Multiple phase transformation of ZIF-L to LDH and Ag nanoparticles decorated on CoNi layered double hydroxides for high-performance supercapacitor and highly efficient hydrogen evolution reaction

ZIF-L-derived binary layered double hydroxide (LDH) established active catalysts have been shown to have potential as electrode materials in the development of high-performance supercapacitors (SCs) and hydrogen evaluation reactions (HER). This study uses conductive nano-silver (Ag) particles in hierarchically integrated CoNi-LDH nanosheets (NSs), which are described. The developed Ag@CoNi-LDH NSs electrode has a very high specific capacitance of 2878 F g⁻¹ at 0.5 A g⁻¹ and an impressive rate capability. This is due to consistent morphology, plentiful electroactive sites, homogeneous particle size, and decreased electronic/ionic impedance. The fabrication of solid-state hybrid supercapacitors (HSCs) using Ag@CoNi-LDH NSs as the positive electrode and activated carbon (AC) as the negative electrode in PVA/KOH polymer gel electrolytes has been described. The prepared supercapacitors achieve a maximum energy density of 105 Wh kg⁻¹ at power densities of 1183 Wh kg⁻¹, coupled with excellent initial capacitance retentions of 97 % after 20,000 cycles. Ag@CoNi-LDH NSs demonstrate effective electrocatalytic activity towards HER with an ultra-low overpotential of 26 mV at 10 mA cm⁻² and the associated Tafel value of 35 mV dec⁻¹ using 0.5 M acidic electrolyte. It is possible to attribute the extraordinary electrochemical performance to the thoughtful mixture of two electroactive materials in the future.