Self-assembled mesoporous LiFePO4 with hierarchical spindle-like architectures for high-performance lithium-ion batteries

Self-assembled mesoporous LiFePO4 (LFP) with hierarchical spindle-like architectures has been successfully synthesized via the hydrothermal method. Time dependent X-ray diffraction, scanning electron microscopy, and cross section high resolution transmission electron microscopy are used to investigate the detailed growth mechanism of these unique architectures. Reaction time and pH value play multifold roles in controlling the microstructures of LFP. The LFP particles are uniform mesoporous spindles, which are comprised of numerous single-crystal LFP nanocrystals. As the cathode material for lithium batteries, LFP exhibits high initial discharge capacity (163 mAh g−1, 0.1 C), excellent high-rate discharge capability (111 mAh g−1, 5 C), and cycling stability. These enhanced electrochemical properties can be attributed to this unique microstructure, which will remain structural stability for long-term cycling. Furthermore, nanosizing of LFP nanocrystals can increase the electrochemical reaction surface, enhance the electronic conductivity, and promote lithium ion diffusion.

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► A growth model of hierarchical spindle-like LiFePO4 has been proposed.
► The mesoporous structure remains the structural stability for long-term cycling.
► Nanocrystals achieve higher surface area and shorter Li+ diffusion length.