Improved Stability of Single-Crystal LiCoO2 Cathodes at 4.8 V through Solvation Structure Regulation

Increasing the charging cut-off voltage can significantly improve the capacity of LiCoO2 cathode. However, when the cut-off voltage exceeds 4.5 V (vs Li/Li+), LiCoO2 undergoes irreversible phase transitions, leading to particle cracking and structural failure. Additionally, the decomposition of the electrolyte compromises the stability of the cathode/electrolyte interface, resulting in diminished battery capacity. Herein, the elements Al, Mg, and Zr are doped into single-crystal LiCoO2 to enhance the structural stability of LiCoO2. Moreover, a 3 & Aring; zeolite film is used to regulate the solvation structure to enhance the oxidation resistance of the electrolyte. This design enables a more stable cathode/electrolyte interface during high-voltage cycling. At a cut-off voltage of 4.8 V, the Li||LiCoO2 battery exhibits an initial discharge capacity of 236.2 mAh g(-1) at 0.1 C and maintains 86.6% capacity retention after 100 cycles at 1 C. The pouch full cell, which utilizes a graphite anode and LiCoO2 cathode, operating within a charge-discharge range of 2.8-4.65 V, achieves a specific energy of 276 Wh kg(-1) with 81% capacity retention after 200 cycles. This work introduces a desolvated electrolyte into the LiCoO2 battery system, providing a professional approach to addressing the challenges of high-voltage LiCoO2.