The discovery of liquid crystalline (LC) phases in dispersions of two-dimensional (2D) materials has enabled the development of macroscopically aligned three-dimensional (3D) macrostructures. Here, we report the first experimental observation of self-assembled LC phases in aqueous Ti3C2T x MXene inks without using LC additives, binders, or stabilizing agents. We show that the transition concentration from the isotropic to nematic phase is influenced by the aspect ratio of MXene flakes. The formation of the nematic LC phase makes it possible to produce fibers from MXenes using a wet-spinning method. By changing the Ti3C2T x flake size in the ink formulation, coagulation bath, and spinning parameters, we control the morphology of the MXene fibers. The wet-spun Ti3C2T x fibers show a high electrical conductivity of ∼7750 S cm-1, surpassing existing nanomaterial-based fibers. A high volumetric capacitance of ∼1265 F cm-3 makes Ti3C2T x fibers promising for fiber-shaped supercapacitor devices. We also show that Ti3C2T x fibers can be used as heaters. Notably, the nematic LC phase can be achieved in other MXenes (Mo2Ti2C3T x and Ti2CT x ) and in various organic solvents, suggesting the widespread LC behavior of MXene inks.

中文翻译：

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无添加剂MXene液晶和纤维。

二维（2D）材料分散液中液晶（LC）相的发现使宏观对齐的三维（3D）宏观结构得以发展。在这里，我们报告了在不使用LC添加剂，粘合剂或稳定剂的情况下，水性Ti3C2T x MXene油墨中自组装LC相的首次实验观察。我们表明，从各向同性相到向列相的过渡浓度受MXene片的长径比影响。向列LC相的形成使得可以使用湿纺法从MXene生产纤维。通过改变油墨配方，凝结浴和纺丝参数中的Ti3C2T x薄片尺寸，我们可以控制MXene纤维的形态。Ti3C2T x湿纺纤维显示出约7750 S cm-1的高电导率，超越现有的基于纳米材料的纤维。约1265 F cm-3的高体积电容使Ti3C2T x纤维有望用于纤维状超级电容器设备。我们还表明，Ti3C2T x纤维可用作加热器。值得注意的是，向列型LC相可以在其他MXene（Mo2Ti2C3Tx和Ti2CTx）中以及在各种有机溶剂中实现，这表明MXene油墨具有广泛的LC行为。