MXene nanomesh for high-performance supercapacitor

Abstract

The merits of excellent electrical conductivity, good hydrophilicity, and large specific capacitances render MXene film electrodes attractive in supercapacitors (SCs). However, the tortuous ion transfer in restacked nanosheets limits the electrochemical performance of dense film electrodes. To solve the ion transfer issue, we propose a strategy to produce porous films assembled by Ti3C2 nanomesh via the chemical oxidation-etching process. The rich in-plane pores in Ti3C2 nanomesh provide abundant pathways and new active sites for ion transfer/adsorption, greatly improving the electrochemical activity. Specifically, the obtained Ti3C2 nanomesh films exhibit high specific capacitances of 235 F g-1 at 1 A g-1 and 184 F g-1 at 10 A g-1 in 6 M KOH, which are ∼2 times higher than the pristine Ti3C2 films (118 F g-1 at 1 A g-1 and 90 F g-1 at 10 A g-1). Furthermore, hybrid capacitors, composed of the Ti3C2 nanomesh films as the negative electrodes and Ni-Co layered double hydroxides as the positive electrodes, in KOH electrolytes, are also demonstrated to show practicability. This work provides an opportunity to develop high-performance energy storage devices with the 2D nanomesh.