Hybrid ion/electron interfacial regulation stabilizes the cobalt/oxygen redox of ultrahigh-voltage lithium cobalt oxide for fast-charging cyclability

High-voltage and fast-charging LiCoO_(2)(LCO)is key to high-energy/power-density Li-ion batteries.However,unstable surface structure and unfavorable electronic/ionic conductivity severely hinder its high-voltage fast-charging cyclability.Here,we construct a Li/Na-B-Mg-Si-O-F-rich mixed ion/electron interface network on the 4.65 V LCO electrode to enhance its rate capability and long-term cycling stability.Specifically,the resulting artificial hybrid conductive network enhances the reversible conversion of Co^(3+)/^(4+)/O_(2)/nredox by the interfacial ion–electron cooperation and suppresses interface side reactions,inducing an ultrathin yet compact cathode electrolyte interphase.Simultaneously,the derived near-surface Na+/Mg2+/Si^(4+)-pillared local intercalation structure greatly promotes the Li^(+)diffusion around the 4.55 V phase transition and stabilizes the cathode interface.Finally,excellent 3 C(1 C=274 mA g1)fast charging performance is demonstrated with 73.8%capacity retention over 1000 cycles.Our findings shed new insights to the fundamental mechanism of interfacial ion/electron synergy in stabilizing and enhancing fast-charging cathode materials.