Fast lithium-ion conductor LiTi₂(PO₄)₃ coating modified LiNi_0.8Co_0.15Al_0.05O₂ as cathode material for lithium-ion batteries

Layered high nickel LiNi_0.8Co_0.15Al_0.05O₂ (NCA), as one of the most promising cathode materials in lithium-ion batteries, has high specific capacity, stable structure, and environmentally friendly characteristics. However, severe Li⁺/Ni²⁺ mixing and surface side reactions hinder its further development. To solve these issues, fast lithium-ion conductor LiTi₂(PO₄)₃ was coated on the surface of NCA using wet chemistry and high-temperature solid-state methods. The LiTi₂(PO₄)₃ coating not only reduces the Li⁺/Ni²⁺ mixing effect of NCA, but also effectively suppresses the side reactions between the electrolyte and NCA surface, thereby improving its cycling performance. After 200 cycles at 1C, the capacity retention rate of pure NCA is 72.1%, while the corresponding value of 2.0wt% LTP-NCA is 88.0%. Even at a high rate of 5C, due to high Li⁺ diffusion rate of LiTi₂(PO₄)₃, the capacity of 2.0wt% LTP-NCA reaches 152.8 mAh g⁻¹ compared to 136.2 mAh g⁻¹ of pure NCA. Therefore, fast lithium-ion conductor coating modification effectively improves electrochemical performance, which is beneficial for the further commercialization of NCA cathode materials.