Copper/epoxy (Cu/epoxy) composite is a kind of important thermal management material due to its high thermal conductivity, excellent mechanical robustness and low cost. However, susceptibility of Cu to oxygen and high electric leakage loss of Cu urgently require a protective interfacial layer with anti-oxidation and electric insulation properties. Currently, the reported interfacial layers for Cu fillers either are prepared under harsh condition or possess inferior insulation/thermal resistant properties. Here, we propose a strategy to prepare dense silica interfacial layer containing Si-NH-Si/Si-H reactive groups for Cu/epoxy composite, which not only protects Cu from oxidation but also tethers Cu and epoxy with covalent bonds. Compared with Cu/epoxy composite, the as-prepared Cu@silica/epoxy composite exhibits enhanced thermal conductivity, high temperature stability without decrease of thermal conductivity at 150 °C for 200 h, and improved dielectric performance with dielectric permittivity and loss of 13.1 and 0.1 at 100 Hz, respectively. This work provides an efficient approach to covalently bond interfacial layer for simultaneously improving thermal and dielectric property of Cu/epoxy composite, showing high potential for real application.

铜/环氧树脂（Cu/epoxy）复合材料具有高导热性、优异的机械强度和低成本，是一种重要的热管理材料。然而，铜对氧的敏感性和铜的高漏电损失迫切需要具有抗氧化和电绝缘性能的保护界面层。目前，所报道的用于 Cu 填料的界面层要么是在苛刻的条件下制备的，要么具有较差的绝缘/耐热性能。在这里，我们提出了一种制备含有 Si-NH-Si/Si-H 反应基团的致密二氧化硅界面层的策略，用于 Cu/环氧树脂复合材料，它不仅可以保护 Cu 不被氧化，而且还可以通过共价键连接 Cu 和环氧树脂。与Cu/环氧树脂复合材料相比，所制备的Cu@silica/环氧树脂复合材料具有更高的导热性，在 150°C 下保持 200 小时的高温稳定性不会降低热导率，并且提高了介电性能，在 100 Hz 下的介电常数和损耗分别为 13.1 和 0.1。这项工作为共价键合界面层提供了一种有效的方法，可同时提高铜/环氧树脂复合材料的热和介电性能，显示出实际应用的巨大潜力。