Nickel-rich layered oxide cathodes are getting significant attention because of the attractive initial cycle electrochemical performance, lower cost, and reduced toxicity of lithium ion batteries (LIB). There are factors hindering the stable performance of Ni rich cathodes which include cation mixing after synthesis and/or during electrochemical cycling, oxygen activity at high voltage (≥ 4.3 V), reduced thermal stability and structural distortion during cycling. Stoichiometric LiNiO2 is difficult to synthesize and transforms to multiple crystallographic phases on cycling. The layered oxides of nickel, manganese and cobalt (NMC) are found to be structurally compatible to provide elastic network for lithium deintercalation/intercalation, however the exact role of Mn and Co in NMC cathodes is still not clear. Generally, the change in oxidation state of Ni determines the reversible electrochemical capacity, Co and Mn ions are believed to provide structural stability. Therefore, Ni rich composition with suitable Mn and/or Co doping would be a preferred choice. A series of Ni rich layered oxide cathodes with similar morphology and physical properties have been synthesized to study the effects of Mn and Co doping on the structure and electrochemical performance.

The oxidation state and local environment (bond length, coordination number, thermal disorder) of transition metal ions get changed during charge/discharge cycling. In-situ and ex-situ X-ray absorption spectroscopy (XAS) in which individual elements (Ni, Mn, Co) are probed to scrutinize the electronic state and local geometry. Determining these properties will give insight into the degradation/aging mechanism of Ni rich cathodes.