The challenges of leakage and low thermal conductivity have emerged as obstacles that hinder the advancement of long-term thermal stability and versatility of phase change material (PCM). This study aims to address the challenges of high leakage rate and low thermal conductivity associated with paraffin wax (PW) in phase change energy storage. A composite PCM with a layered microstructure was successfully synthesized by physically blending expanded graphite (EG), covalent triazine framework (CTF), and adsorbed PW. For the first time, the encapsulation of (phase change materials) PCMs using covalent organic frameworks (COF) was realized. Subsequently, various aspects of the prepared materials were thoroughly characterized and analyzed, demonstrating excellent performance. The material exhibited a leakage rate of only 0.18 %, a thermal conductivity approximately 10 times higher than that of pure PW, and a high latent heat of phase change (111.26 J/g). After undergoing 500 thermal cycles of storage and release, the latent heat of phase change remained stable at around 72 %, indicating robust thermal cycle stability. Furthermore, photothermal tests revealed an impressive photothermal conversion efficiency of 86.9 % for the composite PCM, highlighting its remarkable photothermal conversion capability and efficiency. This study provides an innovative solution to the challenges of high leakage rate and low thermal conductivity in paraffin-based phase change energy storage. Additionally, it delivers valuable theoretical guidance and an experimental foundation for the development of more efficient and stablePCMs.

中文翻译：

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通过三维多孔层状共价三嗪骨架/膨胀石墨复合材料协同增强相变材料，用于太阳能存储及其他领域

泄漏和低热导率的挑战已成为阻碍相变材料（PCM）长期热稳定性和多功能性进步的障碍。本研究旨在解决相变储能中与石蜡（PW）相关的高泄漏率和低导热率的挑战。通过物理共混膨胀石墨（EG）、共价三嗪骨架（CTF）和吸附PW，成功合成了具有层状微结构的复合相变材料。首次实现了使用共价有机框架（COF）封装（相变材料）PCM。随后，对所制备材料的各个方面进行了彻底的表征和分析，显示出优异的性能。该材料的泄漏率仅为0.18%，导热系数比纯PW高约10倍，并且具有很高的相变潜热（111.26 J/g）。经过500次储存和释放热循环后，相变潜热保持稳定在72%左右，表明具有良好的热循环稳定性。此外，光热测试显示复合PCM的光热转换效率高达86.9%，凸显了其卓越的光热转换能力和效率。这项研究为石蜡基相变储能中高泄漏率和低导热率的挑战提供了创新的解决方案。此外，它还为开发更高效、更稳定的相变材料提供了宝贵的理论指导和实验基础。