Hollow polypyrrole/cellulose hydrogels for high-performance flexible supercapacitors

A lightweight, flexible, and highly efficient energy management strategy is a requisite for future flexible electronics. Herein, hollow polypyrrole/cellulose hybrid hydrogels featured with biphase porous structures, are firstly designed by in-situ implanting a hollow and continuous polypyrrole conducting network into porous cellulose hydrogels. Such hollow hybrid hydrogels show good mechanical strength and flexibility, enabling its ability to bear severe mechanical deformation without structural damage. Within the hybrid hydrogel, cellulose hydrogel acts as an interior electrolyte reservoir to host movable ions, biphase porous structure offers path for electrolyte ions transportation, and hollow polypyrrole network is responsible for the electrochemical contribution. As a result, a symmetrical supercapacitor assembled with the hollow hybrid hydrogels delivers optimized capacitive properties with a high specific capacitance, a good rate capability, and an enhanced cycling stability. Moreover, no evident loss in capacitance of the device is observed even bended at 180 degrees. This work provides a design of flexible, low-cost, environmental-friendly and high-performance electrode materials for energy conversion and storage systems.