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.

This paper explores different techniques to combine and improve the electrochemical sensing activities of the transition metal chalcogenide. The transition metal chalcogenide was doped with a suitable dopant to tune the band structure. Surface-assisted nanotechnology was used to enrich the superficial properties of the doped material. Lastly, the nanostructured doped materials were physically mixed with the graphene nanoplates (GNPs) to improve the flow of charges and the stability of the electrochemistry. The most electrically conductive and common metal sulfides in nature were chosen and prepared using a cheap and easy wet-route method. Crystal structure, chemical functionality, texture, composition, and thermal stability of undoped, doped, and composite materials were determined using physicochemical techniques such as X-ray diffraction, FTIR, SEM, EDX, and TGA. N₂-adsorption-desorption, current-voltage, and impedance studies show that the composite sample’s surface area, electrical conductivity, and charge transport properties are superior to those of the undoped and doped samples. Regarding electrochemical applications, the composite material supported a glassy carbon electrode (Co–Cu₂S/Gr@GCE) with excellent Pb(II) ion sensing activity. Moreover, the sensitivity, detection, and quantification limits of the modified electrode for Pb(II) detection were computed to be 88.68 μAμMcm⁻², 0.091 μM, and 0.30 μM, respectively. The key features developed in the metal sulfide for its enhancement of electrochemical sensing activity are a high surface area, good conductivity, and fast electron transport by adopting nanotechnology, metal doping, and composite formation methodologies. Based on the results of the experiments, we can say that using multiple inputs to integrate the feature we want is an excellent way to make electrochemical systems for the next generation.