Xu Wenting, Xu Zhao, Liang Yunxia, Liu Lianmei, Weng Wei
State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Materials Science and Engineering, Donghua University, Shanghai 201620, People's Republic of China.
Key Laboratory of Yarn Materials Forming and Composite Processing Technology of Zhejiang Province, College of Material and Textile Engineering, Jiaxing University, Zhejiang 314001, People's Republic of China.
Nanotechnology. 2021 Jun 11;32(35). doi: 10.1088/1361-6528/ac04cf.
Nowadays, it is highly desirable to achieve high strength, flexibility and electrochemical performance for supercapacitor electrodes simultaneously. Herein, few-layer MXene flakes are assembled into free-standing films by facile vacuum-filtration method, in which hydrophilic-functionalized carbon nanotubes (CNTs) are further incorporated. The morphology of MXene/CNT composite films evolves from compact to 'CNT in MXene' to laminar to 'MXene in CNT' and finally to separate structures when increasing the CNT weight percentage. Among them, the laminar structure in which thin MXene and CNT layers are stacked alternately is demonstrated to be the best. The laminar MXene/CNT film possesses much higher strength, elongation and specific capacitance than MXene film due to the engineered porosity, good interaction between MXene flakes and CNTs, and proper CNTs' distribution. As a result, high specific capacitance of 423.4 F gat 1 A gand capacitance retention of nearly 60% at 10 A gare accomplished. Moreover, the composite film is flexible and withstands bending up to 180°, indicating that the proposed laminar MXene/CNT composite film is a superb candidate for flexible supercapacitors.
如今，同时实现超级电容器电极的高强度、柔韧性和电化学性能是非常理想的。在此，通过简便的真空过滤法将几层MXene薄片组装成独立的薄膜，并进一步引入亲水性功能化碳纳米管（CNT）。当增加CNT的重量百分比时，MXene/CNT复合薄膜的形态从致密结构演变为“CNT在MXene中”结构，再到层状结构，然后变为“MXene在CNT中”结构，最终变为分离结构。其中，薄的MXene层和CNT层交替堆叠的层状结构表现最佳。由于设计的孔隙率、MXene薄片与CNT之间良好的相互作用以及CNT的适当分布，层状MXene/CNT薄膜比MXene薄膜具有更高的强度、伸长率和比电容。结果，在1 A g时实现了423.4 F g的高比电容，在10 A g时电容保持率接近60%。此外，该复合薄膜具有柔韧性，可承受高达180°的弯曲，这表明所提出的层状MXene/CNT复合薄膜是柔性超级电容器的极佳候选材料。
