MnO2/polypyrrole-electrodeposited carbonized paper fiber-based for flexible asymmetric supercapacitors with high electrochemical and mechanical reliability

Abstract

The rapid development of intelligent electronic products and wearable devices has stimulated the research upsurge on flexible supercapacitors. However, achieving supercapacitors with both high flexibility and high energy density remains a huge challenge. Herein, we develop a novel strategy to fabricate flexible asymmetric supercapacitor comprised of carbonized paper fiber/graphene/tannic acid (CGTA), manganese dioxide (MnO2) and polypyrrole (PPy) based film electrode. The electrode synthesized via electrochemical deposition avoided the necessity to use non-conductive binders and offered excellent electrochemical performance. The resultant MnO2@CGTA and PPy@CGTA film electrode exhibit high areal specific capacitance of 0.97 F cm−2 and 0.99 F cm−2 at a current density of 1 mA cm−2, respectively. The structural integrity provided by MnO2@CGTA and PPy@CGTA film electrode facilitated excellent electrochemical stability with capacitance retention of 89.93 % and 91.06 % after 5000 charge/discharge cycles, respectively. Furthermore, the flexible asymmetric supercapacitor (MnO2@CGTA//PPy@CGTA) is assembled and it demonstrates high specific capacitance of about 1.383 F cm−2 at 1 mA cm−2, excellent energy density of 192.08 μWh cm−2 at a power density of 0.5 mW cm−2, and good cycle stability of 90.12 % capacitance retention after 10,000 charge/discharge cycles. Even after 500 bending/unbending cycles, still about 86.43 % of its initial capacitance is retained.