A multifunctional hydrogel polyelectrolyte based flexible and wearable supercapacitor

Abstract To well satisfy the newly emerging personalized electronics, it is urgent to develop durable and reliable flexible energy storage devices having a favorable match with them. However, conventional polymer matrixs based hydrogel electrolytes inevitably limit the development of desired supercapacitors due to their poor stretchable, healable as well as electrochemical properties. Here, a novel multifunctional hydrogel polyelectrolyte (VHSNPs-PAA/H2SO4/ARS) is developed comprising the alizarin red S (ARS) redox mediator and the double cross-linked polyacrylic acid (PAA) by the vinyl hybrid silica nanoparticles (VHSNPs) and hydrogen bonds, which realized the combination of ultrahigh stretchability (~2400% strain), robust mechanical toughness (lift up the 500 g weights), favorable self-healability (~92% efficiency during 10 cutting/healing cycles), high ionic conductivity (33 mS cm−1), powerful self-adhesiveness and superior redox activity within a single hydrogel structure. The facilely fabricated carbon-based supercapacitor using the obtained hrdrogel as the electrolyte can achieve large electrode specific capacitance of 248 F g−1 and high mass energy density of 16.7 W h kg−1, which are much larger than the recently reported stretchable and self-healing hydrogel electrolytes based flexible supercapacitors. Meanwhile, as-fabricated device also exhibits the excellent cycling stability and superior durability against physical deformation after 5000 charge-discharge cycles and 200 bending-releasing cycles, respectively.