摘要
为拓展二维碳化钛材料在智能纺织品中的应用,以纤维素非织造布为基材,将Ti3C2Tx和碳纳米管(CNTs)喷涂在纤维素非织造布上,制备出一种集传感、储能、热能转换于一体的多功能复合导电织物.借助扫描电子显微镜、X射线衍射仪及傅里叶变换红外光谱仪对Ti3C2Tx及其改性织物的表面形貌及结构进行表征.结果表明:Ti3C2Tx/CNTs/非织造布具有优异的电热和光热转化性能,在15 V电压下织物快速升温至115 ℃,且在室温(32 ℃)条件下,织物经阳光照射后表面快速升温至65℃;所制备的柔性半固态超级电容器,在电流密度为0.2 A/cm2下,最大面积比电容达到125 mF/cm2,即使在10 000次充放电循环后仍保持74%的电容;作为应变传感器时,表现出明显的负电阻变化和高灵敏度,能准确检测出手指弯曲、肘部弯曲、膝盖弯曲等人体动作.
Abstract
Objective The two-dimensional material MXene can be easily integrated with textiles because of its excellent dispersion,good mechanical properties,and high conductivity,and has shown potential applications in many areas.In order to expand the application of two-dimensional titanium carbide materials into smart textiles,Ti3C2Tx and carbon nanotubes(CNTs)were sprayed on pure nonwovens as the substrate to prepare a multifunctional electronic textile which integrates sensing,energy storage,and thermal energy conversion.Method Ti3C2Tx MXene sheets were synthesized through the typical chemical etching method by selectively etching Al layer from Ti3AlC2 phase.Ti3C2Tx(2 mg/mL)and CNTs dispersion(2 mg/mL)were then ultrasonically mixed(at a volume ratio of 1∶1)and repeatedly sprayed on nonwoven fabric substrate until the surface resistance of the fabric was lower than 150 Ω.The Ti3C2Tx/CNTs/nionwoveni(MCF)composite was finally prepared and characterized by scanning electron microscope and X-ray diffraction.In addition,the photothermal and electrothermal conversion performance,electrochemical properties and sensing performance were also explored.Results The thread-like CNTs on the fabric surface were wrapped around the entangled Ti3C2Tx flake,connecting Ti3C2Tx from different regions and forming a stable conductive network.The Ti3C2Tx was successfully synthesized and uniformly attached on the surface of nonwoven substrate.When MCF was used for photothermal conversion,it was quickly heated up to 65 ℃ in 60 min and maintained stable.In terms of the electrical heating performance,the thermal response time of MCF was shorter than 2 s,and the aperture on the infrared thermal image was uniformly distributed.The reason is that the addition of CNTs further improved the overall conductivity of the material,and exploited the large volume and contact area of the CNTs to bond with more Ti3C2Tx,and created more conductive pathways on the surface of the fabric.When the MCF electrode was used in a flexible semi-solid supercapacitor,the specific capacitance remained at 70 mF/cm2 even at a high current density of 2 A/cm2.After 10 000 cycles,the MCF still maintained a capacitance retention of 74%,indicating that the MCF electrode had a good cycling durability.In addition,the MCF was also used as sensors and fixed on the neck,wrist,fingertips,knee,and elbow of the human body to monitor human motions.With each bending of the human body,the resistances of MCF underwent regular changes,which were captured and recorded clearly and stably.Conclusion MCF was successfully prepared by modified mixed solution of CNTs/Ti3C2Tx on the nonwoven substrate using a simple spraying method.Owing to the synergistic effect of CNTs and MXene films,MCF was rapidly heated up to 65 ℃ at room temperature of 32 ℃ after being exposed to sunlight and 1 15 ℃ under a voltage of 15 V,demonstrating good photothermal conversion and joule thermal performance.When used as a flexible semi-solid supercapacitor electrode,MCF exhibited a high specific capacitance of 125 mF/cm2.Additionally,MCF could be applied as a flexible strain sensor to detect human motions,exhibiting significant negative resistance changes and high sensitivity.In summary,MCF presents great potential applications in wearable electronic products and multifunctional garments.