Boosting High-Temperature Durability of Industrial-Scale LiMn0.6Fe0.4PO4 Cathode through Niobium Doping

Renewable energy’s growth of renewable energy drives the need for advanced lithium-ion batteries (LIBs). LiMn_0.6Fe_0.4PO₄ (LMFP) cathode materials show promise but face challenges like the Jahn–Teller effect and metal dissolution, undermining structural stability and cycling performance, especially under elevated temperatures. This study pioneers the strategic doping of high-valence niobium (Nb⁵⁺) into LMFP to address these limitations. The Nb-doped LMFP cathodes were synthesized at an industrial scale using industrially viable coprecipitation and spray-drying methods. Nb is doped into the Li site with controllable atomic content from 0 to 3%. The introduction of Nb reduces antisite defects, accelerates lithium-ion diffusion, and effectively suppresses both the Jahn–Teller effect and manganese dissolution. Notably, the optimized Li_1–xMn_0.6Fe_0.4Nb_x@C cathode with 2% Nb exhibits remarkable high-temperature performance, retaining 95.07% of its capacity over 150 cycles at 60 °C and delivering a discharge capacity of 148.4 mAh g^–1. These results underscore the transformative potential of Nb doping in overcoming thermal degradation, offering a compelling pathway for the development of robust, long-life LIB cathodes.