Recent progress in Li and Mn rich layered oxide cathodes for Li-ion batteries

Li and Mn rich (LMR) layered oxides, written as xLi2MnO3·(1 − x)LiMO2 (M = Mn, Ni, Co, Fe, etc.), have been widely reported in recent years due to their high capacity and high energy density. The stable structure and superior performance of LMR oxides make them one of the most promising candidates for the next-generation cathode materials. However, the commercialization of these materials is hindered by several drawbacks, such as low initial Coulombic efficiency, the degradation of voltage and capacity during cycling, and poor rate performance. This review summarizes research progress in solving these concerns of LMR cathodes over the past decade by following three classes of strategies: morphology design, bulk design, and surface modification. We elaborate on the processing procedures, electrochemical performance, mechanisms, and limitations of each approach, and finally put forward the concerns left and the possible solutions for the commercialization of LMR cathodes.