Unleashing the Potential of Binder-Free Hydrothermally Synthesized Marigold-Like ZnCo2O4 for Supercapacitors

Abstract

An enormous interest has been generated in hybrid structured capacitive materials for supercapacitor. However, the sensible design with modified electro-mechanism and high energy density is still a demanding for supercapacitors. In this report, we developed a binder-free marigold ZnCo2O4 architectures on conducting Ni foam substrate from a simple one pot hydrothermal assisted thermal annealing process and used as an electrode for supercapacitor application. The electrode demonstrates a high specific capacitance of 1167 F g−1 (227 mAh g−1) at 1 mA cm−2 in 1 M KOH electrolyte. In addition, hybrid supercapacitor device was also fabricated by assembling as prepared marigold flowers-like ZnCo2O4 as positive electrode and activated carbon (AC) as the negative electrode, providing superior specific capacitance (166.7 F g−1 or 94.4 mAh g−1 at 1 mA cm−2) and long cycling stability (81.38 % after 10,000 cycles at 30 mA cm−2), the maximum energy and power density of 306 Wh kg−1 and 10,800 W kg−1 respectively, also a low resistance (0.9 Ω) value. Our work justify that the ZnCo2O4 marigold flowers-like electrode will be suitable for both criteria like high energy and power density appliances such as electric vehicles, portable electronics, and power storage systems.