A Novel Strategy to Enhance the Electrochemical Performance of Polypyrrole‐Coated Paper‐Based Supercapacitor

AbstractA novel strategy is proposed to enhance the electrochemical performance of polypyrrole (PPy)‐coated cellulose paper (PCP)‐based supercapacitor by increasing the reaction interface between hydrophobic pyrrole and hydrophilic FeCl3 solution. Paper is pretreated with regenerated cellulose (RC) to increase its specific surface area, which lays the foundation for increasing the reaction interface between pyrrole and FeCl3 in the following in situ polymerization while providing more adsorption sites for PPy. The RC‐pretreated paper is first impregnated with pyrrole, followed by removing surplus pyrrole occupied by the internal pores of paper prior to the impregnation of FeCl3 solution, aiming to increase the reaction interface between pyrrole and FeCl3 solution. Consequently, the as‐prepared PCP electrode exhibits a PPy loading of 4.2 mg cm−2, which is twofold higher than unpretreated PCP electrodes (2 mg cm−2). Moreover, a solid‐state supercapacitor assembled with PCP electrodes presents a 58 mF cm−2 areal capacitance at 2 mA cm−2 (equivalent to 140.5 F g−1 at 0.5 A g−1), a 33.1 µWh cm−2 energy density at a power density of 0.60 mW cm−2, and excellent cycling stability with a capacitance retention of 91.6% after 10 000 CV cycles. This work offers a new insight toward improving the electrochemical performance of PCP‐based supercapacitor.