Construction of Ti3C2Tx/WOx heterostructures on carbon cloth for ultrahigh-mass loading flexible supercapacitor

The capacitance loss caused by slow electron and ion migration kinetics in thick electrode with high-mass loading has been regarded as a great challenge in the field of electrochemical energy storage. Herein, we demonstrate a facile electrochemical deposition method for coating the heterostructured Ti3C2Tx/WOx onto flexible carbon cloth (Ti3C2Tx/WOx@CC). In the Ti3C2Tx/WOx heterojunction, the mixed-valence WOx core provides abundant active sites for H+ ions accommodation, while Ti3C2Tx shell can not only prevent peeling off the thick WOx but also act as an interconnected conductive network. The Ti3C2Tx/WOx@CC flexible electrode with an ultrahigh mass loading of 34.9 mg·cm−2 exhibits a high areal capacitance of 5.73 F·cm−2 at 5 mA·cm−2 and excellent rate capability. Notably, the Ti3C2Tx/WOx@CC electrode under such a high mass loading still delivers a gravimetric capacitance of 164 F·g−1 and areal capacitance of Ti3C2Tx/WOx@CC electrode increases linearly with the WOx mass loading. Furthermore, a symmetrical supercapacitor assembled with Ti3C2Tx/WOx@CC electrode exhibits a good areal energy density of 96.8 μWh·cm−2 at a power density of 1.5 mW·cm−2. This work verifies high mass loading of active materials per unit electrode area for charge storage of supercapacitors in limited space, indicating the great potential in the development of commercially available thick metal-oxide film supercapacitors.