多孔炭基定形相变储热材料的研究进展

A review of porous carbon-based shape-stabilized phase change materials for heat storage

储能技术可以解决能源供需在时空上不匹配的矛盾,从而提高能源利用效率。相变储热是一种极具潜力的储能技术,广泛应用于太阳能、节能建筑、工业余废热回收和热管理系统,其储热介质为相变材料,具有潜热大、相变温度恒定等优点,可实现储热与控温双重目的。固-液相变材料是研究较多的一类相变材料,具有储能密度高、相变温度可调、化学性质稳定、价格低廉等优点,但存在相变泄漏、热导率低等问题,一定程度上阻碍了其应用,将多孔材料引入固-液相变材料构筑定形相变材料可以解决上述问题。特别是,以多孔炭作为定形基体制备的定形相变材料机械强度增强,导热率显著提升,封装性和稳定性优良。对多孔炭基定形相变材料的研究进展进行了系统总结,分析了膨胀石墨、碳纳米管、石墨烯氧化物、生物炭等多孔碳材料的孔结构、表面改性、质量分数、分子间作用力等因素对定形相变材料定形能力、热性能和相变行为的影响,讨论了其他多孔碳基体如活性炭、泡沫炭、氮化碳制备的定形相变储热材料的性能,概述了多孔碳基定形相变材料的应用研究现状。最后,通过对比不同种类多孔碳基体制备的定形相变材料的主要性能及所呈现出的不同优势,提出应用时的材料选择建议,并对未来的研究方向进行了展望。

Energy storage technology can solve the contradiction between energy supply and demand in time and space and thus improve energy utilization efficiency.As a potential heat storage technology,phase change heat storage is widely used in solar energy,energy-saving buildings,industrial waste heat recovery and thermal management systems.Its heat storage medium is phase change materials(PCMs) which mainly include solid-solid PCMs and solid-liquid PCMs.The PCMs can achieve the dual purposes of heat storage and temperature control due to their large latent heat and constant phase change temperature.Solid-liquid PCMs are a kind of phase change materials that are widely studied.They have the advantages of high-energy storage density,adjustable phase change temperature,stable chemical properties and low price.However,the application of solid-liquid PCMs is hindered by liquid leakage during phase change,low thermal conductivity and phase separation.Those problems can be solved by introducing porous materials into solid-liquid PCMs.Particularly,the shape-stabilized PCMs prepared with porous carbon matrix exhibit enhanced mechanical strength,improved thermal conductivity,excellent encapsulation and stability.This review systematically summarizes the research progress of porous carbon-based shape-stabilized PCMs.The effects of the pore structure,surface modification,mass fraction and intermolecular force of expanded graphite,carbon nanotubes,graphene oxides and biological porous carbon on the shape-stabilized capacity,thermal performances and phase change behaviors of shape-stabilized PCMs are analyzed.Meanwhile,the performances of shape-stabilized PCMs prepared with other porous carbon matrices are discussed,such as active carbon,carbon foam and carbon nitride.The research status on the application of porous carbon-based shape-stabilized PCMs is also introduced.At last,by comparing the main performances and different advantages of shape-stabilized PCMs prepared with different porous carbon matrix,some suggestions for material selection in the application are put forward.Also,the future research topics are outlined.