MXene/Zn-graphene oxide hydrogels for enhanced energy storage and rate performance in pseudocapacitors

Abstract

The growing demand for high-performance supercapacitors has driven intensive research on two-dimensional (2D) nanoarchitectural materials. This study investigates MXene/Zinc- incorporated graphene oxide (MX:Zn-GO) hybrid hydrogels as pseudocapacitor electrodes to enhance energy storage and rate performance. MXene and Zn-GO were synthesized and assembled into three-dimensional hydrogels at room temperature with different zinc ratios. The morphology and composition were analyzed using scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX), which confirmed distinct layered structures and homogeneous elemental distribution. The electrochemical performance was evaluated using cyclic voltammetry (CV), galvanostatic charge-discharge (GCD), and electrochemical impedance spectroscopy (EIS) in a three-electrode configuration. Among the tested compositions, the MX:Zn-GO (8:2) hydrogel composite, with a Zn:GO ratio of 2:1, exhibited the highest specific capacitance of 360 F g⁻¹, an energy density of 15.1 Whkg⁻¹, a power density of 101 Wkg⁻¹, and 93% capacitance retention after 5000 charge-discharge cycles. These results demonstrate that composition-driven integration of MXene/Zinc-incorporated graphene oxide (MX:Zn-GO) within a hydrogel architecture offers a scalable route toward high-performance supercapacitor electrodes.