Nano-LiFePO₄/C Derived from Gaseous-Oxidation Engineering-Synthesized Amorphous Mesoporous nano-FePO₄ for High-Rate Li-Ion Batteries

Fast charging/discharging capabilities are highly desirable for Li-ion batteries (LIBs). LiFePO₄ as a low-cost material is widely used in LIBs. However, the poor electronic and ionic conductivity hinder its rate performance. Herein, a continuous ozone-oxidation strategy is successfully used to prepare amorphous mesoporous nano-FePO₄ (O₃-FP), which is then used to synthesize high-performance nano-LiFePO₄/C (nano-LFP/C). The continuous ozone bubbles are the key to oxidize the Fe­(II) salts and restrain the aggregation of precipitated nanoparticles benefiting from the gas bubble confinement effect and a higher ζ potential. The obtained O₃-FP shows a smaller and more uniform particle size, and a larger surface area than the conventional liquid oxidation-prepared FePO₄ (FP). The O₃-FP-derived nano-LFP/C exhibits a uniform carbon coating, a smaller and more even particle size, and better electrochemical performance. When used as cathode for LIBs, the optimized electrode delivers a high capacity of 160 mAh g^–1 at 1C and 78 mAh g^–1 at an ultrahigh rate of 150C. Moreover, it also possesses excellent high- and low-temperature performance. The uniform-carbon-coating nano-LFP/C developed in this research is simple, scalable, and environmentally benign, making it promising for mass production of nano-LFP/C.