A new approach to regenerate high-performance graphite from spent lithium-ion batteries

Abstract

With the increasing use of lithium-ion batteries in our life and industrial production, more attention has been focused on the recycling of waste lithium-ion batteries. The recovery of transition metal elements from the cathodes has attracted widespread attention, but the recovery of graphite anodes has not been emphasized. In fact, to regenerate graphite with low cost technology is of great significance to solve the problem of the utilization of spent graphite and the pollution. Herein, we design a regeneration method involving pretreatment and catalytic graphitization to restore spent graphite. Specifically, using sulfuric acid for pretreatment and cobalt salt for catalyzing, our recycling technology not only improves the purity of spent graphite, but also restores the structural defects of graphite, resulting in improving its rate performance and cycle stability. The spent graphite can only provide a specific capacity of 301.1 mAh/g for the 1st cycle at 0.1 C and 79.5 mAh/g after 500 cycles at 1 C. By comparison, the regenerated graphite shows a specific capacity of 358 mAh/g for the 1st cycle at 0.1 C and 245.4 mAh/g after 500 cycles at 1 C. At the same time, the cobalt can be recovered as cobalt salt. As a result, the entire recycling process constitutes a closed loop.