Flexible self-support carbon-based material with N[sbnd]F doping and Co embedding for supercapacitors

Abstract

A flexible porous self-support activated carbon electrode material with NF doping and Co embedding is obtained (ACC@PVDF0.1) by a simple pyrolysis method at a relatively low temperature (600 °C). The multifunctional interface is prepared from polyvinylidene fluoride (PVDF) powder as the carbon and fluorine sources, ZIF-67 as the nitrogen source. After a simple physical covering on an activated carbon cloth (CC), pyrolysis under nitrogen gas environment, the porous self-support activated carbon electrode material with N, F doping and Co embedding can be obtained. The obtained carbon-based material has merits of high specific area (399.8 m2 g−1), high wettability and conductivity because of the N and F doping. The prepared carbon material displays a specific areal capacitance of 0.717 F cm−2 at the current density of 1 mA cm−2 in 1 M Na2SO4, and the capacitance retention remains 92.7 % after 10,000 charge-discharge cycles. An asymmetric supercapacitor (ASC) based on the substrate material of ACC@PVDF0.1 is assembled with the MnO2/AC@PVDF as the positive electrode and the Mxene/AC@PVDF as the negative electrode. It can be operated in a 0–1.8 V voltage window, and demonstrates a specific capacitance of 0.415 F cm−2 in 1 M Na2SO4 at the current density of 1 mA cm−2. The power density is 11.24 mW cm−3 at the energy density of 2.33 mWh cm−3, which shows that the prepared activated carbon material may be a promising candidate for flexible self-support supercapacitors in future.