Surfactants assisted synthesis and electrochemical properties of nano-LiFePO4/C cathode materials for low temperature applications

Nano-LiFePO4/C cathode materials have been synthesized by a solid-state reaction method using Tween60-Span60 composite as surfactant and carbon source. The Tween60-Span60 composite surfactants together lead a strong space steric effect, which ensures a high surface energy and reaction kinetic of the precursors. Consequently, it contributes to the formation of uniformly distributed LiFePO4 particles coated with a thin layer of carbon. The unique structured LiFePO4/C cathode materials can deliver high electrochemical capacities of 166, 150.5 and 130.1 mAh g−1 under 0.1 C at 25, 0 and −20 °C, respectively. Moreover, the LiFePO4/C cathode materials demonstrate an excellent rate capability and cycle performance, no discernible specific discharge capacity fading has been observed after over 400 cycles under the rate of 0.1-5 C at 25 °C, or after over 100 cycles under the rate of 0.1-0.5 C at −20 °C.