Harnessing Regenerated Graphite from Spent Lithium-Ion Batteries to Enhance the Performance of Sulfur Cathode in Lithium-Sulfur Batteries

In this work, a facile hydrometallurgical approach combined with heat treatment has been adopted to recycle spent graphite from retired lithium-ion battery cells. Graphite regenerated with 18 M H2SO4 leaching leads to a high specific surface area, significant porosity and small crystallite size. The regenerated graphite has been infiltrated with sulfur under solvothermal conditions at 160 °C. The sample containing 68 wt % of sulfur recovers a capacity of 224 mAh/g after 100 cycles. Furthermore, the electrode with a higher sulfur content of 84 wt %, recuperates the specific discharging capacity of 207 mAh/g after 100 cycles. After the initial fading during the first 5–10 cycles, the cathodes based on regenerated graphite demonstrate stable cycling behavior. This research not only offers an accessible and scalable method for regenerating graphite from spent LIBs but also demonstrates a new application of the regenerated graphite in LSBs, showcasing outstanding electrochemical performance.