The localized overheating of high-power and miniaturized electronic devices puts a pressing demand for developing organic phase change composites with rapid and uniform heat conduction. Herein, we constructed a bidirectionally oriented and interconnected boron nitride nanosheet (BNNS) network to obtain highly and uniformly thermal conductive phase change composites. The edge-center temperature gradient generated during freezing via a radial ice-template strategy actuated the BNNSs to radially align. The simultaneously appearing bottom-up temperature gradient induced BNNSs to closely stack along the vertical direction. The formed biaxially oriented and interlaced BNNS network in poly(ethylene glycol) (PEG) composites formed rapid and macroscopically uniform heat transfer pathways. The resultant phase change composite loaded with 5.1 vol % BNNSs exhibited the in-plane and through-plane thermal conductivities of 1.62 and 1.45 W/mK respectively, nearly 150% higher than that of the randomly distributed counterpart. The strong thermal conductive stability after intense thermal shock, favorable shape stability, and large latent heat were also gathered. Our work offers a valuable reference for developing desired thermal conductive phase change composites for efficient thermal management.

中文翻译：

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通过构建双向取向互连氮化硼纳米片网络实现高度均匀导热相变复合材料


高功率和小型化电子设备的局部过热迫切需要开发具有快速且均匀导热的有机相变复合材料。在此，我们构建了双向取向且互连的氮化硼纳米片（BNNS）网络，以获得高度均匀的导热相变复合材料。冷冻过程中通过径向冰模板策略产生的边缘-中心温度梯度促使 BNNS 径向排列。同时出现的自下而上的温度梯度导致BNNSs沿着垂直方向紧密堆叠。在聚乙二醇（PEG）复合材料中形成的双轴取向和交错的BNNS网络形成了快速且宏观均匀的传热路径。负载 5.1 vol% BNNS 的所得相变复合材料的面内和面内热导率分别为 1.62 和 1.45 W/mK，比随机分布的对应物高近 150%。还具有强烈热冲击后的强导热稳定性、良好的形状稳定性和大的潜热。我们的工作为开发所需的导热相变复合材料以实现高效的热管理提供了宝贵的参考。