Highly thermally conductive and flexible phase change composites enabled by polymer/graphite nanoplatelet-based dual networks for efficient thermal management
Highly thermally conductive and flexible phase change composites enabled by polymer/graphite nanoplatelet-based dual networks for efficient thermal management
复制标题
基于聚合物/石墨纳米片的双网络实现高导热性和柔性相变复合材料，可实现高效的热管理
DOI：
10.1039/d0ta05904h
复制
发表时间：
2020-10-14
影响因子：
11.9
通讯作者：
Wang, Ruzhu
中科院分区：
文献类型：
--
作者：
Wu, Si;Li, Tingxian;Wang, Ruzhu
相变材料由于在相变点附近具有较高的潜热容量而被广泛应用于被动热管理和能量存储。然而，低导热性和泄漏问题是基于PCM的热相关应用中的两个长期存在的瓶颈。尽管现有技术可以通过合成相变复合材料（PCC）来解决这些问题中的一个或两个，但是实现同时具有上级热性能和机械性能以及相变行为的高性能PCC仍然具有挑战性。在这项工作中，报道了一种新的方法来制备高导热，灵活和防漏的PCCs通过构建二元聚合物和石墨纳米片网络作为功能的PCMs的基质。在复合材料中，石蜡作为PCM，大分子烯烃嵌段共聚物（OBC）形成交联聚合物网络以包围熔融PCM并赋予复合膜柔性，并且具有长链结构的膨胀石墨（EG）形成对齐且互连的石墨纳米片逾渗网络以实现PCCs的高导热性。当EG含量为5- 40wt%时，径向导热系数达到4.2- 32.8W·m（-1）·K（-1）。所得到的柔性复合膜通过在高放电速率下将商用锂离子电池的工作温度降低超过12摄氏度而显示出有效且可靠的热管理性能。我们的工作为合成高性能PCC提供了一种高效且具有成本效益的途径，用于各种与热相关的应用，包括可再生能源的热收集，建筑能源管理，电子产品的热管理等。
Phase change materials (PCMs) have been widely used for passive thermal management and energy storage due to the high latent heat capacity near phase transition points. However, the low thermal conductivity and leakage issue are two long-standing bottlenecks in PCM-based heat-related applications. Although the state of the art can address one or both of these issues by synthesizing phase change composites (PCCs), it remains challenging to achieve high-performance PCCs with simultaneously superior thermal and mechanical properties and phase change behaviors. In this work, a new method is reported to prepare highly thermally conductive, flexible and leakage-proof PCCs by constructing dual polymer and graphite nanoplatelet networks as the functional matrix of PCMs. In the composites, paraffin wax serves as the PCM, the macromolecular olefin block copolymer (OBC) forms a cross-linked polymer network to enclose the molten PCM and endow the composite film with flexibility, and expanded graphite (EG) with a long-chain structure forms an aligned and interconnected graphite nanoplatelet percolation network to enable the high thermal conductivity of PCCs. The radial thermal conductivities reach 4.2-32.8 W m(-1)K(-1)at EG loadings of 5-40 wt%. The resultant flexible composite film shows efficient and reliable thermal management performance by lowering the working temperature of a commercial lithium-ion battery by more than 12 degrees C at high discharge rates. Our work provides an efficient and cost-effective route to synthesizing high-performance PCCs for various heat-related applications including the thermal harvesting of renewable energy, building energy management, thermal management of electronics,etc.