Enhanced charge storage of Li3FeF6 with carbon nanotubes for lithium-ion batteries

Abstract

Due to stability in the air, easy preparation process, lower cost and high reaction potential, Li₃FeF₆ is a promising cathodic material in lithium-ion batteries. However, the poor electronic conductivity of Li₃FeF₆ limits its performance in lithium-ion batteries. Conductive agent addition can improve the electronic conductivity of Li₃FeF₆ composite electrodes. The specific capacity of the Li₃FeF₆/C electrode is around 80 mA h g⁻¹ (the highest value), corresponding to 0.57 Li⁺ embedding. While a specific capacity of the Li₃FeF₆/CNTs electrode of 120 mA h g⁻¹ can be achieved, which is close to the theoretical capacity (140 mA h g⁻¹), and the reversible capacity can be maintained at above 100 mA h g⁻¹ after 50 cycles, with a capacity retention of 83%, which indicates greater electrochemical activity for such a CNT containing electrode. The enhanced performance of the Li₃FeF₆/CNTs electrode is due to the lower interface resistance and improved electrochemical activity of the Li₃FeF₆ active material.