LiFePO4/C composites with high compaction density as cathode materials for lithium-ion batteries with high volumetric energy density

To further improve the volumetric energy density of LiFePO4 based cathode materials, herein, lithium iron phosphate supported on carbon (LiFePO4/C) with high compaction density of 2.73g/cm3 has been successfully synthesized by elaborate controlling the particle size of precursor slurry and the resultant LiFePO4/C composite. The as-synthesized composite is demonstrated to be an attractive positive electrode candidate for lithium-ion batteries, and the capacity of 18650 cell with LiFePO4/C as cathode reaches 7.0 Wh. Furthermore, high-/low-temperature discharge performance and reversibility of capacity retention are excellent. XRD patterns show that LiFePO4/C with higher compaction density exhibited better crystallinity corresponding to olivine structure. Electrochemical impedance spectroscopy (EIS) tests demonstrate that high compaction density of the cathode materials is beneficial for electrochemical property promotion. The as-synthesized LiFePO4/C is a promising candidate for the development of high-performance, cost-effective lithium-ion batteries for electric vehicles, and this work provides a feasible way to synthesize LiFePO4/C composite with high compaction density and excellent electrochemical performance.