Efficient thermal energy harvesting using phase-change materials (PCMs) has great potential for cost-effective thermal management and energy storage applications. However, the low thermal conductivity of PCMs (KPCM ) is a long-standing bottleneck for high-power-density energy harvesting. Although PCM-based nanocomposites with an enhanced thermal conductivity can address this issue, achieving a higher K (>10 W m-1 K-1 ) at filler loadings below 50 wt% remains challenging. A strategy for synthesizing highly thermally conductive phase-change composites (PCCs) by compression-induced construction of large aligned graphite sheets inside PCCs is demonstrated. The millimeter-sized graphite sheet consists of lateral van-der-Waals-bonded and oriented graphite nanoplatelets at the micro/nanoscale, which together with a thin PCM layer between the sheets synergistically enhance KPCM in the range of 4.4-35.0 W m-1 K-1 at graphite loadings below 40.0 wt%. The resulting PCCs also demonstrate homogeneity, no leakage, and superior phase change behavior, which can be easily engineered into devices for efficient thermal energy harvesting by coordinating the sheet orientation with the thermal transport direction. This method offers a promising route to high-power-density and low-cost applications of PCMs in large-scale thermal energy storage, thermal management of electronics, etc.

中文翻译：

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大型定向石墨片的高性能导热相变复合材料，可扩展热能收集。

使用相变材料（PCM）进行有效的热能收集对于具有成本效益的热管理和能量存储应用具有巨大的潜力。但是，PCM（KPCM）的低导热率是高功率密度能量收集的长期瓶颈。尽管具有增强的导热性的基于PCM的纳米复合材料可以解决此问题，但在低于50 wt％的填料载荷下实现更高的K（> 10 W m-1 K-1）仍然具有挑战性。演示了通过压缩诱导在PCC内部构造大尺寸石墨片来合成高导热相变复合材料（PCC）的策略。毫米大小的石墨片由范德华力键合的侧向和定向的微米/纳米级石墨纳米片组成，当石墨含量低于40.0 wt％时，它们与薄板之间的PCM薄层协同作用，可在4.4-35.0 W m-1 K-1的范围内协同增强KPCM。所得的PCC还显示出均匀性，无泄漏和出色的相变行为，可通过将薄片的方向与热传输方向进行协调，轻松地将其设计为有效进行热能收集的设备。该方法为PCM在大规模热能存储，电子器件的热管理等方面的高功率密度和低成本应用提供了一条有希望的途径。通过将薄片的方向与热传输方向相协调，可以很容易地将其设计成有效收集热能的设备。该方法为PCM在大规模热能存储，电子器件的热管理等方面的高功率密度和低成本应用提供了一条有希望的途径。通过将薄片的方向与热传输方向相协调，可以很容易地将其设计成有效收集热能的设备。该方法为PCM在大规模热能存储，电子器件的热管理等方面的高功率密度和低成本应用提供了一条有希望的途径。