Synthesis and Enhancement of Electroactive Biomass/Polypyrrole Hydrogels for High Performance Flexible All-Solid-State Supercapacitors

Recently, electroactive biomass-based hydrogels have attracted great attention for flexible supercapacitor electrodes due to its porous, renewable, earth-abundant, low-cost, and environmentally friendly characters. However, it is challenging to facilely prepare biomass-based hydrogels with simultaneously possesses high mechanical strength and excellent electrochemical performance. In this work, the lignosulfonate/polypyrrole (Lig/PPy) hydrogel (LP54) is obtained. In order to further improve the mechanical strength and electrochemical performance of LP54, functionalized porous carbon nanospheres/lignosulfonate/polypyrrole hydrogel (FPCSLP54) is prepared by introducing a trace of FPCS (approximate to 4.5 wt%) fabricated by hydrothermal treatment the mixture of PCS and pyrrole into the prepared LP54 system. FPCS can be uniformly anchored into Lig/PPy framework. The LP54 and FPCSLP54 exhibit compressive strength of 6.0 and 9.3 kPa with the water content of 94.9% and 94.3%, respectively. Meanwhile, as-prepared LP54 and FPCSLP54 are separately assembled into symmetric flexible supercapacitors with cellulose/H2SO4 hydrogel electrolytes, which exhibit superior areal capacitance (463 and 522 mF cm(-2)), good rate capability and outstanding energy density (41.2 and 72.5 mu Wh cm(-2)). Remarkably, flexible supercapacitors present outstanding electrochemical stability even suffering 1000 bending cycles. In this work, the strategy to construct electroactive biomass-based hydrogels is contributed and a new method to enhance the properties of hydrogels is provided.