Conversion of residual lithium into fast lithium ion conductor coating to achieve high cycle life LiNi_0.8Co_0.15Al_0.05O₂ cathode for lithium ion battery

Nickel-rich layered LiNi_0.8Co_0.15Al_0.05O₂ (NCA) is considered one of the most promising cathode materials owing to its high energy density and excellent cycling performance. However, the detrimental phase transitions and the interfacial side reactions during cycling have hindered its further development. Here, NCA with different content Li₃VO₄ coatings (LVO) are synthesized by high temperature solid phase method. The physical and electrochemical performance tests indicate LVO as a fast lithium ion conductor layer effectively improves the Li⁺ diffusion rate. More importantly, the preparation of fast lithium ion conductor LVO layer consumes residual lithium and prevents the direct contact between the active material and the electrolyte, thus enhancing the stability of electrode material. As a results, the 2.0wt% LVO-NCA shows best electrochemical performance. Even after 300 cycles at 1 C, its capacity retention rate reaches 83.1% compared to 55.3% for pristine NCA. This strategy provides a new idea for the development of high nickel ternary cathode materials.