Waste is the best: end-of-life lithium ion battery-derived ultra-active Ni3+-enriched β-Ni(OH)2 for the electrocatalytic oxygen evolution reaction

Urban mining of e-waste, especially end-of-life lithium ion batteries (LIBs), is gaining momentum as a potential secondary source for valuable metals and due to the environmental impact associated with their disposal. Utilization of these metals in renewable energy-related applications could cater to the realization of a circular economy by reusing industrial waste for sustainable applications. In this regard, we explore the formation of Ni3+-enriched beta-Ni(OH)(2) from spent LIBs and analyze its efficacy as an electrocatalyst for the oxygen evolution reaction (OER). As-synthesized beta-Ni(OH)(2) requires a minimal overpotential of 300 mV to reach a current density of 50 mA cm(-2) with a low Tafel slope of 42.7 mV dec(-1). The usual sluggish kinetics of the OER is mitigated due to the strategic presence of a small amount of NiOOH, and surface oxygen vacancies. In situ impedance analysis strongly supports the improved OER performance of Ni3+-rich beta-Ni(OH)(2) due to facile OH* adsorption followed by rapid charge transfer at the electrode-electrolyte interface. The combined effect is manifested in ultrafast OER with mass activity 1044 mA mg(-1) and TOF 257.2 s(-1), which are exceptional for Ni-containing systems. The structural integrity of the catalyst was validated with post-OER characterization experiments, delineating the applicability of e-waste-derived materials for renewable energy applications.