Enhanced pseudocapacitor performance using polyaniline‑zirconium dioxide nanocomposite all-in-one hydrogel

Abstract

Hydrogel electrolytes play a distinct and vital role in the development of flexible supercapacitors, as they facilitate excellent interfacial contact with the electrodes. Nevertheless, there remains a substantial opportunity for further development in supercapacitor design, particularly when employing binder-type electrode materials. This is due to the presence of interfacial contact resistance, which can compromise the supercapacitor's performance. Additionally, there are instances where the electrode materials fail to adhere completely to the electrode substrate, leading to a decline in the electrochemical performance of the supercapacitor. To address these challenges, a self-healing, all-in-one hydrogel supercapacitor was fabricated via in-situ polymerization of aniline and Zirconium dioxide (ZrO₂) nanocomposites on the surface of self-healing natural rubber-based hydrogel electrolyte. This study introduces ZrO₂ nanoparticles along with polyaniline to enhance the all-in-one supercapacitor's performance, leveraging their exceptional structural, thermal, and electrochemical properties. When subjected to galvanostatic charge-discharge tests, the flexible all-in-one hydrogel supercapacitor displayed impressive areal capacitances, reaching 36.59 mF/cm², 42.59 mF/cm², and 47.62 mF/cm² for PZ0, PZ1, and PZ3 respectively, at a current density of 0.5 mA/cm². Notably, the highest energy density and power density were achieved by PZ3 (containing 0.3 wt% ZrO₂), yielding 144.67 μWh/cm² (at 0.5 mA/cm²) and 1345.10 μW/cm² (at 1 mA/cm²), respectively. Even at higher current densities (1 mA/cm²), the all-in-one hydrogel supercapacitor retained 61.84 % of its initial capacitance. These remarkable electrochemical properties of PZ3 are attributed to the ZrO₂ incorporation, by promoting Faradaic reactions at the electrode.