Study on Synergistic Modification of Mn‐Based Oxides by Co‐Doping with Fe and Nb and Their Lithium Storage Performance

ABSTRACT Lithium‐ion batteries are pivotal in modern energy storage systems for their environmental friendliness, high energy density and excellent cycling stability. Mn‐based compounds are highly promising anodes for them due to ultrahigh theoretical specific capacity, favorable low conversion potential and tunable electrochemical properties, yet face practical challenges of insufficient structural stability and sluggish charge transfer kinetics. Herein, a Fe─Nb dual‐element synergistic modification strategy is proposed: Fe elevates the initial specific capacity via its high theoretical capacity, while Nb reinforces structural stability and cycling retention. Using MnO 2 , Fe 2 O 3 and Nb 2 O 5 as raw materials, Mn─Fe─Nb composite oxide anodes with different molar ratios were synthesized by high‐energy ball milling followed by calcination. Electrochemical tests reveal the optimized Mn:Fe:Nb = 8:1:1 (Mn/Fe/Nb‐1) exhibits superior performance: a reversible capacity of 1044.53 mAh g −1 after 130 cycles, and a discharge capacity of 801.35 mAh g −1 at 1 A g −1 after 800 cycles. This confirms appropriate Fe─Nb co‐doping effectively suppresses structural collapse of Mn‐based materials and improves reaction kinetics, greatly extending cycle life and providing a novel approach for designing high‐performance lithium‐ion battery anodes.