Mitigating the effects of Climate Change depends critically on pervasive sustainable energy. Energy from renewables is sporadic and electricity demand and generation peaks do not match throughout the day. Air pollution in cities can only be solved by “green” transport. For both grid level storage and automotive there is urgent need for new battery materials with superior performance. Next-generation batteries (NGB) materials require a disruptive change. These new materials must be concurrently safe, cheap, and comprise only abundant constituents in line with UoB’s Global Challenges Research themes and aligned with both the Birmingham Energy Institute and the Birmingham Centre for Strategic Elements & Critical Materials.
To diversify from lithium’s restrictive geographical availability, sodium-ion batteries have been proposed. Na+ has tantamount to limitless supply from seawater. However, due to the larger ionic radius of Na+, the performance of intercalation anodes for these systems is very poor compared to graphite used as standard LIB anodes. Alternatives to intercalation, alloying or conversion anodes are more complex, requiring knowledge of the full phase diagram of a candidate system, however they promise order of magnitude improvements in capacity  and can be designed from sustainable, abundant materials. Conversion mechanisms by their nature are accompanied by large structural transformations which accelerate battery degradation.
Conventional experimental-based approaches to materials discovery, which can rely heavily on trial and error, are time-intensive and costly. To cover the vast design space and accelerate these new NGB materials from TRL1, the only possible recourse is rational computational design. Carrying out experiments concurrently allows for new avenues to be explored with constant feedback between each other; this bootstrapping process accelerates the discovery of novel NGB materials.
In the spirit of using only cheap and abundant elements we propose the sodium-ion silicon sulphide conversion anode (the triple-S).
We will use the ab initio random structure searching (AIRSS) method to conduct a systematic investigation of Si-S and Ge-S binary compounds in order to search for novel materials for lithium-ion battery (LIB) anodes. AIRSS is a high-throughput, density functional theory-based approach to structure prediction which has been successful at predicting the structures of LIBs containing sulfur  and silicon and germanium .
i. Data-Driven Discovery: We have shown that by alloying a small quantity of a third element, the electrical conductivity of an anode can be drastically increased . We propose that by introducing another element that can alloy with the active ion, synergistic reactions can occur that ameliorate volume expansions and can exhibit rapid topotactic phase transitions. Our initial targets build on our previous work on silicides, e.g. SiS2, GeS2.
ii. High-Throughput Characterisation: Once each phase diagram has been constructed, model compounds and electrochemically synthesised compounds will be produced and structurally characterised. Where phases have limited long range order, the pair distribution function analysis method, in which PKA is an expert, will be used to compare experimental phases with calculated phases using our in-house database screening software (MATADOR).
In order to reach out to other experimental groups within Birmingham (Dr D. Reed, M&M and Dr. M. Britton, Chem.) we will also predict Raman and NMR spectra. These allow the easy interpretation of experimental synthesis.
The student will receive training in not only computational but also experimental materials science methods. As such, they will gain a wide range of skills and experience which will make them attractive for future employment in both industry and academia.
The project is anticipated to be a mixture of code development, high-throughput computation (~80%) and experimental characterisation (~20%).
The candidate will have a 1st class Undergraduate or Masters degree (or equivalent) in Physics, Chemistry, Materials Science or related discipline. A strong background with programming (e.g. python, Fortran0?, C, C++), computational quantum mechanics, solid-state materials or electrochemistry would be advantageous.
Applications should be made through the university’s online application system. Please contact Dr Andrew Morris in advance of applying providing a CV and cover letter summarising your research interests and previous experience, and the contact details of two people able to provide a letter of reference. Further information can be obtained by emailing Dr Andrew Morris ([email protected]
) or Dr Phoebe Allan ([email protected]