Mechanochemistry-induced recycling of spent lithium-ion batteries for synergistic treatment of mixed cathode powders

Efficient and sustainable recycling of metal resources from spent lithium-ion batteries (LIBs) has been attracting increasing attention, while the overwhelming dependency on chemicals and energy of the currently prevailing spent LIB recycling technologies makes it vulnerable to secondary contaminations. Herein, a mechanochemistry-based process was proposed to recover metals from waste cathode materials of LiCoO2 (LCO) and LiFePO4 (LFP) in spent LIBs based on their intrinsic redox properties. During the mechanochemical reactions, the crystal structures of LCO and LFP were destroyed and converted into amorphous states, with the synchronous generation and conversion of waste cathode materials into their recyclable states under the optimized experimental conditions of molar ratio (LCO : LFP) - 1 : 1, milling time - 5 h, rotation speed - 650 rpm and ball-powder ratio - 50 : 1. Then, 99.9% of Li and 88.6% of Co can be selectively extracted from FePO4 enriched leaching residues using a stoichiometric acid dosage of 0.15 M H2SO4. The deintercalation of Li from different waste cathode materials and in situ conversion of Co(iii)/Fe(ii) into CoO/FePO4 were further confirmed by DFT calculation results. Additional reductants/oxidants were avoided by this mechanochemistry-based strategy with significantly reduced consumption of chemicals, engineering a green and efficient recycling process for the simultaneous recycling of different metals from spent LIBs.

Automated summary

This study proposes a mechanochemistry-based process to efficiently recover metal resources from waste cathode materials of spent lithium-ion batteries (LIBs). The mechanochemical reactions destroyed the crystal structures of the waste cathode materials and converted them into amorphous states, allowing for the synchronous generation and conversion of recyclable materials under optimized experimental conditions. Using a stoichiometric acid dosage, a high selectivity in the extraction of Li and Co from leaching residues was achieved. The study demonstrates a green and efficient recycling process for different metals from spent LIBs.