Boosting High-Temperature Durability of Industrial-Scale LiMn_0.6Fe_0.4PO₄ 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-<i>x</i>Mn_0.6Fe_0.4Nb_<i>x</i>@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.