Doping strategies for enhancing the performance of lithium nickel manganese cobalt oxide cathode materials in lithium-ion batteries

Lithium-ion batteries (LIBs) are pivotal in the electric vehicle (EV) era, and LiNi1-x-yCoxMnyO2 (NCM) is the most dominant type of LIB cathode materials for EVs. The Ni content in NCM is maximized to increase the driving range of EVs, and the resulting instability of Ni-rich NCM is often attempted to overcome by the doping strategy of foreign elements to NCM. No less than 46 elements have been considered as a doping element in NCM, and their effects on the LIB performance have been investigated in about 400 research articles. Elements such as Al, Zr, Na, and F are the most popular doping choices, and some elements show a lack of consensus on the effectiveness of doping approach. Therefore, we systematically analyze the effects of each doping element by breaking down the LIB performance into capacity, rate capability, and cycleability. Further, we construct a periodic table presentation for the doping approach in order to make readers grasp this research area at a glance. The unbiased evaluation of the doping effectiveness for an element based on the statistical analysis of relevant references would be an enormous help to LIB industry and academia.