The high electrical conductivity and good chemical stability of MXenes offer hopes for their use in many applications, such as wearable electronics, energy storage, and electromagnetic interference shielding. While their optical, electronic, and electrochemical properties have been widely studied, information on the thermal properties of MXenes is scarce. In this study, we investigate the heat transport properties of Ti₃C₂T_x MXene single flakes using scanning thermal microscopy and find exceptionally low anisotropic thermal conductivities within the Ti₃C₂T_x flakes, leading to an effective thermal conductivity of 0.78 ± 0.21 W m^–1 K^–1. This observation is in stark contrast to the predictions of the Wiedemann–Franz law, as the estimated Lorenz number is only 0.25 of the classical value. Due to the combination of low thermal conductivity and low emissivity of Ti₃C₂T_x, the heat loss from it is 2 orders of magnitude smaller than that from common metals. Our study explores the heat transport mechanisms of MXenes and highlights a promising approach for developing thermal insulation, two-dimensional thermoelectric, or infrared stealth materials.

中文翻译：

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违反 Wiedemann-Franz 定律和 Ti3C2Tx MXene 的超低热导率


MXenes 的高导电性和良好的化学稳定性为它们在许多应用中的使用带来了希望，例如可穿戴电子产品、储能和电磁干扰屏蔽。虽然它们的光学、电子和电化学特性已被广泛研究，但关于 MXenes 热特性的信息却很少。在这项研究中，我们使用扫描热显微镜研究了 Ti₃C₂T_x MXene 单片的热传递特性，发现 Ti₃C₂T_x 薄片内的各向异性导热系数极低，导致有效导热系数为 0.78 ± 0.21 W m^–1 K^–1.这一观察结果与 Wiedemann-Franz 定律的预测形成鲜明对比，因为估计的洛伦兹数仅为经典值的 0.25。由于 Ti₃C₂T_x 的低导热性和低发射率的组合，它的热损失比普通金属的热损失小 2 个数量级。我们的研究探讨了 MXenes 的热传输机制，并强调了一种开发隔热、二维热电或红外隐形材料的有前途的方法。