Recycling graphite from waste aluminium smelter Spent Pot Lining into lithium-ion battery electrode feedstock

Abstract

There is an urgent need for alternative sources of graphite, to satisfy the demands of a number of industries, including use in lithium-ion battery production. Spent potlining (SPL) represents an attractive potential source of such graphite, but requires detoxification to allow valorisation of its carbonaceous fraction. We present here a simple decontamination process for SPL, based on two-stage caustic/acidic leaching, and demonstrate how the recovered graphite may be fabricated into Li-ion electrodes. The recycled batteries are assessed against a commercial equivalent and it is found that the charge capacity increases with the thoroughness of decontamination treatment. The specific capacity of the recovered graphite is seen to compete with commercial graphite in terms of charge capacity retention. However, some residual contamination may contribute towards instability in the formed solid electrolyte interface (SEI) which requires future resolution. Overall, the potential of SPL-derived graphite to be employed in this remit is significant and has far-reaching consequences for the economics of the aluminium industry, raw material sustainability and a low-carbon economy.