Anisotropic carbon materials such as carbon nanotubes (CNTs) and carbon fibers exhibit extremely high thermal conductivity (TC). However, due to their high electrical conductivity, they have not been used in applications that require both high TC and electrical insulation. Herein, ultra-highly electrically insulating CNTs were prepared by layer-by-layer self-assembly method using various oxide nanomaterials (ONMs) such as titania nanosheets, silica nanoparticles, and water glasses (WGs). ONM-coated CNTs (ONM-CNTs) showed high surface resistivity and ultra-high volume resistivity in acrylate polymer matrices (∼10¹⁷ Ω cm) even at high CNT loadings (∼10 vol%). WG-coated CNTs (WG-CNTs) after calcination exhibited the highest heat resistance, showing high electrical insulation even after heat treatment at 500 °C under air. WG-CNTs were stable in the poly (1,4-phenylenesulfide) (PPS) matrix during melt-mixing at high temperature (300 °C), giving the WG-CNT/PPS composites with extremely high volume resistivity (≥10¹⁵ Ω cm) even at high WG-CNT loadings (∼16.7 vol%) and enhanced through-plane TC (∼2.0 W m⁻¹ K⁻¹). The TC is much superior to those of previously reported CNT/polymer composites with electrical insulation (≤0.57 W m⁻¹ K⁻¹). This method is scalable, nondestructive, and applicable to various carbon materials. The presented approach is promising for preparing electrically insulating materials for various thermal management applications.

碳纳米管 (CNT) 和碳纤维等各向异性碳材料表现出极高的热导率 (TC)。然而，由于它们的高导电性，它们尚未用于需要高 TC 和电绝缘的应用中。在此，使用各种氧化物纳米材料（ONMs），如二氧化钛纳米片、二氧化硅纳米颗粒和水玻璃（WGs），通过逐层自组装方法制备了超高电绝缘碳纳米管。ONM 涂层的碳纳米管 (ONM-CNTs) 在丙烯酸酯聚合物基质中显示出高表面电阻率和超高体积电阻率 (~10 ¹⁷ Ω cm)，即使在高 CNT 负载（~10 vol%）下。煅烧后的 WG 涂层碳纳米管 (WG-CNTs) 表现出最高的耐热性，即使在空气中 500 °C 下热处理后也显示出高电绝缘性。WG-CNTs 在高温 (300 °C) 熔融混合过程中在聚 (1,4-苯硫醚) (PPS) 基质中是稳定的，使 WG-CNT/PPS 复合材料具有极高的体积电阻率（≥10 ¹⁵  Ω cm)，即使在高 WG-CNT 负载（~16.7 vol%）和增强的贯通面 TC（~2.0 W m ^-1  K ^-1）。TC 远优于先前报道的具有电绝缘性 (≤0.57 W m ^-1  K ^-1）。该方法具有可扩展性、无损性，适用于各种碳材料。所提出的方法有望为各种热管理应用制备电绝缘材料。