Flexible polypyrrole/cobalt sulfide/bacterial cellulose composite membranes for supercapacitor application

•PPy/CoS/BC composites were prepared by stepwise loading of PPy and CoS on bacterial cellulose (BC) membranes.•Electrochemical performances of composites as supercapacitor electrodes were investigated.•The introduction of CoS remarkably improved the cycling stability of BC-based electrodes.

Bacterial cellulose (BC) has attracted much attention due to its low-cost, high specific surface area and ample porosity. In this work, polypyrrole (PPy) and cobalt sulfide (CoS) have been deposited on BC membranes to prepare the nanofibrous composite electrodes of PPy/CoS/BC with excellent flexibility for supercapacitor application. The introduction of CoS remarkably improves the pseudocapacitance and electrochemical stability of PPy/BC-based electrodes. The specific capacitance of the PPy/CoS/BC-based supercapacitors can reach to about 614 F g−1 at a current density of 0.8 mA cm−2 (0.70 A g−1) with maintaining 62.4% of the original value after 300 cycles; while the PPy/BC-based device could retain only 21.7% after 300 cycles. The PPy/CoS/BC-based devices can exhibit an energy density of about 54.5 Wh kg−1 at a power density of 663 W kg−1. This work provides a promising approach to fabricate cost-effective and flexible membranes which can be used as high-performance supercapacitor electrodes.