Free-Standing, Flexible Carbon@MXene Films with Cross-Linked Mesoporous Structures toward Supercapacitors and Pressure Sensors

Abstract

The preparation of multifunctional materials with low cost and simple synthesis processes is still challenging. Herein, by employing various sizes (50–500 nm) of polystyrene (PS) spheres as templates, different free-standing carbon@MXene films with three-dimensional (3D) mesoporous structures were fabricated through a simple multistep route. The microstructure, composition, mechanical property, conductivity, electrochemical activity, and sensing characteristics of these carbon@MXene films were investigated in detail. The intercalation of the PS spheres can effectively reduce the self-accumulation of MXene nanosheets and construct 3D cross-linked mesoporous structures, therefore broadening the ion transport channels and exposing more active sites of carbon@MXene films. When applied in a symmetrical supercapacitor, the optimized carbon@MXene electrode has a satisfactory specific capacitance of 447.67 F g–1 at a current density of 1 A g–1. Moreover, the 3D mesoporous structures of carbon@MXene films can significantly improve the sensitivity of the resultant pressure sensors with excellent stability (10,000 cycles). Thus, such mesoporous carbon@MXene films prepared by a facile yet robust route will be a versatile material for many applications.

The Emergence of 2D MXenes Based Zn‐Ion Batteries: Recent Development and Prospects

“…Reproduced with permission. [ 44 ] Copyright 2021, American Chemical Society. d) Electrochemical etching method.…”

“…Bai et al., using polystyrene (PS), fabricated a 3D self‐supporting film of carbon@MXene with mesoporous structure via a facile vacuum filtration process. [ 59 ] The composition, microstructure, mechanical property, electrochemical activity, conductivity, and sensing characteristics of carbon@MXene film through various sizes and mass load were investigated in detail. Figure 4c shows the construction of the 3D mesoporous structure of self‐supporting carbon@MXene film through a multistep method.…”

“…c) Vacuum filtration method in LiF/HCl. Reproduced with permission [44]. Copyright 2021, American Chemical Society.…”

Multifunctional Integrated Interdigital Microsupercapacitors and Self-Powered Iontronic Tactile Pressure Sensor for Wearable Electronics

“…4 Bai et al demonstrate free-standing carbon@ MXene films with three-dimensional (3D) mesoporous structures for symmetrical supercapacitor and pressure sensors. 9 However, each function of most integrated devices is independent, and multiple processes are required, which increases cost and the complexity of device integration. Therefore, realizing multifunctionality for wearable electronics in one device is attractive, and designing functional materials with dual properties is a considerable challenge.…”

“…15 However, it is inevitable to generate self-stacking due to the strong van der Waals force interaction between MXene nanosheets, which severely reduces surface active sites of MXene electrodes and hinders ion diffusion, thus limiting their performance. 9,16 Effective use of "spacers" strategy has been adopted to modify composite structure of MXene electrodes. 11,17 TiS 2 is in layered structure formed by S−M−S lamellae; various research on TiS 2 illustrates that sufficient layer spacing is conducive to ion transport.…”