Elevating Wearable Tech by Exploring MXene−pBOA−NiO−rGO: A Quaternary Composite for Enhanced Energy Storage in Symmetric Supercapacitors

Flexible supercapacitors show great potential for energy storage, particularly in areas such as flexible electronics, biomedical implants, and self-sustaining energy systems. Their electrodes play a crucial role in enabling these applications. In this study, we have used an aniline-derived polybenzoxazole (pBOA) conducting polymer along with its binary (pBOA-NiO), ternary (pBOA-NiO-rGO), and quaternary (MXene-pBOA-NiO-rGO) configurations deposited over conductive fiber yarn. Electrochemical testing using two electrode configurations revealed outstanding properties of symmetric supercapacitors fabricated from quaternary composite (MXene-pBOA-NiO-rGO) in PMSG gel polymer electrolyte. The MXene-pBOA-NiO-rGO-based supercapacitor with an electrode spacing of 2 mm exhibited specific capacitance and energy density of 338.4 F/g and 16.9 Wh/kg, which outperform several previously reported quaternary composite-based and transition metal oxide-based flexible supercapacitors, thereby demonstrating the superior electrochemical performance of our proposed electrode system. Additionally, this device exhibited a long discharge time of 2000s and a remarkable capacitance retention ratio of 95.5% after 5000 charge–discharge cycles. Such superior electrochemical performance positions these flexible supercapacitors as ideal candidates for energy storage in wearable electronics and self-storage energy systems.