Excellent rate capability and cycling stability in Li⁺-conductive Li₂SnO₃-coated LiNi_0.5Mn_1.5O₄ cathode materials for lithium-ion batteries

High-voltage LiNi_0.5Mn_1.5O₄ is a promising cathode candidate for lithium-ion batteries (LIBs) due to its considerable energy density and power density, but the material generally undergoes serious capacity fading caused by side reactions between the active material and organic electrolyte. In this work, Li⁺-conductive Li₂SnO₃ was coated on the surface of LiNi_0.5Mn_1.5O₄ to protect the cathode against the attack of HF, mitigate the dissolution of Mn ions during cycling and improve the Li⁺ diffusion coefficient of the materials. Remarkable improvement in cycling stability and rate performance has been achieved in Li₂SnO₃-coated LiNi_0.5Mn_1.5O₄. The 1.0 wt% Li₂SnO₃-coated LiNi_0.5Mn_1.5O₄ cathode exhibits excellent cycling stability with a capacity retention of 88.2% after 150 cycles at 0.1 C and rate capability at high discharge rates of 5 C and 10 C, presenting discharge capacities of 119.5 and 112.2 mAh g^-1, respectively. In particular, a significant improvement in cycling stability at 55 °C is obtained after the coating of 1.0 wt% Li₂SnO₃, giving a capacity retention of 86.8% after 150 cycles at 1 C and 55 °C. The present study provides a significant insight into the effective protection of Li-conductive coating materials for a high-voltage LiNi_0.5Mn_1.5O₄ cathode material.