Ultra-fast leaching of critical metals from spent lithium-ion batteries cathode materials achieved by the synergy-coordination mechanism

Poor economics is the principal factor that hinders the commercialization of hydrometallurgy processing of spent lithium-ion batteries cathode materials. Here, ultra-fast leaching of spent cathode materials (97.72% Li and 97.25% Co leached under S/L ratio: 10 g/L, temperature: 363 K within 10 min) was achieved in 0.5 M hydrochloric acid and 0.5 M L-ascorbic acid system as part of reducing the costs of hydrometallurgy process. The correlations of both acids with the leaching ratios were studied for the first time with the Pearson correlation coefficient. The mixture of 0.5 M hydrochloric acid and 0.5 M L-ascorbic acid demonstrated both faster kinetics and higher leaching volume than those of aqua regia. Adopting quantum chemistry and thermodynamic calculations, four hypothetical mechanisms were proposed to interpret the reaction mechanisms. Synergy-coordination, with the lowest energy, was considered to be the most reasonable mechanism for the leaching of cathode materials. Three scenarios with different leaching systems and conditions were compared to identify the key parameters determining the economics of the leaching process.