MXene nanomesh for high-performance supercapacitor.

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 Ti 3 C 2 nanomesh via the chemical oxidation-etching process. The rich in-plane pores in Ti 3 C 2 nanomesh provide abundant pathways and new active sites for ion transfer/adsorption, greatly improving the electrochemical activity. Specifically, the obtained Ti 3 C 2 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 Ti 3 C 2 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 Ti 3 C 2 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. • Ti 3 C 2 MXene nanomesh was constructed by chemical oxidation and etching. • The restacking issue was solved by the rich in-plane pores in MXene nanomesh. • Our design provides a promising way for high performance supercapacitors. [ABSTRACT FROM AUTHOR]