Synergistic lattice–interface stabilization in multi-cation doped LiMn2O4 for advanced Lithium-ion batteries

Despite extensive efforts to enhance the electrochemical performance of spinel LiMn 2 O 4 (LMO), the intrinsic Jahn-Teller effect and Mn dissolution still limit its high-rate and long-cycle applications. Here, we propose a multi-cation synergistic regulation strategy using Ni-Co-Al co-doping to simultaneously stabilize the bulk lattice and interface of LMO. The three dopants play complementary roles: Ni 2+ elevates the average Mn valence and activates redox couples, Co 3+ enhances electronic and ionic conductivity, while Al 3+ strengthens the Mn O framework through high-bond-energy Al O interactions. Structural and interfacial analyses reveal that the co-doping increases the Mn 4+ fraction from 41.51% to 52.12% and reduces residual alkali species on the surface, thereby mitigating side reactions and suppressing lattice distortion. The optimized sample (LNCAMO-3) demonstrates a high discharge capacity of 103.98 mAh g −1 with 87.11% retention after 200 cycles at 1C, and maintains 85.34 mAh g −1 even at 10C. More importantly, electrochemical kinetics analyses (CV, EIS and GITT) confirm accelerated Li + diffusion and reduced charge-transfer resistance, attributed to the cooperative lattice–interface stabilization effect. This work establishes a mechanistic understanding of multi-cation synergy in spinel cathodes and offers a general design principle for developing high-rate, long-life LiMn 2 O 4 -based materials.