The Direct Application Of Spent Graphite As A Functional Interlayer With Enhanced Polysulfide Trapping And Catalytic Performance For Li-S Batteries

Recycling and reusing spent graphite have become urgent tasks, with massive numbers of lithium-ion batteries (LIBs) from hybrid electric vehicles (HEVs)/electric vehicles (EVs) retired every year. Meanwhile, interlayer designs based on carbon materials have attracted widespread attention to suppress the polysulfide shuttle effect in high-energy-density lithium-sulfur (Li-S) batteries. Nevertheless, designing simple and low-cost carbon-derived interlayers still remains a great challenge. Spent graphite possesses a porous structure, defects, and polar functional groups that were formed in situ, which can significantly confine polysulfides through a combination of physical and chemical adsorption. Meanwhile, transition metals introduced due to the dissolution of cathode active materials can also anchor polysulfides via S-TM bonding, as well as improving electrical conductivity and boosting polysulfide conversion kinetics. Herein, spent graphite recycled from waste LIBs was employed for the first time as a functional interlayer for Li-S batteries based on its intrinsic properties. The spent-graphite-derived interlayer exhibited remarkably enhanced trapping and catalytic performance toward polysulfides. A high discharge capacity of 968 mA h g(-1) with a low decay rate of 0.08% per cycle over 500 cycles at 1 C can be obtained. The present work not only provides a promising strategy for the design of interlayers, but it also shows a high-value application of spent graphite.