The development of phase change materials (PCMs) with high energy storage density, enhanced photothermal conversion efficiency and good form-stability is essential for practical application in utilization of solar energy. Herein, novel PCM composites (CPPCMs) with extremely high energy storage density and superb solar-thermal conversion performance were fabricated by introducing n-octacosane into three-dimensional (3D) porous cellulose nanofibril (CNF)/polypyrrole (PPy) hybrid aerogels. Due to the strong encapsulation capability of CNF/PPy hybrid aerogels (CPAs), the synthesized PCM composites maintained perfect shape stability above the melting point of n-octacosane. Further investigation showed CPPCMs exhibited extremely high latent heat in the range of 239.4–258.4 J/g and high loading rate of n-octacosane (up to 96%). The melting/cooling cycling test and thermogravimetric analysis indicated the composite PCMs possessed excellent cyclic stability and thermal stability. Moreover, simulated sunlight test showed that the photothermal conversion efficiency of CPPCMs significantly improved with the increased content of polypyrrole in the PCM composites. In conclusion, the obtained PCM composites, which exhibited excellent shape stability, superior solar-heat conversion capability and extremely high energy storage density, showed considerable potential for practical utilization and storage of solar energy.

具有高能量存储密度，增强的光热转换效率和良好的形状稳定性的相变材料（PCM）的开发对于太阳能的实际应用至关重要。在此，通过将正辛烷烷烃引入三维（3D）多孔纤维素纳米原纤维（CNF）/聚吡咯（PPy）混合气凝胶中，制备了具有极高能量存储密度和出色的太阳热转换性能的新型PCM复合材料（CPPCM）。由于CNF / PPy混合气凝胶（CPA）的强大封装能力，合成的PCM复合材料在n-熔点以上时仍保持完美的形状稳定性。十八烷。进一步的研究表明，CPPCM具有239.4–258.4 J / g的极高潜热和正辛烷的高负载率（高达96％）。熔融/冷却循环试验和热重分析表明，复合材料PCM具有优异的循环稳定性和热稳定性。此外，模拟阳光测试表明，随着PCM复合材料中聚吡咯含量的增加，CPPCM的光热转化效率显着提高。总之，所获得的具有优异的形状稳定性，优异的太阳热转换能力和极高的储能密度的PCM复合材料显示了在太阳能的实际利用和储存方面的巨大潜力。