Direct recycling of spent lithium-ion battery cathodes inspired by the polymerization of dopamine

Abstract

The direct recycling process shows excellent flexibility and potential for the regeneration of spent lithium-ion battery cathodes. However, conventional direct recycling methods involve high temperatures or potential secondary pollution. Herein, the green restoration of spent LiFePO4 (LFP) cathodes is achieved via a polymerization of dopamine (POD)-assisted process in water at room temperature. A unique mechanism is proposed based on DFT calculations: Some intermediates, rather than dopamine or polydopamine, restore the crystal structure of spent LFP. Furthermore, a short annealing treatment could not only increase the structural stability, but also avoid the potential secondary pollution caused by the reductants by converting the Polydopamine (PDA) layer to an N-doped carbon layer and improve the electrochemical performance of the regenerated LFP. A subsequent techno-economic analysis suggests that the present strategy promises great potential in practical application. Environmental implicationSpent lithium-ion batteries (LIBs) contain a large number of toxic and hazardous substances, which would affect ecological balance and human activities, so recycling and reuse of spent LIBs play a vital role in environmental protection. The POD-assisted recycling strategy can maximize the recycling value of the LiFePO4 cathode material, and avoid the secondary pollution caused by the reducing agent. Compared with the traditional pyrometallurgy and hydrometallurgy, the POD-assisted recycling strategy has less negative impact on the environment, higher economic value, and has a broad application prospect.