In situ preparation of bacterial cellulose reinforced hydrogel electrolyte for flexible supercapacitors

Abstract

Due to their quasi solid state and high ionic conductivity, hydrogel electrolytes have great potential to be used in flexible supercapacitors (SCs) which is an important group of energy storage systems for portable devices. However, most hydrogels perform low mechanical properties and bad contact to flexible electrodes, especially under various deformations. Herein, we have prepared one hydrogel electrolyte with a double network created by poly acrylic acid (PAA) and sodium alginate (SA). PAA was chemically crosslinked by poly(ethylene glycol) diacrylate (PEGDA), where SA was ionic crosslinked by Ca2+. This hydrogel is also reinforced by bacterial cellulose (BC) clusters. In-situ polymerization was conducted to directly prepare this hydrogel electrolyte in the presence of two graphene based flexible electrodes. The resultant hydrogel was characterized by ATR-FTIR and scanning electron microscopy (SEM). Its shrinkage, mechanical property and ionic conductivity in KCl were also investigated. The electrochemical performance of assembled SC was subsequently studied. The results show our prepared hydrogel electrolyte has a promising application in flexible SCs.