A 3D continuous mesoporous carbon framework enhances electronic/ionic kinetics of LiMn0.6Fe0.4PO4 cathode for high-performance lithium-ion batteries

LiMn 1- x Fe x PO 4 (0 < x  < 1), an olivine-type cathode material, is attracting attention due to its higher voltage and energy density. However, it is plagued by relatively low electronic and ionic kinetics. In this research, we successfully fabricated a three-dimensional (3D) continuous mesoporous carbon framework embedded with ultrafine LiMn 0.6 Fe 0.4 PO 4 /C nanoparticles (LMFP/C@MC) by introducing glucose, PEG2000, and oleic acid as composite carbon sources during the synthesis process. The ultrafine LiMn 0.6 Fe 0.4 PO 4 nanoparticles shorten electron/ion transport pathways in the bulk phase and alleviate the voltage decay caused by the structural strain resulting from the Li + insertion/extraction process. The 3D continuous carbon framework provides rapid pathways for electron transport among the particles, thereby enhancing electronic kinetics, while also adapting volume changes and preventing the agglomeration of LiMn 0.6 Fe 0.4 PO 4 nanoparticles during the charge-discharge cycling. Mesopores facilitate electrolyte penetration and Li + diffusion, thereby enhancing ionic kinetics. Due to such advantages, LMFP/C@MC exhibits an ultrahigh specific capacity of 164.69 mA h g −1 at 0.1C, an excellent rate capability of 139.79 mA h g −1 at 20 C, and cycling stability with an ultrahigh retention of capacity of 96.2 % after 500 cycles at 2 C at 25 °C. Even at 60 °C, LMFP/C@MC maintains a capacity retention rate of 96 %, significantly higher than that of commercial LiMn 0.6 Fe 0.4 PO 4 /C (C-LMFP/C, 77 %) after 500 cycles at 2 C. This study presents a possible approach to developing high-performance lithium-ion battery cathodes.