Kang Dong Jun, Lee Ki Hyun, Noh Sung Hyun, Shin Hwansoo, Jeong Woojae, Lee Hyeonhoo, Seo Yeongbhin, Han Tae Hee
Department of Organic and Nano Engineering, Human-Tech Convergence Program, Hanyang University, Seoul, 04763, Republic of Korea.
Research Institute of Industrial Science, Hanyang University, Seoul, 04763, Republic of Korea.
Small. 2023 Nov;19(44):e2301077. doi: 10.1002/smll.202301077. Epub 2023 Jul 4.
A Joule heater made of emerging 2D nanosheets, i.e., MXene, has the advantage of low-voltage operation with stable heat generation owing to its highly conductive and uniformly layered structure. However, the self-heated MXene sheets easily get oxidized in warm and moist environments, which limits their intrinsic heating efficiencies. Herein, an ultrathin graphene skin is introduced as a surface-regulative coating on MXene to enhance its oxidative stability and Joule heating efficiency. The skin layer is deposited on MXene using a scalable solution-phased layer-by-layer assembly process without deteriorating the excellent electrical conductivity of the MXene. The graphene skin comprises narrow and hydrophobic channels, which results in ≈70 times higher water impermeability of the hybrid film of graphene and MXene (GMX) than that of the pristine MXene. A complementary electrochemical analysis confirms that the graphene skin facilitates longer-lasting protection than conventional polymer coatings owing to its tortuous pathways. In addition, the sp planar carbon surface with a low heat loss coefficient improves the heating efficiency of the GMX, indicating that this strategy is promising for developing adaptive heating materials with a tractable voltage range and high Joule heating efficiency.
由新兴的二维纳米片（即MXene）制成的焦耳加热器，由于其高导电性和均匀的层状结构，具有低电压运行且发热稳定的优点。然而，自热的MXene片在温暖潮湿的环境中容易被氧化，这限制了它们的固有加热效率。在此，引入超薄石墨烯表皮作为MXene上的表面调节涂层，以提高其氧化稳定性和焦耳加热效率。通过可扩展的溶液相逐层组装工艺将表皮层沉积在MXene上，而不会降低MXene优异的导电性。石墨烯表皮包含狭窄且疏水的通道，这使得石墨烯与MXene的混合膜（GMX）的不透水性比原始MXene高约70倍。互补的电化学分析证实，由于其曲折的路径，石墨烯表皮比传统聚合物涂层提供更持久的保护。此外，具有低热损失系数的sp平面碳表面提高了GMX的加热效率，表明该策略对于开发具有易于控制的电压范围和高焦耳加热效率的自适应加热材料具有前景。
