phonon modes at 0 K. From this, a finite-temperature convex hull is created, on which Fm-3m–Cu2P is dynamically stable and the Cu3−xP (x < 1) defect phase Cmc21–Cu8P3 remains metastable (within 20 meV/atom of the convex hull) across a temperature range from 0 K to 600 K. Both CuP2 and Cu3P exhibit theoretical gravimetric capacities higher than contemporary graphite anodes for Li-ion batteries; the predicted Cu2P phase has a theoretical gravimetric capacity of 508 mAh/g as a Li-ion battery electrode, greater than both Cu3P (363 mAh/g) and graphite (372 mAh/g). Cu2P is also predicted to be both non-magnetic and metallic, which should promote efficient electron transfer in the anode. Cu2P’s favorable properties as a metallic, high-capacity material suggest its use as a future conversion anode for Li-ion batteries; with a volume expansion of 99 % during complete cycling, Cu2P anodes could be more durable than other conversion anodes in the Cu–P system with volume expansions greater than 150 %. The structures and figures presented in this paper, and the code used to generate them, can be interactively explored online using Binder.

Full Article

Can Koçer published an article in the Journal of the American Chemical Society

12 June 2020

Complex crystal structures with subtle atomic-scale details are now routinely solved using complementary tools such as X-ray and/or neutron scattering combined with electron diffraction and imaging. Identifying unambiguous atomic models for oxyfluorides, needed for materials design and structure–property control, is often still a considerable challenge despite their advantageous optical responses and applications in energy storage systems. In this work, NMR crystallography and single-crystal X-ray diffraction are combined for the complete structure solution of three new compounds featuring a rare triangular early transition metal oxyfluoride cluster, [Mo3O4F9]5–. After framework identification by single-crystal X-ray diffraction, 1D and 2D solid-state 19F NMR spectroscopy supported by ab initio calculations are used to solve the structures of K5[Mo3O4F9]·3H2O (1), K5[Mo3O4F9]·2H2O (2), and K16[Mo3O4F9]2[TiF6]3·2H2O (3) and to assign the nine distinct fluorine sites in the oxyfluoride clusters. Furthermore, 19F NMR identifies selective fluorine dynamics in K16[Mo3O4F9]2[TiF6]3·2H2O. These dual scattering and spectroscopy methods are used to demonstrate the generality and sensitivity of 19F shielding to small changes in bond length, on the order of 0.01 Å or less, even in the presence of hydrogen bonding, metal–metal bonding, and electrostatic interactions. Starting from the structure models, the nature of chemical bonding in the molybdates is explained by molecular orbital theory and electronic structure calculations. The average Mo–Mo distance of 2.505 Å and diamagnetism in 1, 2, and 3 are attributed to a metal–metal bond order of unity along with a 1a21e4 electronic ground state configuration for the [Mo3O4F9]5− cluster, leading to a rare trimeric spin singlet involving d2 Mo4+ ions. The approach to structure solution and bonding analysis is a powerful strategy for understanding the structures and chemical properties of complex fluorides and oxyfluorides.

Full Article

James Darby published a new structure prediction method WAM in Chemistry of Materials

02 June 2020

Metal-organic frameworks (MOFs) have emerged as highly versatile materials with applications in gas storage and separation, solar light energy harvesting and photocatalysis. The design of new MOFs, however, has been hampered by the lack of computational methods for ab initio MOF structure prediction, which could be used to inspire and direct experimental synthesis. Here, we report the first ab initio method for the prediction of MOF structures and test it against a diverse set of known MOFs that were chosen for their differences in topology, metal coordination geometry, and ligand binding sites. In all cases, our calculations produced structures that match experiment using only the target composition and ligand molecular structure, proving the versatility of our procedure. The herein presented methodology utilizes the point group symmetry of ligands to enable, for the first time, prediction of MOF structures from first principles, without having to resort to empirical guidelines based on rigid connectivity of nodes and linkers, or to previously determined crystal structures and topologies of known MOFs. This advance provides the first tool to change MOF design from an empirically based process that is based on chemistʼs intuition rooted in literature- or database-established knowledge of node-and-linker connectivity to a more general and theory-driven materials development. This ab initio MOF structure prediction approach, which is here validated on a range of known MOF classes, provides a unique opportunity to explore the phase landscape of MOFs computationally and enables MOF research and development even in case of limited access to laboratory resources, as for example in case of a global pandemic.

Full Article

Can Kocer published as an ACS Editors Choice article in Chemistry of Materials

26 April 2020

Niobium tungsten oxides with crystallographic shear structures form a promising class of high-rate Li-ion anode materials. Lithium diffusion within these materials is studied in this work using density functional theory calculations, specifically nudged elastic band calculations and ab initio molecular dynamics simulations. Lithium diffusion is found to occur through jumps between 4-fold coordinated window sites with low activation barriers (80–300 meV) and is constrained to be effectively one-dimensional by the crystallographic shear planes of the structures. We identify a number of other processes, including rattling motions with barriers on the order of the thermal energy at room temperature, and intermediate barrier hops between 4-fold and 5-fold coordinated lithium sites. We demonstrate differences regarding diffusion pathways between different cavity types; within the ReO3-like block units of the structures, cavities at the corners and edges host more isolated diffusion tunnels than those in the interior. Diffusion coefficients are found to be in the range of 10–12 to 10–11 m2 s–1 for lithium concentrations of 0.5 Li/TM. Overall, the results provide a complete picture of the diffusion mechanism in niobium tungsten oxide shear structures, and the structure–property relationships identified in this work can be generalized to the entire family of crystallographic shear phases.

Full Article - One of the top 20 most downloaded articles in April in Chemistry of Materials.

News Article - A news article has been written on this publication.

Angela Harper publishes review with the group in Johnson Matthey Technology Review

06 March 2020

Portable electronic devices, electric vehicles and stationary energy storage applications, which encourage carbon-neutral energy alternatives, are driving demand for batteries that have concurrently higher energy densities, faster charging rates, safer operation and lower prices. These demands can no longer be met by incrementally improving existing technologies but require the discovery of new materials with exceptional properties. Experimental materials discovery is both expensive and time consuming: before the efficacy of a new battery material can be assessed, its synthesis and stability must be well-understood. Computational materials modelling can expedite this process by predicting novel materials, both in stand-alone theoretical calculations and in tandem with experiments. In this review, we describe a materials discovery framework based on density functional theory (DFT) to predict the properties of electrode and solid-electrolyte materials and validate these predictions experimentally. First, we discuss crystal structure prediction using the ab initio random structure searching (AIRSS) method. Next, we describe how DFT results allow us to predict which phases form during electrode cycling, as well as the electrode voltage profile and maximum theoretical capacity. We go on to explain how DFT can be used to simulate experimentally measurable properties such as nuclear magnetic resonance (NMR) spectra and ionic conductivities. We illustrate the described workflow with multiple experimentally validated examples: materials for lithium-ion and sodium-ion anodes and lithium-ion solid electrolytes. These examples highlight the power of combining computation with experiment to advance battery materials research.

Full Article

Bora Karasulu publishes new paper in JACS

14 February 2020

Li7La3Zr2O12 (LLZO) garnets are among the most promising solid electrolytes for next-generation all-solid-state Li-ion battery applications due to their high stabilities and ionic conductivities. To help determine the influence of different supervalent dopants on the crystal structure and site preferences, we combine solid-state 17O, 27Al, and 71Ga magic angle spinning (MAS) NMR spectroscopy and density-functional theory (DFT) calculations. DFT-based defect configuration analysis for the undoped and Al and/or Ga-doped LLZO variants uncovers an interplay between the local network of atoms and the observed NMR signals. Specifically, the two characteristic features observed in both 27Al and 71Ga NMR spectra result from both the deviations in the polyhedral coordination/site-symmetry within the 4-fold coordinated Li1/24d sites (rather than the doping of the other Li2/96h or La sites) and with the number of occupied adjacent Li2 sites that share oxygen atoms with these dopant sites. The sharp 27Al and 71Ga resonances arise from dopants located at a highly symmetric tetrahedral 24d site with four corner-sharing LiO4 neighbors, whereas the broader features originate from highly distorted dopant sites with fewer or no immediate LiO4 neighbors. A correlation between the size of the 27Al/71Ga quadrupolar coupling and the distortion of the doping sites (viz. XO4/XO5/XO6 with X = {Al/Ga}) is established. 17O MAS NMR spectra for these systems provide insights into the oxygen connectivity network: 17O signals originating from the dopant-coordinating oxygens are resolved and used for further characterization of the microenvironments at the dopant and other sites.

Full Article

Andrew's collaboration with the Friscic group at McGill published in Nature Communications and featured in Quebec Science

15 January 2020

The Nature Communications publication “Halogen-bonded cocrystallization with phosphorus, arsenic and antimony acceptors” Full Article was featured in an article by Quebec Science on the “Formation of bonds between heavy molecules” Full Article. This work on co-crystals with pnictogen-halogen bonds show that these bonds are strong enough to enable co-crystallisation, thereby paving the way for further research in this field.

Angela featured in a Women in STEM interview with the University of Cambridge

10 January 2020

Angela Harper is a PhD candidate at the Cavendish Laboratory, a member of Churchill College, and a Gates Cambridge Scholar. Here, she tells us about her work in renewable energy, setting up a Girls in STEM programme while she was an undergraduate in North Carolina, and the importance of role models when pursuing a career in STEM.

Full Article

New Publication with Can and Andrew in the Journal of the American Chemical Society

01 November 2019

TiNb2O7 is a Wadsley–Roth phase with a crystallographic shear structure and is a promising candidate for high-rate lithium ion energy storage. The fundamental aspects of the lithium insertion mechanism and conduction in TiNb2O7, however, are not well-characterized. Herein, experimental and computational insights are combined to understand the inherent properties of bulk TiNb2O7. The results show an increase in electronic conductivity of seven orders of magnitude upon lithiation and indicate that electrons exhibit both localized and delocalized character, with a maximum Curie constant and Li NMR paramagnetic shift near a composition of Li0.60TiNb2O7. Square-planar or distorted-five-coordinate lithium sites are calculated to invert between thermodynamic minima or transition states. Lithium diffusion in the single-redox region (i.e., x ≤ 3 in LixTiNb2O7) is rapid with low activation barriers from NMR and DLi = 10–11 m2 s–1 at the temperature of the observed T1 minima of 525–650 K for x ≥ 0.75. DFT calculations predict that ionic diffusion, like electronic conduction, is anisotropic with activation barriers for lithium hopping of 100–200 meV down the tunnels but ca. 700–1000 meV across the blocks. Lithium mobility is hindered in the multiredox region (i.e., x > 3 in LixTiNb2O7), related to a transition from interstitial-mediated to vacancy-mediated diffusion. Overall, lithium insertion leads to effective n-type self-doping of TiNb2O7 and high-rate conduction, while ionic motion is eventually hindered at high lithiation. Transition-state searching with beyond Li chemistries (Na+, K+, Mg2+) in TiNb2O7 reveals high diffusion barriers of 1–3 eV, indicating that this structure is specifically suited to Li+ mobility.

Full Article

New Publication by Can in the Journal of the American Chemical Society

13 September 2019

Wadsley–Roth crystallographic shear phases form a family of compounds that have attracted attention due to their excellent performance as lithium-ion battery electrodes. The complex crystallographic structure of these materials poses a challenge for first-principles computational modeling and hinders the understanding of their structural, electronic and dynamic properties. In this article, we study three different niobium–tungsten oxide crystallographic shear phases (Nb12WO33, Nb14W3O44, Nb16W5O55) using an enumeration-based approach and first-principles density-functional theory calculations. We report common principles governing the cation disorder, lithium insertion mechanism, and electronic structure of these materials. Tungsten preferentially occupies tetrahedral and block-central sites within the block-type crystal structures, and the local structure of the materials depends on the cation configuration. The lithium insertion proceeds via a three-step mechanism, associated with an anisotropic evolution of the host lattice. Our calculations reveal an important connection between long-range and local structural changes: in the second step of the mechanism, the removal of local structural distortions leads to the contraction of the lattice along specific crystallographic directions, buffering the volume expansion of the material. Niobium–tungsten oxide shear structures host small amounts of localized electrons during initial lithium insertion due to the confining effect of the blocks, but quickly become metallic upon further lithiation. We argue that the combination of local, long-range, and electronic structural evolution over the course of lithiation is beneficial to the performance of these materials as battery electrodes. The mechanistic principles we establish arise from the compound-independent crystallographic shear structure and are therefore likely to apply to niobium–titanium oxide or pure niobium oxide crystallographic shear phases.

Full Article

Dr. Wataru Sekine joins the group

17 May 2019

Dr. Wataru Sekine will be joining the Morris group for a year. He is from the Murata Manufacturing Co. Ltd. in Japan.

New Publication in Chemistry of Materials on Zeolitic Imidazolate Frameworks

29 April 2019

Abstract: The prediction of topological preferences and polymorph stability remains a challenge for the design of metal-organic frameworks (MOFs) exhibiting a rich topological landscape, such as zeolitic imidazolate frameworks (ZIFs). Here, we have used mechanochemical screening and calorimetry to test the ability of dispersion-corrected periodic density functional theory (DFT) to accurately survey the topological landscape, as well as quantitatively evaluate polymorph stability, for a previously not synthesized ZIF composition. Theoretical calculations were used to obtain an energy ranking and evaluate energy differences for a set of hypothetical, topologically-distinct structures of a fluorine-substituted ZIF. Calculations were then experimentally validated via mechanochemical screening and calorimetry which confirmed two out of three theoretically anticipated topologies, including a fluorinated analogue of the popular ZIF-8, while revealing an excellent match between the measured and theoretically calculated energetic difference between them. The results, which speak strongly in favor of ability of dispersion-corrected periodic DFT to predict the topological landscape of new ZIFs, also reveal the ability to use peripheral substituents on the organic linker to modify the framework thermodynamic stability.

Full Article

05 April 2019

This new publication, “Hypergolic zeolitic imidazolate frameworks (ZIFs) as next-generation solid fuels: Unlocking the latent energetic behavior of ZIFs” higlights novel electronic properties in these materials which were previously unknown.

Abstract: Hypergolic materials, capable of spontaneous ignition upon contact with an external oxidizer, are of critical importance as fuels and propellants in aerospace applications (e.g., rockets and spacecraft). Currently used hypergolic fuels are highly energetic, toxic, and carcinogenic hydrazine derivatives, inspiring the search for cleaner and safer hypergols. Here, we demonstrate the first strategy to design hypergolic behavior within a metal-organic framework (MOF) platform, by using simple “trigger” functionalities to unlock the latent and generally not recognized energetic properties of zeolitic imidazolate frameworks, a popular class of MOFs. The herein presented six hypergolic MOFs, based on zinc, cobalt, and cadmium, illustrate a uniquely modular platform to develop hypergols free of highly energetic or carcinogenic components, in which varying the metal and linker components enables the modulation of ignition and combustion properties, resulting in excellent hypergolic response evident by ultrashort ignition delays as low as 2 ms.

Full Article

First CASTEP Users Meeting in Birmingham is a Great Success!

20 March 2019

The first CASTEP Users Meeting was held this week in Birmingham, and organised by Andrew and Phil Hasnip. The meeting was a success, with speakers travelling from as far as Taiwan to attend the workshop. At the meeting, one of the Morris group PhD students, Angela Harper, took home the first place poster prize for her work on “Electronic Structure and Properties of Transition Metal Phosphides”. Featured in the image here is Bjoern Winkler from Goethe University, Frnakfurt, Germany, giving the first talk of the workshop on “Understanding phase transitions using CASTEP”. Andrew, and the rest of the CASTEP community are looking forward to hosting more workshops such as this one in the coming years, to make this an annual occurance. This is in addition to the CASTEP Workshop held each year in August for new users and CASTEP developers.

For more information on CASTEP, and to stay informed about upcoming workshops, visit the website

New Publication in Phys. Rev. B on Electronic Structure of Niobium Suboxides

26 February 2019

The crystal structures of transition metal oxides often feature octhedral motifs — one transition metal atom surrounded by six oxygens. Phases of niobium oxides take interesting crystal structures in which the octahedra connect via their corners to form larger block-like units, and those, in turn, stack up and next to each other to form the crystal. Through electronic structure calculations, we show that these block units affect the behaviour of electrons within the material in a peculiar way. Localised and delocalised electronic states coexist within the blocks, but are spatially separated. The delocalised states are present at the boundaries between the block superunits, while localised electrons are found in the interior. Using these principles, we can explain some interesting results from previous experimental work. Slightly reduced block-type niobium oxides are magnetic - and the magnetism arises from localised electrons in the block interior. Similarly, some reduced niobium oxides feature activated electron conductivity, while others are metallic - this is related to the fact that each block can only hold one localised electron. Overall, our work demonstrates elegantly the effect of the nanometre-sized superunits on the electronic behaviour of the materials.

Full Article

New Publication in Nature Communications on New Ways to Stick Atoms Together

08 January 2019

Atoms stick together to make the world around us through a set of different atom-atom interactions called bonds. Without atomic bonding, the universe would be just be one large gas with nothing solid in it at all.

The text-book four types of atomic bonding are ionic (think table salt), covalent (silicon chips), metallic (steels, iron etc) and van der Waals (how geckos stick to the ceiling). However, there is a fifth kind of bonding, called a non-covalent directional interaction. It is responsible for water’s unusual properties such as expanding on freezing (most liquids shrink) and having a high boiling point compared to other molecular liquids.

We care about this fifth kind of bonding as it can stick molecules together into molecular crystals which have a wide variety of uses, for example, capturing carbon dioxide from the atmosphere, detecting trace impurities and toxins, sensing biomolecules and a vast collection of pharmaceuticals. It’s similar to molecular Lego – the more different ways we can stick bricks together, the more useful (and fun!) materials we can make.

The halogen elements such as fluorine, chlorine, bromine, and iodine can form these fifth-kind bonds. Up until now they were thought to only bond to small, compact atoms like nitrogen or oxygen, limiting the ways molecular crystals could be assembled. In this international collaboration between UK, Canada and Croatia we show that we can make molecular crystals by bonding the halogen iodine to the much heavier phosphorus, arsenic and antimony atoms, some 2, 5 and 8 times more massive than oxygen respectively.

This research paves the way for many new molecular crystals with fantastic new properties. We show, for example, colossal expansion in a crystals with I…Sb bonds on heating.

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First CASTEP Users Workshop to be held in Birmingham 18th - 19th March

14 December 2018

The CASTEP Developers have announced that “The first annual CASTEP Users Workshop will take place 18th - 19th March 2019 at the University of Birmingham’s newly opened Edgbaston Park Hotel. The workshop is an opportunity to present research and discuss in an informal environment. There will be a lively informal atmosphere with plenty of opportunities for discussion and with this in mind all participants are encouraged to submit a poster title and abstract to promote our conversations. There will also be a prize for best PhD/PDRA poster.”

Details of the event can be found on the CASTEP website

Morris Group recognised as “Emerging Investigators in Solid-State Inorganic Chemistry” in ACS Virtual Issue

11 December 2018

In a December 2018 Virtual Issue of the ACS journal Inorganic Chemistry entitled “Emerging Investigators in Solid-State Inorganic Chemistry” the Morris group received recognition for their work on battery anode materials using ab initio random structure searching (AIRSS). The journal highlighted the Morris group’s work on Li/Sn and Li/Sb systems, which helped to identify the phases of these anode materials which form during battery cycling. Within the issue, young investigators and groups were mentioned who “…have started their independent laboratories in the past 5–8 years and published notable papers in the selected journals Inorganic Chemistry, Chemistry of Materials, and Journal of the American Chemical Society since 2016.” As the group continues to search for better battery materials, identify new phases of helical phosphorus, and develop new methods for density-functional theory, they continue to forge ahead in the field of solid-state inorganic chemistry.

See the full editorial here.

Read the Li/Sn Li/Sb paper here.

New Publication in Chemical Science

26 October 2018

We report the first examples of thiocyanate-based analogues of the cyanide Prussian blue com- pounds, MIII[Bi(SCN)6], M= Fe, Cr, Sc. These compounds adopt the primitive cubic pcu topology and show strict cation order. Optical absorption measurements show these compounds have band gaps within the visible and near IR region, suggesting that they may be useful for photocat- alytic applications. We also show that Cr[Bi(SCN)6] can reversibly uptake water into its framework structure pointing towards the possibility of using these frameworks for host/guest chemistry.

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New Publication in Physical Rev. B

16 October 2018

Indium oxide is a wide band gap semiconductor that provides the platform for most n-type transparent conductors. Optical absorption is dominated by a strong edge starting at the optical gap around 3.7 eV, but the material also exhibits a prominent absorption tail starting around 2.7 eV. We use first principles methods to show that this tail arises from interband transitions that are dipole forbidden at the static lattice level, but become dipole allowed via a dynamical symmetry breaking induced by nuclear motion. We also report the temperature dependence of the absorption onset, which exhibits a redshift with heating, driven by a combination of electron-phonon coupling and thermal expansion. We argue that the role of dynamical symmetry breaking in optical absorption is a general feature of semiconductors and that the computational design of novel materials for optical applications, ranging from transparent conductors to solar cells, should incorporate the lattice dynamics of the crystal.

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Andrew is mentioned in a news article on 1D materials at the University of Birmingham

02 October 2018

“Scientists are developing the smallest possible one-dimensional (1D) materials called ‘extreme nanowires’. Less than a nanometre in diameter, they are 10,000 times smaller than a human hair. Now, an EPSRC-funded collaboration between the Universities of Birmingham and Warwick has reached the ultimate limit – making wires that are just one atom in diameter.”

See the full article here

Congratulations to Jamie on his successful viva!

14 September 2018

He has completed the PhD in Physics from the University of Cambridge!

New Publication in J. Phys. Chem. A

30 August 2018

We describe the approach for modelling solid-state fluorescence spectra of organic crystalline materials, using the recent implementation of time-dependent density-functional theory (TD-DFT) within the plane-wave/pseudopotential code CASTEP. The method accuracy is evaluated on a series of organic cocrystals displaying a range of emission wavelengths. In all cases the calculated spectra are in good to excellent agreement with experiment. The ability to precisely model the emission spectra offers novel insight into the role of intermolecular interactions and crystal packing on solid-state luminescence of organic chromophores, allowing the possibility of in-silico design of organic luminescent materials.

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New Publication in Adv. Mater.

27 August 2018

A surge in interest of oxide‐based materials is testimony for their potential utility in a wide array of device applications and offers a fascinating landscape for tuning the functional properties through a variety of physical and chemical parameters. In particular, selective electronic/defect doping has been demonstrated to be vital in tailoring novel functionalities, not existing in the bulk host oxides. Here, an extraordinary interstitial doping effect is demonstrated centered around a light element, boron (B). The host matrix is a novel composite system, made from discrete bulk LaAlO3:LaBO3 compounds. The findings show a spontaneous ordering of the interstitial B cations within the host LaAlO3 lattices, and subsequent spin‐polarized charge injection into the neighboring cations. This leads to a series of remarkable cation‐dominated electrical switching and high‐temperature ferromagnetism. Hence, the induced interstitial doping serves to transform a nonmagnetic insulating bulk oxide into a ferromagnetic ionic–electronic conductor. This unique interstitial B doping effect upon its control is proposed to be as a general route for extracting/modifying multifunctional properties in bulk oxides utilized in energy and spin‐based applications.

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Angela wins a poster prize at the CASTEP workshop!

22 August 2018

Congratulations to Angela for winning the second place poster prize at the CASTEP workshop hosted at the University of Oxford.

New Publication in ACS Applied Materials & Interfaces

14 August 2018

The properties and applications of metal-organic frameworks (MOFs) are strongly dependent on the nature of the metals and linkers employed, along with the specific conditions employed during synthesis. Al-fumarate, trademarked as Basolite A520, is a porous MOF that incorporates aluminum centers along with fumarate linkers, and is a promising material for applications involving adsorption of gases such as CO2. In this work, the solvothermal synthesis and detailed characterization of the gallium and indium fumarate MOFs (Ga-fumarate, In-fumarate) are described. Using a combination of powder X-ray diffraction, Rietveld refinements, solid-state NMR spectroscopy, infrared spectroscopy, and thermogravimetric analysis, the topologies of Ga-fumarate and In-fumarate are revealed to be analogous to Al-fumarate. Ultra-wideline 69Ga, 71Ga and 115In NMR experiments at 21.1 T strongly support our refined structure. Adsorption isotherms show that the Al-, Ga-, and In-fumarate MOFs all exhibit an affinity for CO2, with Al-fumarate the superior adsorbent at 1 bar and 273 K. Static direct excitation and cross-polarized 13C NMR experiments permit investigation of CO2 adsorption locations, binding strengths, motional rates, and motional angles that are critical to increasing adsorption capacity and selectivity in these materials. Conducting the synthesis of the indium-based framework in methanol demonstrates a simple route to introduce porous hydrophobicity into a MIL-53-type framework, by incorporation of metal-bridging –OCH3 groups in the MOF pores.

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Congratulations to Angela for passing her MPhil viva!

12 August 2018

She will now continue in the Morris group as a PhD student.

Can wins a poster prize at Physics by the Lake!

04 August 2018

Can attended the 2018 Physics by the Lake summer school and won a poster prize for poster “First-Principles Study of Complex Oxides”

New Publication in J. Am. Chem. Soc.

01 June 2018

Na-ion batteries are promising alternatives to Li-ion systems for electrochemical energy storage because of the higher natural abundance and widespread distribution of Na compared to Li. High capacity anode materials, such as phosphorus, have been explored to realize Na-ion battery technologies that offer comparable performances to their Li-ion counterparts. While P anodes provide unparalleled capacities, the mechanism of sodiation and desodiation is not well-understood, limiting further optimization. Here, we use a combined experimental and theoretical approach to provide molecular-level insight into the (de)sodiation pathways in black P anodes for sodium-ion batteries. A determination of the P binding in these materials was achieved by comparing to structure models created via species swapping, ab initio random structure searching, and a genetic algorithm. During sodiation, analysis of 31P chemical shift anisotropies in NMR data reveals P helices and P at the end of chains as the primary structural components in amorphous NaxP phases. X-ray diffraction data in conjunction with variable field 23Na magic-angle spinning NMR support the formation of a new Na3P crystal structure (predicted using density-functional theory) on sodiation. During desodiation, P helices are re-formed in the amorphous intermediates, albeit with increased disorder, yet emphasizing the pervasive nature of this motif. The pristine material is not re-formed at the end of desodiation and may be linked to the irreversibility observed in the Na–P system.

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New Publication in ACS Nano

02 May 2018

Nanostructuring, e.g., reduction of dimensionality in materials, offers a viable route toward regulation of materials electronic and hence functional properties. Here, we present the extreme case of nanostructuring, exploiting the capillarity of single-walled carbon nanotubes (SWCNTs) for the synthesis of the smallest possible SnTe nanowires with cross sections as thin as a single atom column. We demonstrate that by choosing the appropriate diameter of a template SWCNT, we can manipulate the structure of the quasi-one-dimensional (1D) SnTe to design electronic behavior. From first principles, we predict the structural re-formations that SnTe undergoes in varying encapsulations and confront the prediction with TEM imagery. To further illustrate the control of physical properties by nanostructuring, we study the evolution of transport properties in a homologous series of models of synthesized and isolated SnTe nanowires varying only in morphology and atomic layer thickness. This extreme scaling is predicted to significantly enhance thermoelectric performance of SnTe, offering a prospect for further experimental studies and future applications.

Full Article

New PDRA Kamal Goswami joins the group at Birmingham

30 April 2018

He will be working on ab initio structure prediction and theoretical spectroscopy to study carbon nanotube (CNT) encapsulated 1D crystals.

PhD Studentship Available in the Group

28 February 2018

Deadline 30 April 2018. More details here

New Publication in the Journal of Chemical Science

06 January 2018

Computational evaluation of metal pentazolate frameworks: inorganic analogues of azolate metal–organic frameworks

From superconductors to carbon-based life, a wealth of structural and electronic complexity is obtainable from just 92 atomic building blocks. The way that atoms are bonded together is heavily prescribed by their size and the strength of the electronic bond.

Imagine the wealth of new material properties if we could design our own building blocks each with their own interaction strengths, size and electronic properties. Metal-organic frameworks (MOFs) are a way to realise this. Predicting how these molecular building blocks will join together is still hard, but using density-functional theory, the Morris group (UoB) in collaboration with the experimental Friščić group (McGill, Canada) have, surprisingly, predicted not just a new structure, but an entirely new topology of a metal-inorganic framework.

Stable pentazolate compounds have only very recently been synthesised, hence this paper demonstrates the wealth of new materials that are still to be discovered. Using the simplest of data-mining we predict a new topology, that is, a new way to arrange matter in 3D space, which we named, arhangelskite (after the first author Mihails). It is already inspiring further work using our more complex techniques in a race to discover what other surprises are out there. In the 21st century, what else is left to name?

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New Publication in ACS Crystal Growth and Design

03 January 2018

Experimental and Theoretical Investigation of Structures, Stoichiometric Diversity, and Bench Stability of Cocrystals with a Volatile Halogen Bond Donor

We present a combined experimental and theoretical study of the structures and bench stability of halogen-bonded cocrystals involving the volatile halogen bond donor octafluoro-1,4-diiodobutane, with phenazine and acridine as acceptors. Cocrystallization experiments using mechanochemistry and solution crystallization revealed three chemically and structurally distinct cocrystals. Whereas only one cocrystal form has been observed with acridine, cocrystallization with phenazine led to two stoichiometrically different cocrystals, in which phenazine employs either one or two nitrogen atoms per molecule as halogen bond acceptor sites. Cocrystal stability was evaluated experimentally by simultaneous thermogravimetric analysis and differential thermal analysis or differential scanning calorimetry, real-time powder X-ray diffraction monitoring of cocrystals upon storage in open air, and theoretically by using dispersion-corrected periodic density functional theory. The use of real-time powder X-ray diffraction enabled the comparison of rates of cocrystal decomposition, and the observed trends in cocrystal stability were reproduced by the ranking of theoretically calculated cocrystal decomposition enthalpies. Whereas all cocrystals eventually lose the volatile halogen bond donor upon storage in open air or by heating, these experimental and theoretical studies show that the cocrystal of acridine is the most stable, in agreement with its more basic properties. The stoichiometric variations of the phenazine cocrystal also exhibit a notable difference in stability, with the cocrystal containing the halogen bond acceptor and donor in a 1:1 stoichiometric ratio being of particularly low stability, decomposing in open air within minutes.

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New Publication in Physical Review Materials

07 December 2017

Germanium telluride has attracted great research interest, primarily because of its phase-change properties. We have developed a general scheme, based on the ab initio random structure searching (AIRSS) method, for predicting the structures of encapsulated nanowires, and using this we predict a number of thermodynamically stable structures of GeTe nanowires encapsulated inside carbon nanotubes of radii under 9Å. We construct the phase diagram of encapsulated GeTe, which provides quantitative predictions about the energetic favorability of different filling structures as a function of the nanotube radius, such as the formation of a quasi-one-dimensional rock-salt-like phase inside nanotubes of radii between 5.4 and 7.9Å. Simulated TEM images of our structures show excellent agreement between our results and experimental TEM imagery. We show that, for some nanotubes, the nanowires undergo temperature-induced phase transitions from one crystalline structure to another due to vibrational contributions to the free energy, which is a first step toward nano-phase-change memory devices.

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Andrew writes this week's Birmingham Brief -- Shedding Light on New Battery Materials: the vision of combining experiments with computation

02 December 2017

“Seeing” individual atoms is a tricky business. At such tiny length scales illumination by individual packets of light, called photons, will not work. Their wavelength, around 500 nanometres, (about 150th of a human hair) is simply too large to resolve atomic scale features in materials. To see how nature works at the atomic scale, transmission electron microscopy (TEM) uses a shorter wavelength particle, the electron. However, in the life-sciences this technique has proved unsuitable. Many biological molecules are too delicate: imaging them in an electron beam is like imaging a Ming vase with an artillery barrage.

Andrew, Bora and Matthew are awarded a 4 MCPUh computing grant

01 November 2017

The grant, “Ab Initio Structure Prediction For Next-generation Battery Materials”, provides resources on the new EPSRC Tier-2 supercomputer CSD3, hosted in Cambridge, which recently placed as the fastest academic supercomputer in the UK (#75 on the [ top500]).

Congratulations to Angela, winner of the 2017 LeRoy Apker Award from the APS!

01 October 2017

The citation states that the award is “for significant contributions to printed electronics research and outstanding leadership of the Society of Physics Students and Society of Women in STEM fields.” More information can be found on the APS website

Andrew is appointed to Senior Birmingham Fellow at the University of Birmingham.

01 October 2017

The Group’s centre of operations moves to Birmingham, UK.

Congratulations Martin!

01 July 2017

Martin becomes the first AJM group member to survive submit a PhD thesis, “'’Ab initio’’ anode materials discovery for Li- and Na-ion batteries”.

Investigating Sodium Storage Mechanisms in Tin Anodes: A Combined Pair Distribution Function Analysis, Density Functional Theory, and Solid-State NMR Approach

01 May 2017

The alloying mechanism of high-capacity tin anodes for sodium-ion batteries is investigated using a combined theoretical and experimental approach. Ab initio random structure searching (AIRSS) and high-throughput screening using a species-swap method provide insights into a range of possible sodium–tin structures. These structures are linked to experiments using both average and local structure probes in the form of operando pair distribution function analysis, X-ray diffraction, and 23Na solid-state nuclear magnetic resonance (ssNMR), along with ex situ 119Sn ssNMR. Through this approach, we propose structures for the previously unidentified crystalline and amorphous intermediates. The first electrochemical process of sodium insertion into tin results in the conversion of crystalline tin into a layered structure consisting of mixed Na/Sn occupancy sites intercalated between planar hexagonal layers of Sn atoms (approximate stoichiometry NaSn3). Following this, NaSn2, which is predicted to be thermodynamically stable by AIRSS, forms; this contains hexagonal layers closely related to NaSn3, but has no tin atoms between the layers. NaSn2 is broken down into an amorphous phase of approximate composition Na1.2Sn. Reverse Monte Carlo refinements of an ab initio molecular dynamics model of this phase show that the predominant tin connectivity is chains. Further reaction with sodium results in the formation of structures containing Sn–Sn dumbbells, which interconvert through a solid-solution mechanism. These structures are based upon Na5–xSn2, with increasing occupancy of one of its sodium sites commensurate with the amount of sodium added. ssNMR results indicate that the final product, Na15Sn4, can store additional sodium atoms as an off-stoichiometry compound (Na15+xSn4) in a manner similar to Li15Si4.

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Local Structure Evolution and Modes of Charge Storage in Secondary Li–FeS2 Cells

01 March 2017

n the pursuit of high-capacity electrochemical energy storage, a promising domain of research involves conversion reaction schemes, wherein electrode materials are fully transformed during charge and discharge. There are, however, numerous difficulties in realizing theoretical capacity and high rate capability in many conversion schemes. Here we employ operando studies to understand the conversion material FeS2, focusing on the local structure evolution of this relatively reversible material. X-ray absorption spectroscopy, pair distribution function analysis, and first-principles calculations of intermediate structures shed light on the mechanism of charge storage in the Li–FeS2 system, with some general principles emerging for charge storage in chalcogenide materials. Focusing on second and later charge/discharge cycles, we find small, disordered domains that locally resemble Fe and Li2S at the end of the first discharge. Upon charge, this is converted to a Li–Fe–S composition whose local structure reveals tetrahedrally coordinated Fe. With continued charge, this ternary composition displays insertion–extraction behavior at higher potentials and lower Li content. The finding of hybrid modes of charge storage, rather than simple conversion, points to the important role of intermediates that appear to store charge by mechanisms that more closely resemble intercalation.

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Congratulations to Part III student Can, who has been offered a Winton Scholarship starting October 2017.

01 March 2017

Can will continue his work in the group on developing crystal structure prediction methods and battery materials.

Encapsulated nanowires: Boosting electronic transport in carbon nanotubes

01 March 2017

The electrical conductivity of metallic carbon nanotubes (CNTs) quickly saturates with respect to bias voltage due to scattering from a large population of optical phonons. The decay of these dominant scatterers in pristine CNTs is too slow to offset an increased generation rate at high voltage bias. We demonstrate from first principles that encapsulation of one-dimensional atomic chains within a single-walled CNT can enhance the decay of “hot” phonons by providing additional channels for thermalization. Pacification of the phonon population growth reduces the electrical resistivity of metallic CNTs by 51% for an example system with encapsulated beryllium.

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Welcome to new post-docs Bora and Joseph and new student Polina!

01 February 2017

Joseph will be working on data mining of AIRSS results, Bora on solid-state electrolytes for next-generation batteries and Polina on structure prediction of 2D materials, joint with Prof Richard Needs.

Nathalie awarded Best Master's Thesis by the [ Swiss Society for Materials Science and Technology (SVMT)]!

01 October 2016

Many congratulations to Nathalie, who will be starting a PhD at the University of Bern next year.

Structural Evolution of Electrochemically Lithiated MoS2 Nanosheets and the Role of Carbon Additive in Li-Ion Batteries

01 September 2016

Understanding the structure and phase changes associated with conversion-type materials is key to optimizing their electrochemical performance in Li-ion batteries. For example, molybdenum disulfide (MoS2) offers a capacity up to 3-fold higher (∼1 Ah/g) than the currently used graphite anodes, but they suffer from limited Coulombic efficiency and capacity fading. The lack of insights into the structural dynamics induced by electrochemical conversion of MoS2 still hampers its implementation in high energy-density batteries. Here, by combining ab initio density-functional theory (DFT) simulation with electrochemical analysis, we found new sulfur-enriched intermediates that progressively insulate MoS2 electrodes and cause instability from the first discharge cycle. Because of this, the choice of conductive additives is critical for the battery performance. We investigate the mechanistic role of carbon additive by comparing equal loading of standard Super P carbon powder and carbon nanotubes (CNTs). The latter offer a nearly 2-fold increase in capacity and a 45% reduction in resistance along with Coulombic efficiency of over 90%. These insights into the phase changes during MoS2 conversion reactions and stabilization methods provide new solutions for implementing cost-effective metal sulfide electrodes, including Li–S systems in high energy-density batteries.

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New MPhil student Monica wins SIGHPC/Intel Computational and Data Science Fellowship

01 August 2016

Congratulations to Monica, who will be starting the MPhil in Scientific Computing in October. During her degree,

Vacancy: Postdoctoral Research Assistant/Associate in Computational Materials Modelling - (Fixed Term)

01 August 2016

The group is advertising a one-year (with the option to extend for a further 2 years) postdoctoral position. The project will be conducted in collaboration with Prof Clare Grey within the Department of Chemistry, University of Cambridge, Profs Bruce and Monroe at the University of Oxford and Dr Aguadero at Imperial College, London. Grey, Aguadero and Bruce will provide experimental expertise to support the findings of the in silico analysis. For more information please visit [ here] or contact Dr Andrew Morris.

Congratulations to Connie for passing her MPhil viva!

01 August 2016

She will now jet off to Stanford to start her PhD — best of luck Connie!

01 July 2016

The group has won funding for a joint experimental and computational project with collaborators in chemistry (Prof Clare Grey, PI) and researchers at Imperial College and the University of Oxford, as well as industrial partners.

An excerpt from the grant proposal discusses the objective: “Overall, the project aims to provide new strategies to improve the performance of SSLBs but will also result in new electrolyte designs that are suitable for to protect Li metal in other so-called “beyond Li-ion” batteries such as Li-air and Li-S and smaller batteries for internet communications technologies.”

The full proposal can be found here

Vacancy: Postdoctoral Research Assistant/Associate in Computational Materials Modelling - (Fixed Term)

01 July 2016

The group is advertising a one-year (in the first instance) postdoctoral position. This project focuses on developing new algorithms to determine structural similarity in crystalline materials, and for developing new in silico approaches to determining oxide ion conductivity in materials. For more information see [ here] or contact Dr Andrew Morris.

Jamie wins poster prize at CCP9

01 July 2016

Who won a prize for his poster entitled “First-principles structure prediction of encapsulated nanowires” at the CCP9 Young Researchers’ event in York, UK.

Rationalization of the Color Properties of Fluorescein in the Solid State: A Combined Computational and Experimental Study

01 June 2016

Fluorescein is known to exist in three tautomeric forms defined as quinoid, zwitterionic, and lactoid. In the solid state, the quinoid and zwitterionic forms give rise to red and yellow materials, respectively. The lactoid form has not been crystallized pure, although its cocrystal and solvate forms exhibit colors ranging from yellow to green. An explanation for the observed colors of the crystals is found using a combination of UV/Vis spectroscopy and plane‐wave DFT calculations. The role of cocrystal coformers in modifying crystal color is also established. Several new crystal structures are determined using a combination of X‐ray and electron diffraction, solid‐state NMR spectroscopy, and crystal structure prediction (CSP). The protocol presented herein may be used to predict color properties of materials prior to their synthesis.

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The Lennard-Jones Centre is pleased to announce a visit by Professor Nicola Spalding

01 May 2016

ETH, Zürich. Nicola is a highly distinguished theorist who has made many seminal contributions to new computational and theoretical tools for calculating the properties of complex solids and their application to the rational design and understanding of new multifunctional materials. She is a fellow of the APS, MRS and AAAS and has won numerous awards for her research and educational activities.

She has generously agreed to give a series of Masterclass lectures which will provide a unique opportunity for all LJC students and post-docs to learn about computational methods in complex solids and multiferroics. The lectures will be accessible to computational and theoretical physicists, chemists and materials scientists. All members of the LJC are welcome.

Martin invited to speak at the IOP group, BRSG: The Magnetic Resonance Group, 2nd August 2016

01 May 2016

PhD Student Martin Mayo invited to speak about his work on NMR predictions of lithium-ion batteries to the IoP BRSG: The Magnetic Resonance Group summer meeting.

Ab Initio Study of Phosphorus Anodes for Lithium- and Sodium-Ion Batteries

01 March 2016

Phosphorus has received recent attention in the context of high-capacity and high-rate anodes for lithium- and sodium-ion batteries. Here, we present a first-principles structure prediction study combined with NMR calculations, which gives us insights into its lithiation/sodiation process. We report a variety of new phases found by the ab initio random structure searching (AIRSS) and the atomic species swapping methods. Of particular interest, a stable Na5P4–C2/m structure and locally stable structures found less than 10 meV/f.u. from the convex hull such as Li4P3–P212121, NaP5–Pnma, and Na4P3–Cmcm. The mechanical stability of Na5P4–C2/m and Li4P3–P212121 has been studied by first-principles phonon calculations. We have calculated average voltages, which suggest that black phosphorus (BP) can be considered as a safe anode in lithium-ion batteries due to its high lithium insertion voltage, 1.5 V; moreover, BP exhibits a relatively low theoretical volume expansion compared with other intercalation anodes, 216% (ΔV/V). We identify that specific ranges in the calculated shielding can be associated with specific ionic arrangements, results that play an important role in the interpretation of NMR spectroscopy experiments. Since the lithium-phosphides are found to be insulating even at high lithium concentrations, we show that Li–P-doped phases with aluminum have electronic states at the Fermi level suggesting that using aluminum as a dopant can improve the electrochemical performance of P anodes.

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Nano-Phase Change Materials Website Launched

01 March 2016

The collaboration between this Group and the Warwick NPCM group has a new website. The global demand for smaller and more energy efficient devices has been sustained by a steady decrease in the scale on which silicon microelectronics can be manufactured. To continue this trend beyond the mid 2020s devices with dimensions of just 1-2nm will be required, likely using alternatives to silicon.

Group moves to the new £63M Maxwell Centre, in Cambridge.

01 December 2015

The centre will cover many aspects of fundamental physics, including advanced scientific computing, the theory of condensed matter, advanced materials and the physics of biology and medicine. This will build upon the research from the Winton Programme and “will not be conventional research or ‘business as usual’, but a major effort to go beyond the boundaries of traditional physical science concepts”

New graduate student Matthew Evans joins the group.

01 October 2015

He will be working towards a high-throughput treatment of disorder and database approaches to materials applications.

New MPhil Student Connie Hsueh joins the Group from Caltech.

01 October 2015

Connie will be working on novel anode materials for lithium ion batteries. Prior to coming to Cambridge, she completed my BS in Physics at the California Institute of Technology in the US. Her research experience up to this point has been diverse including biochemical diagnostics, defence technologies, and iron-cathode lithium-ion batteries.

Nathalie joins the group working on Mg ion batteries

01 October 2015

Nathalie will be working on magnesium ion batteries. She wrote her bachelor thesis about the “Influence of different intermetallic phases on the aging and degradation behaviour of Mg-Zn-Ca” under the supervision of Prof. Peter J. Uggowitzer. During her master’s she did a first research project with the title “Effect of epitaxial strain on cation and anion vacancy formation in MnO” under the supervision of Prof. Nicola A. Spaldin.

Thermodynamically Stable Lithium Silicide and Germanide compounds - New Paper

31 August 2015

Using software to predict the characteristics of materials before they’re synthesised in order to guide and interpret experiments, the researchers successfully predicted the structures of a series of lithium silicides, an important step in understanding batteries made of silicon, and have also predicted new structures for a battery based on germanium. Thermodynamically stable lithium silicides and germanides from density-functional theory calculations

New Postdoctoral Research Assistant Paulo V. C. Medeiros joins the Group

01 August 2015

Paulo will be working on nanotube encapsulated nanowires. He holds a PhD in Theoretical and Computational Physics from [ Linköping University], Sweden. He has experience in electronic structure calculations, materials modelling, computer simulations and scientific programing. Experience with using and modifying electronic structure codes. [

Andrew appointed Visiting Associate Fellow at University of Warwick, 2015-2018.

01 May 2015

This appointment coincides with [

Elucidation of the Local and Long-Range Structural Changes that Occur in Germanium Anodes in Lithium-Ion Batteries - New Paper

01 January 2015

Metallic germanium is a promising anode material in secondary lithium-ion batteries (LIBs) due to its high theoretical capacity (1623 mAh/g) and low operating voltage, coupled with the high lithium-ion diffusivity and electronic conductivity of lithiated Ge. In contrast to previous work, which postulated the formation of Li9Ge4 upon initial lithiation, we show that crystalline Ge first reacts to form a mixture of amorphous and crystalline Li7Ge3 (space group P3212). Which we predicted to be stable in our recent theoretical study

Ab Initio Structure Search and in Situ 7Li NMR Studies of Discharge Products in the Li-S Battery System - New Paper

01 November 2014

The high theoretical gravimetric capacity of the Li-S battery system makes it an attractive candidate for numerous energy storage applications. In practice, cell performance is plagued by low practical capacity and poor cycling. In an effort to explore the mechanism of the discharge with the goal of better understanding performance, we examine the Li-S phase diagram using computational techniques and complement this with an in situ 7 Li NMR study of the cell during discharge. Ab Initio Structure Search and in Situ 7Li NMR Studies of Discharge Products in the Li-S Battery System

New graduate student Jamie Wynn joins the group.

01 October 2014

He will be working on the structure prediction of encapsulated nanotubes and the entropy of point defects.

Well done to Martin Mayo!

01 September 2014

Who won a prize for his poster at the SMARTER4 conference in Durham, UK.

New graduate student Martin Mayo joins the group.

01 January 2014

He will be working on predicting the phases of materials that form within lithium ion batteries.