Novel and superhydrophilic bifunctional NiCuMn@TiN nanosheets supported on iron foam for high-performance supercapacitors and water oxidation

Synthesizing low-cost and highly efficient bifunctional electrocatalysts for hybrid supercapacitors and oxygen evolution reaction (OER) is critically essential for the progress of energy storage and conversion devices. Therefore, a novel, inexpensive and superhydrophilic bifunctional NiCuMn@TiN nanosheet supported on iron foam (NiCuMn@TiN/IF) is successfully designed and fabricated via spent cupronickel (SCN) as Ni and Cu precursor by a facile one-step electrosynthesis routine. With adding nano titanium nitride (TiN), the obtained NiCuMn@TiN/IF composite electrode not only possesses a large superhydrophilic surface that enhances ion/ electron transfer efficiency and provides numerous activity sites for the electrochemical reaction but also achieves efficient recovery of metal resources using the secondary resource SCN as soluble anode further reduces the cost of electrode preparation. And since the synergistic effect of large specific surface area and superhydrophilicity, the NiCuMn@TiN/IF delivers a high specific capacity of 22.5 F cm-2 at 10 mA cm-2 in 3 M KOH and also illustrates superior OER activity with an extremely low overpotential (286 mV) and remarkable durability at a high current density of 100 mA cm-2 in 1 M KOH. This research provides a solid foundation for the large-scale preparation of low-cost and high-performance non-precious metal bifunctional electrocatalysts for the commercial development of electrochemical supercapacitors and electrochemical water-to-hydrogen conversion technology.