A simple and efficient strategy to construct Li-rich layered materials with surface layered/spinel heterostructures

In Li-rich layered oxides cathode materials (LR materials), spinel structure was widely introduced to suppress the structure attenuation and voltage decline during cycling. In this study, LR materials with surface layered/spinel heterostructures have been fabricated by a simple high-temperature post-treatment method. The existence of the surface spinel structure in synthesized materials was verified via X-ray diffraction, Raman spectra, and transmission electron microscopy. Moreover, the synthesized materials demonstrated remarkable electrochemical performance, especially their cycling performance. After optimization, the LR-850 samples showed the best electrochemical performances, that is, the capacity retentions are 126.97% at 1 C after 200 cycles and 92.2% at 5 C after 700 cycles, and the discharge-specific capacities are 139.6 mAh·g−1 at 5 C and 111 mAh·g−1 at 10 C, respectively. These electrochemical properties improvements are attributed to the introduction of the surface spinel structure in LR materials which could enhance the structural stability and provide 3D lithium ion diffusion paths.