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

Abstract

The sluggish leaching kinetics and low separation efficiency of Li/Co/Ni ions, along with high chemical consumption, significantly hinder the recovery efficiency and increase the cost of spent Li-ion batteries. Herein, we proposed a self-generated H₂-driven gradient reduction of spent cathodes via surface enrichment of Li⁺ from retired Li-ion batteries, achieving a facile and efficient extraction of Li (>99.3%) using water as the sole leaching agent, without additional chemicals. Characterizations and calculations revealed the adsorption and electron transfer mechanisms between H₂ and LiCoO₂, a new phase transition mechanism of the layered structure, and changes in the electronic bonding and coordination environment of elemental Co during precise H₂ reduction. Economic and environmental analyses showed that this work exhibited 22.6% of the energy consumption (20.9 kW h kg⁻¹ Li), with 0% CO₂ emissions and chemical consumption compared to hydrometallurgy, fully demonstrated its green and energy-saving potential for recycling spent Li-ion batteries.