Blending Layered Cathode with Olivine: An Economic Strategy for Enhancing the Structural and Thermal Stability of 4.65 V LiCoO₂

Abstract

Abstract The intrinsic poor structural and thermal stability of high‐voltage layered cathodes are aggravated as the charging depth increases, which severely threatens the cycle life and safety of the battery. Herein, without modifying the high‐voltage layered cathode itself, a simple and economic blending strategy is introduced, and an olivine‐LiCoO 2 blended cathode featuring superior comprehensive performance (energy, power, cycle‐life, and safety) at 4.65 V is fabricated. The strong bonding affinity at the olivine/LiCoO 2 contact interface suppresses lattice O 2 release of LiCoO 2 , thus significantly improving the structural and thermal stability at high delithiation states. Meanwhile, by contacting with high‐electron‐conductivity LiCoO 2 , the redox activity of olivine is further activated. Therefore, a stable operation of both olivine‐LiCoO 2 and olivine‐LiNi 0.8 Co 0.1 Mn 0.1 O 2 blended cathode is achieved under harsh cycling conditions (high voltage or elevated temperature) and long‐life pouch‐cell (91.6% capacity retention after 1000 cycles) is harvested, demonstrating the feasibility and universality of this economic blending strategy on heterogenous cathode candidates.