Gadolinium doped zinc ferrite nanoarchitecture reinforced with a carbonaceous matrix: a novel hybrid material for next-generation flexible capacitors

Abstract

Herein, nanostructured Gd-doped ZnFe₂O₄ (GZFO) has been synthesized via the sol–gel route and its CNT-reinforced nanohybrid was formed via an advanced ultrasonication method. The as-synthesized, hybrid electroactive materials have been supported on aluminum foil (AF) to design a flexible electrode for hybrid capacitor (HC) applications. Nanostructured material synthesis, Gd-doping, and CNT reinforcement approaches have been adopted to develop a rationally designed electrode with a high surface area, boosted electrical conductivity, and enhanced specific capacitance. Electrochemical impedance spectroscopy, galvanostatic charge/discharge, and cyclic voltammetry processes have been used to measure the electrochemical performance of the prepared ferrite material-based working electrodes in a 3M KOH solution. A nanohybrid-based working electrode (GZFO/C@AF) shows superior rate capacitive and electrochemical aptitude (specific capacitance, rate performance, and cyclic activity) than its counterpart working electrodes (ZFO@AF and GZFO@AF). The hybrid working electrode (GZFO/C@AF electrode) shows a high specific capacitance of 887 F g⁻¹ and good retention of 94.5% for 7000 cycles (at 15 Ag⁻¹). The maximum energy density and power density values for the GZFO/C@AF electrode are 40.025 Wh Kg⁻¹ and 279.78 W Kg⁻¹, respectively. Based on the findings of the electrochemical experiments, GZFO/C@AF shows promise as an electrode material for hybrid capacitors that provide energy to wearable electronic devices.