Integrated polyphase hydrogel and preparation method and application thereof in flexible and stretchable supercapacitor

A method for preparing a flexible and stretchable supercapacitor by using an integrated polyphase hydrogel, comprising:

• preparing the integrated polyphase hydrogel through steps of:
• (1) dissolving polyvinyl alcohol and phytic acid in water, then adding sulfuric acid, stirring at 75-95° C. for 2-3 h to obtain a homogeneous solution, and then cooling to room temperature to form PVA/SA/PA semigel electrolyte, wherein the PVA/SA/PA semigel electrolyte is composed of the following mass fractions of raw materials:
• 13.76-26.20% of polyvinyl alcohol, 58.07-80.64% of phytic acid, and the balance of sulfuric acid,
• (2) dissolving the polyvinyl alcohol in the phytic acid, stirring at 75-95° C. for 2-3 h, then adding ammonium persulfate and heteropoly acid to obtain a homogeneous solution, adding phytic acid and aniline to the solution, stirring continuously at 75-95° C. for 3-4 h, and freezing at −30 to −20° C. for 4-6 h to obtain a PVA/PA/PANI/HPA semigel electrode, wherein the heteropoly acid is H3PW12O40 and H3PMo12O40;
• and the PVA/PA/PANI/HPA semigel electrode is composed of the following mass fractions of raw materials:
• 7.97-10.4% of polyvinyl alcohol, 53.14-69.84% of phytic acid, 9.52-29.63% of heteropoly acid, 1.72%-2.44% of aniline and the rest of ammonium persulfate,
• (3) injecting the PVA/SA/PA semigel electrolyte into a mold, and then injecting the PVA/PA/PANI/HPA semigel electrode into the PVA/SA/PA semigel electrolyte to form parallel electrodes with controllable spacing;
• covering the mold with the PVA/SA/PA semigel electrolyte to ensure that the PVA/PA/PANI/HPA is fully embedded into the bulk phase of the PVA/SA/PA semigel electrolyte, finally freezing the mold and then thawing at room temperature to obtain an integrated polyphase hydrogel;
• and
• using the integrated polyphase hydrogel to ensure that two parallel gel electrodes are completely placed in a gel electrolyte in a preparation process of the flexible and stretchable supercapacitor to form an integrated polyphase gel comprising both the electrodes and the electrolyte;
• and
• then connecting a carbon cloth at one end of each electrode respectively to obtain the flexible and stretchable supercapacitor.