Study on annealing treatment of spinel <scp> LiNi ₀ </scp> _. <scp> ₅ Mn ₁ </scp> _. <scp> ₅ O ₄ </scp> as cathode materials for <scp>high‐voltage</scp> lithium‐ion batteries

The cathode material LiNi0.5Mn1.5O4 has drawn considerable attention for the high-voltage discharge platform, high power density, and environmental friendliness. However, Mn3+ inside the material leads to the generation of Ni-O impurities, which contributes to a 4.1 V voltage platform in the charge-discharge process. To overcome this phenomenon, spinel LiNi0.5Mn1.5O4 was prepared by a high-temperature solid-phase method in this article, and samples were annealed after that. Impacts of annealing treatment on properties of LiNi0.5Mn1.5O4 were studied and an effective annealing treatment method was proposed. The charge and discharge test shows that the sample treated by annealing at 600°C for 8 h has the highest capacity (121 mAh/g) and the best cycle capacity retention rate (93.4%). XPS tests showed that the treatment…