Mechanistic investigations into the electrochemical performance of partially disordered LiNiO2

Cation-disordered oxides are attracting a great deal of attention as the next generation high energy Li-ion cathode materials given their exceptionally high capacities (~ 300 mAh g-1), and their high chemical versatility. Moreover, unlike common layered oxide cathodes, like LiNiO2 (LNO), the disordered arrangement of cations in the network enables isotropic, small volume changes for enhanced stability and electrochemical properties. Since its discovery in 1954, LNO has been thoroughly investigated as cathode for Li-ion batteries given its high operating voltage and electrochemical capacity. However, its commercial use has been hindered by its thermal instability at high degrees of de-lithiation as well as by its fast capacity fade upon consecutive cycles. We have recently developed a method to convert the layered (LNO) into a cation-disordered rock salt (DRS-LNO) via gradual introduction of disorder resulting in an improvement in its electrochemical performance. With this proposal we intend to unveil the structure of new partially disordered LNO (PD-LNO) cathode materials showing different capacity and stability depending on the degree of disorder in the system. Big-box modelling of this data will provide definitive information on the local atomic rearrangements and its effect on the O-redox and electronic structure of the material, to provide a fundamental understanding on the mechanism behind the differences in capacity and stability observed in these materials.