Dual-Component Coating Enables Stable 4.6 V Cycling of High-Voltage LiCoO2 Cathodes.

Abstract

Lithium cobalt oxide (LCO) cathode materials are widely used in 3C electronic products but suffer from rapid capacity fading at high voltages (>4.2 V). We propose a synergistic LiF/ZrO2 double-coating strategy to construct a flexible-rigid intimately intermingled nano-mosaic artificial interphase on Al-doped LiCoO2 (LCO-Al), significantly improving its cycling stability. Electrochemical tests show that the modified LCO-Al@LiF/ZrO2 has an initial discharge specific capacity of 205 mAh g-1 at 4.6 V and 0.5 C, much higher than 179 mAh g-1 of unmodified LCO (BLCO); after 100 cycles, its capacity retention reaches 81.9% (vs. 63.5% of BLCO). LCO-Al@LiF/ZrO2 also exhibits 97% capacity retention at 4.55 V. Mechanism analysis reveals that this strategy not only stabilizes the electrode-electrolyte interface and suppresses high-voltage phase transition but also enhances Li+ transport kinetics and reduces battery polarization, thus providing an effective approach for developing high-voltage LCO cathodes for high-energy-density lithium-ion batteries.