Vertical porous Ti3CNTx/rGO hybrid aerogels with enhanced capacitive performance

Abstract

Two-dimensional MXenes have shown great application potential in high-performance supercapacitors due to their high conductivity and excellent intercalation pseudocapacitance. Thereinto, compared with previously reported Ti3C2Tx, Ti3CNTx MXene with unique C and N atom-layer structure was predicted to achieve higher capacitive performance. However, the nanosheet restacking and complex ion-diffusion paths often limit the capacitance and rate performance of MXene-based electrodes. At this point, we proposed to construct vertical porous Ti3CNTx/rGO hybrid aerogel electrodes through a unidirectional bottom-up freezing process. The vertical porous structure would greatly shorten the ion diffusion paths. Furthermore, the introduced rGO nanosheets would impede the restacking of Ti3CNTx nanosheets, improving the accessibility of electrolyte ions. As a result, the Ti3CNTx/rGO hybrid aerogels delivered significantly improved gravimetric capacitance of 390 F g−1, high-rate performance (205 F g−1 at 1000 mV s−1) and great cycling stability (98 % capacitance retention after 10,000 cycles). This work not only proved the great superiority of vertical porous Ti3CNTx/rGO hybrid aerogels but also opened a new door for Ti3CNTx and other MXenes to be used for high-performance supercapacitors.