Phase change materials (PCMs) with thermal energy storage property are vital in solar-thermal energy conversion and utilization systems. However, low thermal conductivity, low light absorption, and severe brittleness are major application-hindering factors. In this work, paraffin wax (PW) was vacuum impregnated into poly(dimethylsiloxane) (PDMS)/boron nitride (BN)/polypyrrole (PPy) foam to create flexible phase change composites (PCCs) with excellent thermal conductivity and solar-thermal energy conversion efficiency. The PDMS/BN/PPy foams were successfully prepared via the sugar template and chemical vapor deposition methods. The PDMS/BN/PPy/PW PCCs exhibited excellent phase change latent heat of 172 J g and dimensional retention ratio of 98.91%. The continuous BN network imparted the PCCs with enhanced thermal conductivity of 0.43 W m K. Meanwhile, the flexible PCCs were capable of being elastically deformed and closely adhered to the rough surface, thus further improving the heat transfer efficiency. More importantly, the wrinkled PPy and the hierarchical porous structure improved light absorption by extending the optical path for multiple reflections, maintaining an outstanding solar-thermal energy conversion efficiency of 91.9%. A solar-thermal-electric energy conversion (STEEC) system was constructed to display the potential of PCCs to generate clean energy. PCCs could output a current of 84.7 mA and support the rotation of a fan for 243 s, even without light irradiation. This study provides a facile approach to preparing multi-functional PCCs, showing the advantages in the rapid collection and storage of solar energy.

中文翻译：

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基于分层多孔聚吡咯支架的柔性相变复合材料，用于宽带太阳能吸收和高效的太阳能-热-电能转换

具有储热性能的相变材料（PCM）在太阳能热能转换和利用系统中至关重要。然而，低热导率、低光吸收和严重脆性是主要的应用障碍因素。在这项工作中，石蜡（PW）被真空浸渍到聚（二甲基硅氧烷）（PDMS）/氮化硼（BN）/聚吡咯（PPy）泡沫中，以形成具有优异导热性和太阳热能的柔性相变复合材料（PCC）转换效率。通过糖模板和化学气相沉积方法成功制备了PDMS/BN/PPy泡沫。 PDMS/BN/PPy/PW PCC 表现出优异的相变潜热（172 J g）和尺寸保留率为 98.91%。连续的BN网络使PCCs的导热系数提高到0.43 W m K。同时，柔性PCCs能够弹性变形并紧密粘附在粗糙表面上，从而进一步提高传热效率。更重要的是，褶皱PPy和分级多孔结构通过延长多次反射的光路来提高光吸收，保持出色的91.9%的光热转换效率。建造了太阳能-热-电能量转换（STEEC）系统，以展示 PCC 产生清洁能源的潜力。即使没有光照射，PCC 也可以输出 84.7 mA 的电流，并支持风扇旋转 243 秒。这项研究提供了一种制备多功能PCC的简便方法，显示了太阳能快速收集和存储的优势。