One-step synthesis of Zn2GeO4/CNT-O hybrid with superior cycle stability for supercapacitor electrodes

Abstract

Currently, there are three primary obstacles to the development of high-performance supercapacitors: low electron conductivity of the electrode materials used, their poor ion-transport efficiency, and the unstable structure. Herein, to overcome these obstacles, one-dimensional Zn2GeO4 (ZGO) rods were grown within a carbon nanotube (CNT) framework using a simple one-step hydrothermal strategy for use as a supercapacitor electrode material. The crosslinked ZGO/CNT-O hybrid exhibits a large contact surface area with respect to electrolytes, contains abundant electrochemical active sites, and has short ion-diffusion paths. Further, the flexible CNTs act as superior connective bridges, promoting electron transmission and resulting in a stable structure. The ZGO/CNT-O hybrid showed a specific capacitance of 164.25 F/g at a current density of 1 A/g. It also displayed superior cycling durability, exhibiting a specific capacity of 120 F/g at a current density of 10 A/g, even after 200,000 cycles. A simple crosslinking strategy and prolonged cycle durability are demonstrated, which endow ZGO/CNT-O with potential for use in supercapacitor electrodes.