Understanding the microstructural origin of high voltage instability in high-Ni NMC cathodes

To meet the rapid goals of electrification of the transport sector, it is imperative to build batteries that have a higher capacity, and are resilient and safe. One of the popular ways of achieving this is by using high Ni NMC (LiNixMnyCo1-x-yO2) cathodes, at higher voltages. This is achieved by substituting Ni for Co in the NMC material. However, this higher capacity per cycle comes at the cost of cycling stability. Particularly when accessing high voltages, these materials are prone to cracking. Therefore, in order to improve the stability of low-Co/high-Ni NMCs, we aim to systematically study the underlying mechanism for this high voltage morphological instability. Specifically, we aim to conduct experiments of polycrystal and single crystal NMCs with varying Ni content, to better understand the role of inter-granular anisotropy in causing high voltage instabilities in high Ni NMCs.