Selective lithium extraction of cathode materials from spent lithium-ion batteries via low-valent salt assisted roasting

The efficient recovery of lithium from spent lithium-ion batteries has attracted extensive attention due to serious restriction of sustainable development of the lithium-ion battery industry caused by shortage and high price of lithium resources. The current traditional process faces high energy consumption and low benefit, which is not conducive to the industrial reform of selective lithium extraction from spent lithium-ion batteries. Herein, we propose a novel selective lithium extraction process through low-valent salts assisted roasting and washing to achieve the closed-loop recycling of spent cathode materials. The leaching rate of lithium reach 99.39% under the optimized conditions of the molar ratio of low-valent salts to spent LiCoO2 materials of 3.0 and roasting temperature of 750 ℃ for 40 min. The key to the successful application of low-valent salts assisted roasting process relay on the conversion of insoluble polysulfides achieved by controlling the disproportionation reaction of cobalt with the aid of low valent salts. The regenerated LiCoO2 materials display excellent structure and electrochemical performance with initial discharge specific capacity of 155.5mAh/g at 0.1C and the capacity retention rate 93.89% after 100 cycles. The remarkable economic and environmental benefits of the low-valent salts assisted roasting process provide support for practical industrial innovation and application of recycling of spent lithium-ion batteries.