Spent Graphite—HARD Carbon Composite Anode for Sustainable and High‐Performance Lithium‐Ion Batteries

ABSTRACT Graphite is considered as the benchmark anode for lithium‐ion batteries (LIB) due to its good performance metrics. However, graphite has limitations for high‐power conditions due to safety concerns. Hard carbon (HC) represents a structurally disordered carbonaceous material that has a better rate capability and better temperature stability than graphite. This study introduces a sustainable composite anode material of regenerated spent graphite (SG) and hard carbon, distinguishing it from previously reported materials. Herein, we have systematically studied the performance of HC, the regenerated SG, and its composites HC:SG‐3:1, HC:SG‐1:1 and HC:SG‐1:3. The specific capacity of HC was 198 mAh/g compared to 301 mAh/g of SG at a rate of C/2; when these electrodes were tested at a rate of 5C, HC delivered 113 mAh/g while the SG delivered only 40 mAh/g. Also, cycling of HC, HC:SG‐3:1, HC:SG‐1:1, and SG delivered a capacity of 125, 109, 104, and 76 mAh/g respectively, at the end of the 500 ^th cycle at a 5C rate. The full‐cell performance of the HC:SG composite showed satisfactory performance with an energy density of 260 Wh/kg _a . Further, ex situ surface chemical analysis was carried out in pristine and cycled electrodes to understand the chemical changes upon cycling.