Tribocatalytic recycling of lithium-ion batteries

Abstract

To explore recycling solutions for used lithium-ion batteries (LIBs), a tribocatalytic method is proposed in this paper. When ZnO nanoparticles were used as catalysts, the leaching rates of lithium and cobalt in lithium cobaltate batteries reached 95% and 84%, respectively. In Li–Co–Mn–Ni batteries, the leaching rates of lithium, cobalt, manganese, and nickel were 96.61%, 90.00%, 76.06%, and 61.78%, respectively. In the acid leaching system, the lowest unoccupied molecular orbital (LUMO) and the highest occupied molecular orbital (HOMO) of citric acid (CA) were in more appropriate positions, indicating that CA is more prone to redox reactions when rubbed on the surface of zinc oxide. Compared with H2O, CA is more electrostatically polarized and can participate in more reactions through electron transfer on the ZnO surface. First-principles calculations of the adsorption energies show that the interactions are stronger when CA molecules are located on the lithium cobalt oxide (LCO)(110) surface. The combination of theoretical calculations and experiments verified that the tribocatalytic weak acid leaching process is an effective ion leaching scheme. The free radicals generated during the catalytic process promoted the leaching of metal ions, thus enabling the recycling of cathode materials for lithium-ion batteries. In addition, this method has great potential for the reduction and leaching of ions.