Improved Stability of Single‐Crystal LiCoO<sub>2</sub> Cathodes at 4.8 V through Solvation Structure Regulation
Zhenjie Zhang, Jing Wang, Xinyi Sun, Chuanchao Sheng, Maozeng Cheng, Hang Liu, Yiting Wang, Haoshen Zhou, Ping He
Abstract
Abstract Increasing the charging cut‐off voltage can significantly improve the capacity of LiCoO 2 cathode. However, when the cut‐off voltage exceeds 4.5 V (vs Li/Li + ), LiCoO 2 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 LiCoO 2 to enhance the structural stability of LiCoO 2 . Moreover, a 3 Å 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||LiCoO 2 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 LiCoO 2 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 LiCoO 2 battery system, providing a professional approach to addressing the challenges of high‐voltage LiCoO 2 .