Electrochemical performance of rGO@ZnCo2O4 microspheres: rationally designed asymmetric constructed wide-potential energy storage device

Abstract

In the present work, we have synthesized reduced graphene oxide supported ZnCo2O4 microspheres (MSs) using a simple hydrothermal process. The porous shield consistency of rGO@ZnCo2O4 microspheres (MSs) brings a three-time increase in specific surface area (67 m2g?1) for a high-performance electrode. The rGO@ZnCo2O4 MSs electrode facilitates a high specific capacity of 123 mAhg?1 at 4 Ag?1 along with excellent capacity retention of 95% up to 2500 cycles. The performance of rGO@ZnCo2O4 MSs is credited to the synergic effects of rGO and ZnCo2O4, and highly porous morphology. Further, rGO@ZnCo2O4//Activated Carbon based solid-state asymmetric device is designed with polymeric gel electrolyte, which attains a wide potential window of 1.8 V with a specific capacity of 109 mAhg?1. The device exhibits a power density of 1163 kWkg?1, and an energy density of 42 Whkg?1. This is attributed to enhanced redox reactions, increased availability of electrochemical active sites, and a minimal charge transfer resistance provided by porous microspheres (MSs) during electrochemical reactions. A practical demonstration displays lightning of an array of blue LEDs. The attractive electrochemical performance of rGO@ZnCo2O4 MSs proposes a new morphological improvement for next-generation energy storage devices.