Sun Yue, Li Xingxing, Ren Zihan
Key Laboratory of Green and Precise Synthetic Chemistry and Applications, Ministry of Education, College of Chemistry and Materials Science, Huaibei Normal University, Huaibei, Anhui 235000, People's Republic of China.
Nanotechnology. 2024 Jun 21;35(36). doi: 10.1088/1361-6528/ad5728.
Two-dimensional (2D) transition metal carbides and nitrides (MXenes) are a class of 2D nanomaterials that can offer excellent properties for high-performance supercapacitors. Nevertheless, irreversible restacking of MXene sheets decreases the interlayer spacing, which inhibits the ion intercalation between the MXene nanosheets and finally deteriorates the electrochemical performance of supercapacitors. Herein, aramid nanofibers (ANFs) are mixed with TiCTMXene to prepare MXene/ANFs composite films. The restacking of MXene sheets is inhibited by the electrostatic repulsion between ANFs and MXene. The ANFs act as intercalation agents to increase the interlayer spacing of the composite films, which can improve the ion storage ability of supercapacitors. Furthermore, the ANFs enhance the mechanical strength of the composite films due to the strong hydrogen bonding interaction and nanomechanical interlocking between ANFs and MXene, endowing the composite films with self-standing property. The resultant composite films are used as electrodes for flexible solid-state supercapacitors to achieve high specific capacitance (996.5 mF cmat 5 mV s) and outstanding cycling stability. Thus, this work provides a potential strategy to regulate the properties of 2D nanomaterials, which may expand the application of them in energy storage, ionic separation, osmotic energy conversion and beyond.
二维（2D）过渡金属碳化物和氮化物（MXenes）是一类可为高性能超级电容器提供优异性能的二维纳米材料。然而，MXene片层的不可逆重新堆叠会减小层间距，这会抑制离子在MXene纳米片之间的嵌入，最终降低超级电容器的电化学性能。在此，将芳纶纳米纤维（ANFs）与TiCTMXene混合以制备MXene/ANFs复合薄膜。ANFs与MXene之间的静电排斥作用抑制了MXene片层的重新堆叠。ANFs作为嵌入剂增加了复合薄膜的层间距，这可以提高超级电容器的离子存储能力。此外，由于ANFs与MXene之间强烈的氢键相互作用和纳米机械互锁，ANFs增强了复合薄膜的机械强度，赋予复合薄膜自立性能。所得复合薄膜用作柔性固态超级电容器的电极，以实现高比电容（5 mV s时为996.5 mF cm）和出色的循环稳定性。因此，这项工作提供了一种调节二维纳米材料性能的潜在策略，这可能会扩大它们在能量存储、离子分离、渗透能转换等领域的应用。
