Constructing novel hydrated metal molten salt with high self-healing as the anode material for lithium-ion batteries

Abstract

Lithium-ion batteries (LIBs) are greatly limited in their practical application because of their poor cycle performance, low conductivity and volume expansion. Herein, molten salts (MSs) FeCl₃·6H₂O–NMP with low temperature via simple preparation are used as the anode material of LIBs for the first time to break through the bottleneck of LIBs. The good fluidity and high self-healing of FeCl₃·6H₂O–NMP effectively avoid the collapse and breakage of the structure. Based on this feature, the initial discharge specific capacity reached 770.28 mA h g⁻¹, which was more than twice that of the commercial graphite anode. After 200 cycles at a current density of 100 mA g⁻¹, the specific capacity did not decrease rather it was found to be higher than the initial discharge specific capacity, reaching 867.24 mA h g⁻¹. Besides, the good conductivity of MSs provides convenience for the removal and intercalation of Li⁺. The active H sites that can combine with lithium ions form LiH and provide capacity for LIBs. Density functional theory (DFT) calculation also provided theoretical proof for the mechanism of LIBs.