Sulfion oxidation assisting self-powered hydrogen production system based on efficient catalysts from spent lithium-ion batteries.

Converting spent lithium-ion batteries (LIBs) and industrial wastewater into high-value-added substances by advanced electrocatalytic technology is important for sustainable energy development and environmental protection. Here, we propose a self-powered system using a home-made sulfide fuel cell (SFC) to power a two-electrode electrocatalytic sulfion oxidation reaction (SOR)-assisted hydrogen (H) production electrolyzer (ESHPE), in which the sulfion-containing wastewater is used as the liquid fuel to produce clean water, sulfur, and hydrogen. The catalysts for the self-powered system are mainly prepared from spent LIBs to reduce the cost, such as the bifunctional CoS catalyst was prepared from spent LiCoO for SOR and hydrogen evolution reaction (HER). The Fe-N-P codoped coral-like carbon nanotube arrays encapsulated FeP (C-ZIF/sLFP) catalyst was prepared from spent LiFePO for oxygen reduction reaction. The CoS catalyst shows excellent catalytic activities in both SOR and HER, evidenced by the low cell voltage of 0.426 V at 20 mA cm in ESHPE. The SFC with CoS as anode and C-ZIF/sLFP as cathode exhibits an open-circuit voltage of 0.69 V and long discharge stability for 300 h at 20 mA cm. By integrating the SFC and ESHPE, the self-powered system delivers an impressive hydrogen production rate of 0.44 mL cm min. This work constructs a self-powered system with high-performance catalysts prepared from spent LIBs to transform sulfion-containing wastewater into purified water and prepare hydrogen, which is promising to achieve high economic efficiency, environmental remediation, and sustainable development.