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Li-rich Mn-based materials, which is composed of a layered rhombohedral LiTMO2 (TM= Ni, Co, Mn) component and a monoclinic Li2MnO3 component, showing a high specific capacity (> 250 mAh g-1). In contrast to the conventional LiTMO2 materials, the higher capacity stems from the extra activation of the Li2MnO3 component with partially reversible oxygen redox above 4.5 V, whereas it also brings some fatal drawbacks. Voltage decay and hysteresis result in the continuous capacity loss and restrict its large-scale commercial applications. At present, the in-depth mechanism of performance decay and its relationship with structural evolution are still poorly understood [1].

Ideally, Li+ ions are reversibly migrated into and out of the framework of layered materials under the driving of voltage. However, in actual, uneven Li+(de) intercalation and heterogeneous electrochemical reactions are often occurred in these …