High-Strength Self-Healable Supercapacitor Based on Supramolecular Polymer Hydrogel with Upper Critical Solubility Temperature

Here, poly(N-acryloylglycinamide-co-vinyltriazole) p(NAGA-co-VTZ) supramolecular polymer hydrogel doped with carbonized and activated polypyrrole nanotubes as a high-strength self-healable material is presented for supercapacitors. Initially, the p(NAGA-co-VTZ) hydrogel films are synthesized by photopolymerization of N-acryloylglycinamide and 1-vinyl-1,2,4-triazole without the use of any cross-linkers. The hydrogels demonstrated remarkable self-healing ability via hydrogen bonding at temperatures above upper critical solubility temperature, excellent mechanical properties (0.86 MPa), large stretchability (1300%) and cut resistance. Subsequently, carbonized and ethanol/KOH-activated polypyrrole nanotubes (acNTs) are prepared as the active material for electrochemical double-layer capacitors (EDLC). Then, a symmetric self-healable supercapacitor employing p(NAGA-co-VTZ) hydrogel, acNTs and aqueous 3 m KCl solution is assembled. Cyclic voltammetry and galvanostatic charge-discharge measurements show that the prepared device gives a specific capacitance of 282.62 F g-1 at 0.2 A g-1 and a high areal capacitance of 316.86 mF cm-2 at a scan rate of 10 mV s-1. Importantly, the supercapacitor operates over a wide voltage window (0-1.2 V) and provides excellent cyclic performance with capacitance retention of 97% after 10 000 cycles and 94% after self-healing. In summary, the developed self-healable supercapacitor exhibits considerable potential as a high-performance energy storage device. Supramolecular poly(N-acryloylglycinamide-co-vinyltriazole) (p(NAGA-co-VTZ) polymer hydrogel doped with carbonized and KOH-activated polypyrrole nanotubes, serving as a high-strength, self-healable material for supercapacitors. This hydrogel exhibits remarkable fast self-healing ability through hydrogen bonding at temperatures above the upper critical solubility temperature, along with excellent mechanical properties. The influence of the copolymer composition on important properties is described. image