Orbital Engineering via D‐p Hybridization by in Doping Enables High‐Performance Lithium Manganese Iron Phosphate Cathodes

ABSTRACT Lithium manganese iron phosphate (LMFP) is a promising cathode material for lithium‐ion batteries, featuring high theoretical energy density, low cost, and excellent safety. However, the practical application of LMFP cathode material is critically limited by their inherent poor electronic conductivity and structural degradation during cycling. To address these bottlenecks, we reported a rational design of an indium (In)‐doped LMFP material. Comprehensive characterizations confirm the successful incorporation of In 3+ into the olivine lattice, which induces a slight lattice expansion while maintaining the particle morphology. Crucially, In doping effectively suppresses the Jahn–Teller distortion and mitigates transition metal dissolution. The optimized LiMn 0.5 Fe 0.49 In 0.01 PO 4 cathode exhibits superior rate capability (157 mAh/g at 0.1C and 125 mAh/g at 5C) and outstanding cycling stability, with nearly zero capacity decay after 300 cycles at 1C. Electrochemical impedance spectroscopy and post‐cycling analysis reveal that the enhanced performance originates from reduced charge‐transfer resistance, accelerated reaction kinetics due to increased electron delocalization, and effective suppression of structural degradation and interfacial side reactions. This work establishes In doping as a potent strategy for concurrently enhancing the electronic conductivity and structural integrity of LMFP cathodes. The successful demonstration of kilogram‐scale synthesis underscores the industrial viability of this approach, thereby paving the way for developing advanced cathode materials toward high‐power and long‐life energy storage.