C/MoS2@Ti3C2Tx composite flexible films for high performance supercapacitors

Abstract

Two-dimensional (2D) Ti3C2Tx MXene has important potential applications in supercapacitor due to its high electrical conductivity, good hydrophilicity and abundant surface functional groups. It can be prepared into films of flexible electrochemical capacitors without adhesives. However, the self-stacking of Ti3C2Tx nanosheets seriously reduces their capacitance. Here, we developed a novel structure of the flexible material C/MoS2@Ti3C2Tx through facile physical mixing, three-dimensional C/MoS2 nanoflowers were successfully inserted between two-dimensional Ti3C2Tx layers. The self-stacking of MoS2 and Ti3C2Tx attenuates simultaneously. And these two materials form a particle-layer structure. At a current density of 0.5 A/g, the freestanding C/MoS2@Ti3C2Tx film has an excellent specific capacitance of 410 F g−1, which is 2.6 times that of C/MoS2 and 1.9 times that of Ti3C2Tx, respectively. It remains in good condition after 5000 cycles at 10 A/g, demonstrating excellent long-life cycle stability. The improvement of electrochemical performance is attributed to the particle-layer structure, which effectively avoids the re-packing of Ti3C2Tx and greatly reduces the diffusion distance of electrolyte ions. Furthermore, the addition of C/MoS2 nanoflowers has no effect on the bending ability of MXene composite films. And The nano-flower-like structure of C/MoS2 provides high electric double layer capacitance performance. This study provides new ideas for Ti3C2Tx-based films in the field of energy storage and wearable devices.