Self-healable PVA-Borax-K₂SO₄ hydrogel electrolyte for flexible symmetric supercapacitors

The self-healing hydrogel materials are formed from the reaction between polyvinyl alcohol (PVA) and sodium tetraborate (Borax). The O-B-C vibration peak from the FT-IR spectrum is used to confirm the formation of the self-healing hydrogel structure. With 0.5 M concentration K 2 SO 4 , the resistivity of PVA-Borax-K 2 SO 4 material is evaluated by Bode cure and obtained at 4.13 Ω.cm. With the improvement in hybrid structure, the flexible supercapacitor (FSS) devices were fabricated from two carbon fiber fabrics as symmetric electrodes with a self-healing hydrogel material (PVA-Borax-K 2 SO 4 ) as electrolyte and separator. The electrochemical performances of flexible symmetric supercapacitor (FSS) devices are measured by cyclic voltammetric, charge/discharge, and impedance tests. The specific capacitance of FSS obtained 1.725 mF/cm 2 at 0.05 mA/cm 2 discharge current. Moreover, the stability of the FSS device attained confirmation by the comparison of the specific capacitance at 2 and 50 cycles.