XES studies on simultaneous cationic and anionic redox (SCAR) active VS4 cathodes for Mg batteries

This project aims to study the redox chemistry in simultaneous cationic and anionic redox (SCAR) Sulphur-based VS4 cathodes in Mg batteries. Those cathode materials work extraordinarily well with monovalent ions and also show promising results in the multivalent case as demonstrated in our previous studies using a new a solid-state synthesis. Yet, their redox mechanisms are not fully understood, especially in extended cycles with capacity dropping. We apply to use synchrotron tender XES to investigate the redox behaviors of both transition metal cations and the S anions in response to Mg insertion and extraction, and compare their contributions to the change of capacity. The findings will help understand fundamental mechanisms beyond intercalation within the SCAR-based cathode materials, and aid the discovery of novel compositions with enhanced properties, enabling faster diffusion and extending the portfolio of Mg cathode materials.