Vertically aligned graphene-MXene nanosheets based electrodes for high electrochemical performance asymmetric supercapacitor

Abstract

Vertically aligned porous morphologies have attracted much attention due to their long-range ordered channel structures. Here, a novel 3D vertically aligned graphene-MXene nanosheets based electrochemical supercapacitor is designed. Graphene oxide and Ti3C2TX MXene are used to prepare a vertically aligned porous bridge substrate (the pore size of 7 μm) by an ice template directional solidification method. Polyaniline nanowire arrays (PANI NWAs) are in-situ grown on the substrate by a polymerization process (positive electrode) and the substrate with more MXene is used as the negative electrode. After assembling into an asymmetric supercapacitor (ASC), the vertically aligned porous morphology is conducive to accelerating the directional transport of ions, which obviously improves the electrochemical properties of the ASC. The calculated specific capacitance of the ASC is 108F/g (at 1 A/g). The energy density of the ASC can reach 38 Wh/kg (at the power density of 810 W/kg) and the cycle stability is 82 % after 10, 000 cycles at 10 A/g.