Recent progress in coating modification of lithium-manganese-rich cathode materials for lithium-ion batteries

As a new generation of lithium battery cathode material，lithium-rich manganese-based cathode material (LMCM) has the advantages of low cost and high capacity．However, problems such as irreversible structural transformation and interfacial reactions of lithium-rich manganese-based materials, leading to defects such as surface cracks, transition metal dissolution and layered structure collapse during the cycling process, which restrict the commercial application of this material. Surface coating has been proved to be an effective method to suppress the side reactions between electrode and electrolyte, and further improving rate capability and cycling stability of Li-rich manganese-based materials. There are many reports on the modification of surface coating, however, the review paper on this field is rarely observed, thus, in this paper，the characteristics and functions of the coatings used in lithium-rich manganese-based cathode materials are reviewed，and the mechanism of coating modification is deeply analyzed from the perspective of material structure and failure mechanism. From the point of view of coating modification mechanism, this paper systematically summarizes the previous researches on monolayer coating, double layer/gradient coating and in-situ coating. Therefore, the latest progress in the research of modification of Li-rich Mn-based cathode materials was summaried in this paper from aspects of modification substances, the characteristics and functions of in situ modification, and further analyzes the action mechanism of modification in improving cycle performance of Li-rich Mn-based from the perspectives of material structure and failure mechanism, and provides an outlook on the future development direction of LMCM.