Highly thermal conductivity materials with excellent electromagnetic interference shielding and Joule heating performances are ideal for thermal management in the next generation of communication industry, artificial intelligence and wearable electronics. In this work, thermal conductivity silver nanowires (AgNWs) are prepared by polyol thermal method using silver nitrate as the silver source and ethylene glycol as the solvent and reducing agent, and boron nitride (BN) is taken as raw material to prepare thermal conductivity and insulating boron nitride nanosheets (BNNS) with the help of isopropyl alcohol (IPA) and ultrasonication-assisted peeling method, which are compounded with aramid nanofibers (ANF) prepared by chemical dissociation, respectively, and the (BNNS/ANF)-(AgNWs/ANF) thermal conductivity and electromagnetic interference shielding composite films with Janus structure are prepared by the “vacuum-assisted filtration and hot pressing” method. The results show that Janus (BNNS/ANF)-(AgNWs/ANF) thermal conductivity and electromagnetic interference shielding composite films exhibit “one side insulating, one side conducting” properties, the surface resistivity of the BNNS/ANF surface is 4.7×1013 Ω, while the conductivity of the AgNWs/ANF surface is 5275 S/cm. The (BNNS/ANF)-(AgNWs/ANF) thermal conductivity and electromagnetic interference shielding composite film with thickness of 95 μm has a high in-plane thermal conductivity coefficient of 8.12 W/(m·K) and excellent electromagnetic interference shielding performance of 70 dB. The composite film also has excellent mechanical properties (tensile strength and tensile modulus of 122.9 MPa and 2.7 GPa, respectively). It also has good temperature-voltage response characteristics (high Joule heating temperature at low supply voltage (5 V, 215.0oC), fast response time (10 s)), excellent electrical stability and reliability (stable and constant real-time relative resistance under up to 300 cycles and 1500 s of tensile-bending fatigue work tests).

兼具优异电磁屏蔽性能和焦耳热性能的高导热材料是下一代通讯工业、人工智能和可穿戴电子产品领域中理想的热管理材料。本文以硝酸银为银源、乙二醇为溶剂和还原剂，采用多元醇热法制备导热导电银纳米线（AgNWs），并以氮化硼（BN）为原料，借助异丙醇（IPA）及超声辅助剥离法制备导热绝缘氮化硼纳米片（BNNS），分别与化学解离制备的芳纶纳米纤维（ANF）复合，经“真空辅助抽滤-热压”法制备具有Janus结构的(BNNS/ANF)-(AgNWs/ANF)导热屏蔽复合膜。结果表明，Janus (BNNS/ANF)-(AgNWs/ANF)导热屏蔽复合膜展现出“一面绝缘、一面导电”特性，BNNS/ANF面表面电阻率为4.7×1013 Ω，而AgNWs/ANF面电导率为5275 S/cm。95 μm厚的(BNNS/ANF)-(AgNWs/ANF)导热屏蔽复合膜具有8.12 W/(m·K)的高面内热导率和70 dB的卓越电磁屏蔽效能。该复合膜还具有优异的力学性能（拉伸强度和拉伸模量分别为122.9 MPa和2.7 GPa），良好的温度-电压响应特性（如低供电电压下的高焦耳加热温度（5 V、215.0oC）、快速响应时间（10 s）），优异的电稳定性和可靠性（长达300次、1500 s的拉伸-弯曲疲劳工作试验下表现出稳定和恒定的实时相对电阻）。