Ti3C2Tx/carbon nanotube/porous carbon film for flexible supercapacitor

Abstract

Porous carbon (PC) can effectively alleviate the typical self-stacking phenomenon of 2D MXene-based films as a spacer, and can easily customize their porous structure. Nevertheless, the contact between 3D PC and 2D MXene flakes is generally presented at a point-to-point form owing to the irregular shape of PC, leading to a low efficiency on electron delivery and stress concentration with a fragile characteristic in the resulting films. Herein, 1D carbon nanotube (CNT) was introduced to construct a highly conductive net structure, tightly anchoring PC on MXene flakes, thus ensuring fast electron delivery by increasing the contact area between MXene and PC. Additionally, the interwoven CNTs bridge the horizontal MXene flakes, making internal structure more integral, thereby enhancing the flexibility. Consequently, the Ti3C2Tx (a typical MXene)/CNT/PC (TCP) film has an ability to bear a large scan rate of 1 V s−1 and shows a high areal specific capacitance of 364.8 mF cm−2 at 0.5 mA cm−2 which remains above 80% even at a high current density of 50 mA cm−2. Furthermore, the fabricated flexible quasi-solid-state supercapacitor (SC) demonstrates a large areal energy density of 10.5 μ Wh cm−2 at 29.8 μ W cm−2. This study provides a promising approach to overcome the poor flexibility of MXene/PC film without sacrificing the conductivity, meanwhile paving a way for the development of flexible SCs with large charge storage capacity and high rate capability.