Facile synthesis of ZnWO₄nanowall arrays on Ni foam for high performance supercapacitors

Abstract

In this report, ZnWO4 nanowall arrays (NWAs) were grown on Ni foam by a hydrothermal route and investigated for application in supercapacitors for the first time. The resulting NWAs were analyzed by using X-ray diffraction spectroscopy, scanning electron microscopy, and transmission electron microscopy. ZnWO4 NWAs exhibited high electrochemical property with a specific capacitance of 2.5 F cm−2 at a charge and discharge current density of 20 mA cm−2 (1250 F g−1 at current density of 10 A g−1). Furthermore, they showed an excellent cycling ability at different current densities up to 100 mA cm−2, and 92% (2.3 F cm−2) of the initial capacitance remained after 4000 cycles. The open network structure consisting of interconnected ZnWO4 NWAs directly grown on current collectors is advantageous for electron transport and electrolyte diffusion which can facilitate the electrochemical reaction. Our work not only demonstrated a facile hydrothermal method for ZnWO4 NWAs directly grown on Ni foam, but also revealed ZnWO4 to be a promising electrode for high-property supercapacitors.