Precise reduction of spent Li-ion battery cathode and new phase transition mechanism by self-generated H2 to achieve dual-recycling of resources and energy

The sluggish leaching kinetics and low separation efficiency of Li/Co/Ni ions with high chemical consumption greatly hindered the recovery efficiency and cost of spent Li-ion batteries. Herein, we propose a self-generated H2 drives gradient reduction of spent cathode via surface enrichment of Li+ from retired Li-ion batteries, achieving a facile, efficient extraction of Li (>99.3%) by water as a leaching agent without chemicals. Characterizations and calculations reveal the adsorption and electron transfer mechanism between H2 and LiCoO2, the new phase transition mechanism of the layered structure and the changes in the electronic bonding and coordination environment of elemental Co during H2 precise reduction. Economic and environmental analyses showed that this work exhibits 22.6% energy consumption with 0% CO2 emissions and chemical consumption than hydrometallurgy, respectively, fully demonstrated its green and energy saving prospects for recycling spent Li-ion batteries.