Prelithiated FeS2 cathode with alleviated volume expansion toward improved cycling performance

Abstract

Abstract FeS2 has been widely studied and is considered as a promising Li-free cathode for the next generation high-energy-density lithium metal batteries. However, it has a fast capacity decay due to large volume expansion. Herein, with the aim to pre-expand the particle, a mild chemical prelithiation strategy is applied to obtain LixFeS2 cathode. It alleviates the electrode s volume variation during cycling process by keeping a well electrical contact between the conductive additive and the active material. In addition, partially amorphous Li2S, generated in situ by the reaction of FeS2\xa0+\xa04Li-Bp\xa0→\xa0Fe\xa0+\xa02Li2S\xa0+\xa04Bp, achieves rapid interfacial Li+ transportation and low solubility of polysulfides. As a result, the prelithiated FeS2 electrode material exhibits an alleviated volume variation and an improved cycling performance. This work can be extended to other conversion reaction materials with large volume expansion for better electrochemical performance.