ZnCo-layered double hydroxides coupled polyaniline-derived porous carbon: An efficient electro-catalyst towards supercapacitor and fuel cells application

In this work, layered double hydroxides (LDH) with Zn and Co are synthesized and coupled with polyaniline-derived porous carbon (PC). Synthesized electro-catalysts are characterized by various characteristics such as structure, chemical, thermal, surface, electronic structure, and morphology analysis. ZnCo-LDH/PC electro-catalyst delivered the highest specific capacitance (Csp) of 3222.5 at 1 A/g with satisfactory Csp rate retention of 64.2 %. The solid-state SCs are fabricated with ZnCo-LDH/PC and activated carbon as positive and negative electrodes. The fabricated solid-state supercapacitor exhibited an energy density of 30.13 Wh/kg at a power density of 1.6 kW/kg and operated stably up to 3000 cycles with a stability loss of 2.7 %. In the second application, the same electro-catalyst was applied to the fuel cell cathode for ethanol oxidation reaction (EOR) and oxygen reduction reaction (ORR) as the prime reaction. In EOR, synthesized ZnCo-LDH/PC exhibited the highest mass activity and electrochemical active sites of 71 mA/mg and 180 cm2, respectively, with a lower slope of 20 mV/dec. And in the ORR kinetics study for ZnCo-LDH/PC, a four-electron transfer process is achieved, and ethanol tolerance is compared to standard platinum/carbon. Also, ZnCo-LDH/PC electro-catalysts delivered relative current stability of 89 % for 10,000 s. Therefore, ZnCo-LDH/PC, with its novelty in supercapacitor positive side and fuel cell cathode electro-catalyst, gives an edge towards energy storage and conversion. Hence, this study could bring the practical ability combination for energy conversion and storage that could owe the necessary future infrastructural for the growth of society.