MOFs-derived 3D porous ZnCo2O4 nanocubes intercalated 3D graphene electrode for superior lifespan hybrid supercapacitors

Abstract

Despite the escalating energy crisis and mounting environmental concerns, it is evident that conventional energy storage can no longer fulfil the demands of modern society. Consequently, supercapacitors have gained significant popularity as energy storage devices owing to their outstanding efficiency. Nevertheless, the limited energy density of this substance restricts its potential applications. Herein, the robust and controllable design of ultra-porous zinc cobaltite nanocubes (ZnCo2O4 Nc) is successfully fabricated using a MOF-templated approach. The ZnCo2O4 Nc is interconnected with 3D graphene nanosheets (ZnCo2O4 Nc@3DGr) as electrodes for hybrid storage devices. However, the (ZnCo2O4 Nc@3DGr) nanocomposite electrode exhibits better specific capacity/capacitance of (824.4 C/g, 1374 F/g) at a current density of 1 A/g compared to pristine ZnCo2O4 Nc (567 C/g, 945 F/g). For Full cell device configuration, the designed hybrid supercapacitor (HSC) is constructed using ZnCo2O4 Nc@3DGr (positive) and 3DGr (negative) electrodes. The constructed ZnCo2O4 Nc@3DGr//3DGr hybrid device delivers a maximum energy density of 60 Wh/kg with a power density of 800 W/kg and an ultralong lifetime with a minimum ~7% capacitance loss up to 11,000 cycles.