Next Generation Materials Chemistry

Rechargeable batteries have had a profound effect on modern day life, and will continue to do so as our demand for systems of energy storage continues to increase. The metal ion battery currently dominates the field, and finds applications on the small scale to power portable consumer electronics, through hybrid and electric vehicles, to the large scale for grid energy storage. Significant progress has been made in battery technology over the past two decades, including improvements in electrolyte and electrode materials. Currently, metal ion batteries such as Li ion systems are approaching their theoretical energy densities and specific capacities which are limited by the intercalation chemistry of the cathode material, with anode materials outperforming. As such, innovations in battery chemistry and cathode materials are required to continue this improvement; this involves both the discovery of new materials targeted for cathode application and the study of such materials to further the understanding of the intercalation mechanisms. This project will investigate new materials for metal ion cathodes (including Li+, Na+, Mg2+, or Al3+), and utilise novel methods to synthesise them.
Magnesium ion batteries in particular are currently of high interest in both the academic and industrial research sectors. Using the knowledge obtained from the recent advances in lithium ion technology and materials, magnesium ion batteries have the potential to provide alternative and complementary capabilities to existing technology. The use of magnesium ion batteries enhances safety over lithium counterparts, reduces cost as magnesium is much more earth-abundant, and the use of a divalent cation (Mg2+) increases the volumetric energy density over current monovalent (Li+) materials. The lower polarity of Mg2+ compared against Al3+ is beneficial to the Mg2+ ionic transport through the electrode material. Furthermore, it's possible to safely process metallic magnesium anodes under air (unlike metallic lithium anodes), and dendrite formation is negligible in Mg systems, fulfilling the important aspects for large-scale production; easy fabrication and safety operation in devices. Currently, the development of magnesium ion batteries is impeded by the limited choice of available cathode materials that offer both high capacity and reversibility.
This project focusses specifically at the forefront of materials research for magnesium ion cathode materials, in order to drive the production of next-generation metal ion batteries. The synthesis and discovery of new Mg-based materials will be explored, including oxide and non-oxide compounds that can lead to interesting and unique structural chemistry. The structures and electrochemical properties of these materials will be assessed using in-house battery cell preparation and cycling methods. Complete characterisation of the materials will be carried out using a range of techniques including operando measurements at Diamond Light Source (X-ray absorption spectroscopy, X-ray powder diffraction) and ISIS (neutron powder diffraction) to elucidate the structural evolution upon cycling and understand the mechanisms of ionic transport on an atomistic scale in these new materials. Further characterisation on material performance will be performed by the external partner (Johnson Matthey - below) with the aim of accelerating the progression of new materials from the academic laboratory into industry and manufacture.
Johnson Matthey are involved in this project as external co-funders; James Cookson in particular is the external supervisor (james.cookson@matthey.com). Johnson Matthey's address is Technology Centre, Blounts Court, Sonning Common, Reading, RG4 9NH.