Gradient doping Mg and Al to stabilize Ni-rich cathode materials for rechargeable lithium-ion batteries

Nickel-rich layered oxides are attracting extensive interest as cathode materials to build high-energy lithium-ion batteries, but their intrinsic structural instability and interfacial parasitic reactions deteriorate the cycling performance. Herein, we report concentration-gradient Mg and Al doped LiNi0.95Co0.03Al0.01Mg0.01O2 (NCAMg) as a stable and high-capacity cathode material. The obtained NCAMg microparticles exhibit outstanding cyclability (capacity retention of 95.6% after 100 cycles) and remarkable rate capability (172.9 mAh g(-1) at 10 C). The gradient Mg and Al doping boosts the electrochemical performance by restraining the undesirable H2-H3 phase conversion and the anisotropic volume change. Moreover, the enrichment of Mg and Al at particle shell enhances the Li-ion diffusivity, inhibits the growth of microcracks, and significantly improves the thermal stability over LiNiO2. The results indicate that Mg and Al gradient co-doping is an efficient and practical route to upgrade Nirich layered oxide cathode materials for LIBs.

Automated summary

This study reports a concentration-gradient Mg and Al doped cathode material, which exhibits stability, high capacity, outstanding cyclability, and remarkable rate capability. The gradient co-doping boosts the electrochemical performance and enhances Li-ion diffusion and thermal stability.