Recycling spent carbon cathode by a roasting method and its application in Li-ion batteries anodes

Spent carbon cathode (SCC), a hazardous solid waste produced from aluminum reduction, limits the sustainable development of the aluminum industry. This study presents a roasting treatment for removing impurities to achieve the recycling of SCC and the recycled SCC is applied as the anode of Li-ion batteries (LIBs). The effect of the roasting technologies on the carbon content of the SCC was studied, and the results show that the impurities in the SCC can be gradually removed as the temperature increases. The carbon content of the SCC can reach 97.22 % under the optimum parameters, which includ a roasting temperature of 1600 °C, roasting time of 1 h and particle size of 200 mesh. Compared to graphite and SCC, SCC treated at 1600 °C (SCC-1600) as the anodes of Li-ion batteries exhibits a good reversible capacity of 365.5mAh g−1 at 0.1 C after 100 cycles with a decay rate per cycle of 0.028 %. SCC-1600 displays an impressive performance with a reversible capacity of 235.0 mAh g−1 at 1 C after 500 cycles. Recycling SCC as a low-cost material for the anodes of LIBs provides a feasible solution for the efficient disposal of other hazardous carbonaceous solid wastes. •Spent carbon cathode can be sufficiently recycled by the roasting method.•The impurities were removed and the carbon content exceeded 96 % by the roasting method.•SCC-1600 with unique structure is investigated for the first time as anode of LIBs.•The capacity and cycle performance of SCC-1600 are superior to those of graphite.