In Situ Grown MWCNTs/MXenes Nanocomposites on Carbon Cloth for High‐Performance Flexible Supercapacitors

Owing to their large surface‐area‐to‐volume ratios, 2D titanium carbides and nitrides (MXenes) have emerged as promising materials for energy storage devices. However, poor interlayer and interparticle conductivity of MXenes (due to its anisotropic nature) is a bottleneck for widening their applications. Additionally, the stacked structure of MXene sheets limits the exposed surface area and renders a complex electrolyte diffusion. To address these issues, a unique composite comprising of homogeneously grown multiwall carbon nanotubes (MWCNTs) on carbon cloth (CC)‐supported MXene sheets (denoted as MWCNTs‐MXene@CC) is proposed. The MWCNTs‐MXene@CC reveal the synergistic combination of exfoliated large surface area and excellent conductivity. Consequently, the fabricated electrode exhibits a specific capacitance of 114.58 mF cm−2 at a discharge current of 1 mA cm−2, while maintaining high retention after 1.6 × 104 cycles at 10 mA cm−2. Such high performance of the composite structure is attributed to the superb interlayer and interparticle conductivity imparted by the grown MWCNTs. Furthermore, the grown MWCNTs also serve as the interlayer pillar in MXene sheets, thus preventing the spontaneous collapse of the latter. The approach can be extended to other electrocatalyst systems in which ion transport and electrolyte diffusion need to be addressed simultaneously. An MWCNT‐MXene nanocomposite prepared by electrodeposition and low‐pressure chemical vapor deposition is applied as an active material in flexible supercapacitors. The grown MWCNT effectively maintains the hierarchical structure of the MXene and accelerates electron transport in the electrode. Based on the excellent synergetic effect between MXene and MWCNTs, the work can provide a new route toward improving the electrochemical performance of MXene.