Lithium-rich manganese-based cathodes are promising for high-energy-density lithium-ion batteries but are hindered by poor cycling stability and rate capability. This study demonstrates that synergistic Zn2+ doping and Al2O3 coating effectively enhance their electrochemical performance. Structural analyses reveal that moderate Zn doping (LNCM@Zn2) expands the (003) interplanar spacing from 0.47 nm to 0.496 nm, lowers Li+ diffusion barriers, and suppresses transition-metal cation mixing. These modifications yield an initial discharge capacity of 276.4 mAh g-1 at 0.1C with improved rate performance. However, excessive doping (LNCM@Zn3) induces lattice overexpansion, causing structural instability and capacity fade. Concurrently, the Al2O3 coating acts as a protective layer, mitigating structural degradation and enhancing interfacial conductivity. The dual-modified Zn-doped and Al2O3-coated LNCM exhibits significantly enhanced cycling stability and superior high-rate capability compared to pristine materials. Optimal performance is achieved with the co-modified LNCM@Zn2@Al2O3, which maintains high discharge capacity at high current densities due to the combined benefits of the stabilized bulk structure (Zn doping) and protected surface (Al2O3). These results establish Zn doping coupled with Al2O3 coating as a viable strategy for developing high-performance LNCM for next-generation batteries.
Wang et al. (Thu,) studied this question.