A high-performance nano-Sn/G@C composite anode prepared by waste carbon residue from spent Lithium-ion batteries

The high-value utilization of waste carbon residue (WCR) from spent lithium-ion batteries (LIBs) enjoys great significance in environmental protection and economic growth. Here, a nano-SnO2/Graphite (nano-SnO2/G) precursor is synthesized with SnCl2 as the reducing agent by utilizing the defect characteristics indicating that the WCR surface has been severely oxidized and presented a porous structure. Firstly, the roasting conditions are optimized by the combination of orthogonal and single-factor experiments. The results showed that the nano-SnO2/G precursor with 41.41 % Sn loading is obtained via the molten-salt method under optimal conditions, and 99.97 %, 99.93 %, 99.93 %, 99.45 %, 95.89 %, and 97.83 % of Ni, Co, Mn, Al, Si, and Fe in the WCR can be removed. Subsequently, the mechanisms of microscopic atomic reactions in the molten-salt roasting are explored by the density functional theory simulations. Finally, the high-performance nano-Sn/[email protected] composite anode with a sandwich structure is prepared via carbothermal reduction. It exhibited a high initial Coulombic efficiency of 85.09 % and a reversible specific capacity of 650.9mAh/g at 100 mA/g. Moreover, the nano-Sn/[email protected] displayed ultra-stable cycling with a capacity fading rate of 0.034 % per cycle and reserved a high reversible specific capacity of 607.6mAh/g at 500 mA/g after 500 cycles. The proposed process represents a remarkable advancement in regenerating WCR into higher-value applications.