Based on N, F, and P co-doping biomass carbon to construct 3D porous carbon coated LiFePO4 for preparing lithium-ion batteries

Because of its superior structural stability, high level of safety, and low cost, the olivine-type LiFePO4 (LFP) is a prevailing cathode material in lithium-ion batteries. However, its development is constrained to inferior electronic conductivity and sluggish diffusion kinetic. In this work, a biomass carbon source derived from microbial residue was introduced to modify LiFePO4 (LFP@NFPC). LFP@NFPC composite with three-dimensional (3D) porous structure was synthesized via a facile wet ball milling and high-temperature calcination. Through well-designed experiment and feasible data analysis, a high conductive 3D network structure is constructed by N, F, and P co-doped carbon coating in the surface of LiFePO4, facilitating fast electron transport and rapid reaction kinetics bewteen intercrystalline. Meanwhile, the LFP@NFPC with three-dimensional (3D) porous structure can also improve the accessibility of Li+ over a protrcated cycle. The as-prepared LFP@NFPC shows discharge specific capacities of 168.2, 138.4, and 103.8 mAh/g at 1, 10, and 50C, respectively. Simultaneously, the LFP@NFPC||Graphite full battery indicates a specific capacity of 161.2 mAh/g at 1C, thus exhibiting superior rate capacity and outstanding cycle stability. This work provides a sustainable and economical approach to modify the cathode material of LIBs.