Facile preparation of Ga-doped ZnO nanostructures by composite-hydroxide-mediated synthesis route for high-performance pseudocapacitors

Supercapacitors are widely recognized to be a significant class of energy storage technologies serving a range of uses. However, it is still urgently necessary to develop the same employing resources that are abundant on earth and are eco-friendly while maintaining excellent performance. Herein, Ga-doped ZnO nanostructures of different Ga concentrations were prepared by a composite-hydroxide-mediated (CHM) approach. The XRD, Raman, FT-IR, and EDX results confirmed the doping of Ga into ZnO. The dielectric properties of pure ZnO and Ga-doped ZnO have been examined at room temperature, revealing that the dielectric constant and the ac conductivity increased by Ga doping, while the dielectric loss reduced. The obtained results showed that 0.8 % Ga-ZnO electrode possesses a maximum value of the specific capacitance (Cp) 440.9 F/g at 1 mV s-1 and 482.5 F/g at 1 A/g with noticeably specific energy (10.8 Wh/kg) and high specific power (200 W/kg). A high capacitance retention capability (80 %) was also maintained by 0.8 % Ga-ZnO electrode after 3000 cycles. The prepared electrode materials are a better choice for high-performance supercapacitors in order to meet the ongoing need for energy storage devices.