A short review on fast charging of Ni-rich layered oxide cathodes

Fast charging (similar to 6 C rate) of Li-ion batteries (LIBs) is a key requirement to practically realize the growth of the electric vehicles (EVs) market. According to the US Department of Energy (DOE), the fast charge goal is an average of 20 mi min-1 (miles added per minute) or more. However, current state-of-art battery technologies are still far away from the requirements. Ni-rich layered oxide materials are promising cathode materials for the long run due to their high practically achievable capacity of 200 mAh g(-1) at an average voltage of 3.8 V vs. Li+ /Li. Under fast charging, Ni-rich cathodes undergo anisotropic volume change followed by microcracks formation. As the Ni content increases, the particle crack formation becomes more severe under fast charging. This review article presents a mechanistic insight into the degradation of Ni-rich cathode materials during fast charging, bulk and surface structural evolution during delithiation-lithiation, lithium-ion diffusion kinetics, an overview of the mitigation strategy, and the practical reality of Ni-rich layered oxide cathode materials for fast charging applications.