Redox-Mediated Recycling of Spent Lithium-Ion Batteries Coupled with Low-Energy Consumption Hydrogen Production

Electrochemical recycling of spent lithium-ion batteries (sLIBs) is potentially cost-effective and consumes fewer chemicals than traditional metallurgical processes. However, severe side reactions and low system durability limit its practical applications. Herein, a redox-mediated electrochemical recycling strategy was developed for continuous Li extraction from spent LiFePO4 (sLFP), coupled with low-energy-consumption hydrogen production. Phosphomolybdic acid (PMA) was employed as a green redox mediator to achieve fast and selective Li extraction from sLFP, and the reduced PMA was instantaneously electro-regenerated for subsequent extractions. In the assembled electrochemical flow cell, the Li recovery efficiency reached 97.8%, and the Faradaic efficiency of the hydrogen evolution reaction was approximately 100%. Furthermore, the redox-mediated sLFP-hydrogen coupling system required only 0.5 V of cell voltage to produce hydrogen, significantly lower than that of ∼1.65 V in the traditional water splitting process. This work presents a promising and sustainable route for the simultaneous recycling of sLIB and production of clean hydrogen fuels.