Dual Strategy of LiNbO 3 Coating and Nb Doping of Li‐ and Mn‐Rich Cathode Materials: Suppressing Surface Degradation and Enhancing Rate Capability

Li‐ and Mn‐rich layered (LMRL) oxide cathode materials are among the most promising candidates for next‐generation lithium‐ion batteries (LIBs) due to their high specific capacity and cost‐effectiveness. However, their commercialization remains limited by several intrinsic challenges, including poor rate capability, surface‐side reactions stemming from oxygen release during initial cycling, and subsequent voltage fading, all of which contribute to battery performance degradation. Addressing these limitations is essential to achieving improved electrochemical performance and cycling stability. In this study, we introduce a hybrid surface modification strategy involving LiNbO 3 coating and partial Nb ion doping, applied to Li 1.13 Mn 0.57 Ni 0.30 O 2 cathodes via polydopamine (PDA)‐assisted deposition. Characterization by XPS, XRD, and TEM confirms the formation of a uniform LiNbO 3 coating and a gradient distribution of Nb dopants near the inner surface region of the LMRL structure. This dual‐modification strategy approach (coating and doping) for LMRL cathodes effectively enhances electrochemical performance, including fast‐charging behavior, extended cycling stability, and high coulombic efficiency (CE). Furthermore, the modified cathodes exhibit enhanced thermal stability under high state‐of‐charge (SOC) conditions. These findings offer a valuable pathway for the development of cathode materials capable of simultaneously mitigating side reactions and improving rate capability in LMRL cathode materials during electrochemical processes.