Perovskite Li 3/ 8 Sr 7 / 16 Ta 3 / 4 Zr 1 / 4 O 3 Surface Coating Enables Stable Cycling of Li‐Rich Mn‐Based Cathodes at High Voltage

Li‐rich Mn‐based layered oxides are recognized as cathode materials with bright prospects for rechargeable lithium‐ion batteries (LIBs), primarily attributed to their low cost, high capacity output, and high operating voltage. However, their practical application is restricted by inadequate initial Coulombic efficiency (ICE) and unstable electrode/electrolyte interfaces, which result in high interfacial impedance, large overpotential, irreversible capacity fading, and inferior cycling stability. In this work, Li 3/8 Sr 7/16 Ta 3/4 Zr 1/4 O 3 (LSTZ), a fast Li + ‐ion conductor, is introduced as a surface coating. The LSTZ layer effectively suppresses oxygen release and electrolyte corrosion, thereby mitigating structural degradation and voltage decay while improving interfacial stability. Moreover, LSTZ provides fast Li + transport pathways, facilitating Li + diffusion, and reducing polarization, which significantly enhances rate capability. At 1 C and 25 °C, the LSTZ‐coated cathode delivers a reversible capacity of 178.5 mAh g −1 with 94.4% retention after 120 cycles. Even at 0.3 C and 45 °C, it maintains 209.7 mAh g −1 with 95.7% retention after 300 cycles, demonstrating excellent thermal stability.