In-situ generate spinel phase on a glucose-derived carbon-coated lithium-rich layered oxide cathode materials and its improved electrochemical performance

Abstract

Lithium-rich layered oxide cathode material gains a great concern as a potential cathode material for high energy density lithium-ion batteries recently; however, the low coulombic efficiency and poor rate performance still impede its commercial applications. In this work, a Li-rich@spinel@carbon heterostructure cathode material was synthesized via a solvothermal method together with in situ synchronous carbonization-reduction method. The unique structure fabricates fast Li+ diffusion channels of in situ-generated spinel structure (Fd-3 m) and electrons highway of carbon coating on the surface of lithium-rich cathode materials. Corresponding to the high lithium-ion diffusion coefficient and electric conductive, the heterostructures’ cathode material delivers a high discharge capacity of 313.9 mAh g−1 at 0.2 C and superior rate performance of 186.1 mAh g−1 at 5 C. The dual protective layer of spinel phase and carbon also help to improve the capacity retention of the samples (which remains 227.3 mAh g−1 and a retention of 102.7% after 100 cycles at 1 C rate). This work opens up a new route in terms of the design and synthesis of multi-phase cathode electrode materials for high performance energy storage devices.