A self-healing and deformation responsive supercapacitor fabricated using a smart gel polymer electrolyte and a redox-activated electrode

Abstract

A flexible, intelligent supercapacitor is designed and fabricated using a smart gel polymer electrolyte (GPE) and redox-activated electrodes. This flexible, intelligent supercapacitor exhibits superior electrochemical, self-healing, and deformation-responsive properties. Methylene blue (MB) and Na₂MoO₄ are added to the self-healing gel of PVA–H₃BO₃–H₂SO₄ (PS) to generate smart GPE PVA–H₃BO₃–H₂SO₄–MB–Na₂MoO₄ (PSMMo) with temperature and deformation sensitivity. The response current of smart GPE PSMMo exhibits a positive correlation with the working temperature. The bending process induces peak current generation, whose variation in magnitude depends on the bending degree. Na₂MoO₄, MB, and polyaniline (PANI) are used to modify activated carbon paper (ACP) to form Na₂MoO₄–ACP and MB–PANI–ACP redox-activated electrodes, which are combined with smart GPE PSMMo to form an intelligent supercapacitor. The matching faradaic reaction of Na₂MoO₄–ACP, MB–PANI–ACP electrodes and PSMMo electrolyte provides the interfacial redox reactivity to contribute to superior pseudocapacitance. The Na₂MoO₄–ACP supercapacitor (83.93 mF cm⁻²) and MB–PANI–ACP supercapacitor (250.23 mF cm⁻²) have obviously much higher specific capacitance than the ACP supercapacitor (53.42 mF cm⁻²) and PANI–ACP supercapacitor (141.78 mF cm⁻²). The MB–PANI–ACP supercapacitor has an energy density of 681.18 mW h m⁻² at 0.5 mA cm⁻². Theoretical simulation calculations verify the contribution of redox-activated electrodes to electrochemical performance. The smart GPE PSMMo-based supercapacitor exhibits self-healing, deformation response and faradaic capacitance contribution properties which are far superior to those of a normal GPE-based supercapacitor with self-healing properties.