Extra Li-ion storage of LiFePO4/C composite materials synthesized with Fe1.5P

Abstract The high-capacity lithium iron phosphate composite (LiFePO4/C) materials were synthesized via the method of hydrothermal and high temperature solid phase with Fe1.5P as main source of Fe and P. Electrochemical analysis shown that the LiFePO4/C synthesized by 3.6 g L−1 cetyltrimethylammonium bromide (CTAB) assisted (LFP/C–C2.0) had the discharge specific capacity of 174.5 mAh/g at 0.1C, and had the discharge specific capacity of 137.09 mAh/g after 50 cycles at 1C, corresponding capacity retention rate maintained 96.8%. LFP/C–C2.0 exceeded the theoretical specific capacity of LiFePO4 (170 mAh g−1), and LiC6, Fe and Li0.91(Fe0.403Fe0.387Mn0.21)PO4 could be detected, which all affected the electrochemical performance of this material and brought new methods of Li-ion storage for this material.