Enhancing Cycling Stability in Li-Rich Mn-Based Cathode Materials by Solid-Liquid-Gas Integrated Interface Engineering

Abstract

The specific capacity of Li-rich Mn-based cathode materials (LRM) can be enhanced by the oxidation of lattice oxygen at high voltages. Nevertheless, an irreversible oxygen loss emerges with cycling, triggering interlocking surface/interface issues and thereby the fast deterioration of cycling performance. Herein, a solid-liquid-gas integrated surface/interface modification method is presented to form a CEI preconstruction layer and defective heterostructure on the surface/interface of LRM material to improve its cycling stability greatly. The CEI preconstruction layer can effectively anchor on the surface/interface of LRM primary and secondary particles to induce a thin and exceptionally stable CEI layer during cycling, and then mitigate the TM dissolution and strengthen the stability of surface lattice oxygen. The introduced defective heterostructure can reduce the charge transfer resistance. As a result, the designed LRM cathode displays a high reversible capacity of 315 mAh g -1 at 0.1 C as well as high capacity retention of 83.3% at 1 C after 500 cycles. Outstanding voltage stability with a retention of 91.5% is achieved at 5 C after 500 cycles. This work opens an attractive path in manipulating the surface/interface stability of LRM to enhance its cycling performance for high-energy-density Li-ion batteries.

Keywords: Li-rich Mn-based cathode materials, CEI preconstruction layer, Defective heterostructure, Cycling stability