One-step sonochemical synthesis of NiMn-LDH for supercapacitors and overall water splitting

Transition metals are attracting numerous interests for their substantial applications in supercapacitors and as non-noble metal electrocatalyst for overall water splitting. Herein, the NiMn layer double hydroxide (NiMn-LDH) is developed using the sonochemical route at different reaction times, which act as a multifunctional electrode for supercapacitors and overall water splitting. The capacitance of layer double hydroxide (LDH) synthesized at 4 h (NiMn-LDH-4 h) of reaction time was found to be 527 F g⁻¹ at 1 A g⁻¹, with 91.2% capacitance retention after 5,000 cycles at 2 A g⁻¹ in 6 M KOH. For hydrogen and oxygen evolution reactions, the NiMn-LDH-4 h electrode exhibits a standard of 10 mA cm⁻² at an overpotential of 120 mV and 296 mV, respectively, in 1 M KOH. Moreover, fabricated NiMn-LDH-4 h||NiMn-LDH-4 h electrolyzer for overall water splitting benchmarks 10 mA cm⁻² at 1.6 V. The superior electrochemical properties of the NiMn-LDH electrodes might be attributed to quick diffusion paths and enhanced redox reaction of NiMn-LDH nanosheets because of the high surface area.