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

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-LiCoO2 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/LiCoO2 contact interface suppresses lattice O-2 release of LiCoO2, thus significantly improving the structural and thermal stability at high delithiation states. Meanwhile, by contacting with high-electron-conductivity LiCoO2, the redox activity of olivine is further activated. Therefore, a stable operation of both olivine-LiCoO2 and olivine-LiNi0.8Co0.1Mn0.1O2 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.