Neutron pair distribution function analysis of oxygen redox model system Li2MoO4

Utilisation of reversible oxygen redox activity in lithium-ion cathode materials is the current forefront approach for obtaining high energy density lithium-ion batteries. However, there is considerable debate about the mechanisms of anion redox, and how the structure of a material determines it’s anion redox activities. Here, we propose to study a model anion redox system, Li2MoO4 which contains molybdenum in a Mo(VI) (d0) state suggesting that the significant capacity (80 – 100 mAh/g) originates from pure anion redox. The structure can be altered from phenacite to spinel mechanochemically, offering the opportunity to probe the role of local atomic structure of anion redox activity. We propose to use neutron pair distribution function analysis to study this material as a function of charge, due to the limited crystallinity of the spinel sample and the disordered charge products.