Nano-Particulate Surface Pinning of CeO2 Enables Durable High-Voltage Lithium-Ion Batteries.

Elevating the cut-off voltage of LiCoO2 (LCO) cathode in lithium-ion batteries (LIBs) enhances capacity but increases structural instability. While surface coatings are used to mitigate structural degradation at high voltages, conventional full coverage coatings often fail to withstand the cyclic mechanical stress, resulting in crack formation and performance decay. Here, a multifunctional CeO2 nanoparticle (NP) pinning structure is designed as a surface coating on LCO (LCO@CeO2) to enable stable operation at a high cut-off voltage of 4.6 V (vs Li/Li+). This surface pinning architecture balances structural integrity with minimal inactive material usage. The CeO2 NPs are strategically anchored to the LCO surface, creating a pinning structure that accommodates volume changes and suppresses fracture formation in the cathode. Moreover, the CeO2-mediated fast Li+ transport pathways are established, improving high-rate capability. The interspersed CeO2 NPs also act as oxygen reservoirs, stabilizing reversible (O2)3- species during high-voltage oxygen anionic redox reactions. Consequently, the optimized LCO@CeO2 cathode achieves a capacity retention of 85.3% after 500 cycles at 1C and a high-rate capacity of 124.8 mAh g-1 at 10C. This CeO2 NP pinning structure offers a novel practical strategy for designing durable high-voltage layered cathodes.