Due to high specific capacity and cost performance, high-nickel cathode materials have received much attention. However, its further application is hindered by poor stability and safety performance during cycling. In this work, Ni-rich LiNi0.8Mn0.2O2 materials were prepared through microwave-assisted co-precipitation followed by high-temperature solid-phase method, which can be further modified by doping different proportions of Co and Al.The as-prepared materials are characterized and tested with different methods. As a result, LiNi0.8Mn0.1Co0.08Al0.02O2 (NMCA-2) exhibits the best electrochemical performance, whose capacity retention rate reaches 91.39% after 100 cycles at 1C in the voltage range between 2.75 and 4.35 V, and still owns a specific discharge capacity of 160.03 mAh•g -1 at 5C. Its excellent cyclic retention rate can be attributed to the restrained irreversibility of H2→H3 phase transition during cycling with Co and Al doping, and the lower reaction polarization which contributed to the decline of charge transfer resistance, resulting in good cycle and rate performance of the material. Furthermore, high thermal stability of NMCA-2 improves the safety of the material.

Layered oxides with high nickel content are advanced cathode materials for high-energy-density lithium-ion batteries but still suffer from severe voltage decay and cycling instability. Herein, a nano-Li 2 SnO 3 coating and Sn 4+ -doping co-stabilized Co-free LiNi 0.8 Mn 0.2 O 2 (NM-82) cathodes were synthesized through the adsorption of tin dioxide sol, followed by hightemperature calcination. Profiting from co-benefits, the electrochemical reversibility and rate capability of the NM-82 electrode have been significantly improved. Herein, the NM-82 electrode modified with 2 wt % Li 2 SnO 3 (NM@ Sn-2) achieves the largest specific capacity with remarkable capacity retention. The enhanced cycle stability is also revealed in the graphite/NM@Sn-2 soft pack battery, which features a reversible capacity of 173.20 mA h g −1 and a high capacity retention of 90.54%, outperforming those of the NM-82 cathode (154.09 mA h g −1 and 81.23%) at 0.2 C after 300 cycles. The improved performance of the NM@Sn-2 cathode originates from its stronger structure, lower Li/Ni cation mixing degree, and faster Li + kinetics, also verified by theoretical calculations. Therefore, the one-step construction of nano-Li 2 SnO 3 coating coupling with Sn 4+ doping strategy shows a promising strategy to mitigate the capacity deterioration of the Co-free Ni-rich layered oxides.