A hydrothermally synthesized LiFePO_4/C composite with superior low-temperature performance and cycle life

摘要

Highlights•The LiFePO4/C composites are synthesized by a hydrothermal process.•The derived carbon coating is uniform with high crystallization degree.•The carbon coating improves the electronic conductivity and specific capacity.•The LiFePO4/C demonstrates excellent low-temperature and cycling performance.AbstractThe LiFePO4/C composites have been successfully synthesized by a hydrothermal process, with the combined carbon sources of fructose and calcium lignosulfonate. The morphology and microstructure of LiFePO4/C were investigated by X-ray diffraction, scanning electron microscopy, transmission electron microscopy and Fourier transform infrared spectroscopy. The electrochemical properties were evaluated by the constant-current charge/discharge tests, cyclic voltammetry and electrochemical impedance spectroscopy. The uniform carbon coating layer derived from calcium lignosulfonate can effectively improve the electronic conductivity, lithium-ion diffusivity and surface stability of the LiFePO4/C composites and prevent the side reactions between the LiFePO4particles and electrolytes. The LiFePO4/C composites display excellent rate capability, superior cycle life and outstanding low temperature performance, which are promising for lithium-ion battery applications in electrical vehicles and electrical energy storage systems.