Optimum synthesis and electrochemical properties of Li2FeSiO4 cathode for lithium ion battery prepared by a molten salt assisted method

Abstract Li 2 FeSiO 4 are prepared via a simple and cost-effective molten salt method. The morphology, crystal structure and electrochemical properties are evaluated by X-ray diffraction, scanning electron microscopy, galvanostatic charge–discharge test and electrochemical impedance spectroscopy. When the molar ratio of raw FeC 2 O 4 and NaCl/KCl molten salt is 1:4 in the starting precursors, the obtained sample exhibits high purity, uniform particle size and slight aggregation. As a cathode material for lithium-ion battery, the Li 2 FeSiO 4 sample with 13.5% carbon (LFS/C-13.5%) shows an initial discharge capacities of 175.9 mA h/g, and its capacity retention can reach 80% after 65 cycles. Compared to experimental data, the molten salt assistance is a better synthetic strategy than simple solid-state reaction. It can product higher-quality Li 2 FeSiO 4 with uniform morphology and good purity.