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

Abstract

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 LiFePO 4 (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.

Built-in electric fields and extra electric fields in the oxygen evolution reaction

“…1–6 As fossil fuel reserves gradually deplete and their combustion causes severe environmental pollution, the search for clean and sustainable energy alternatives has become particularly urgent. 7–9 Hydrogen energy, as an efficient and clean source of energy, is considered key to the future energy transition due to its excellent energy density and environmental friendliness.…”