Energy Storage Science and Technology ›› 2018, Vol. 7 ›› Issue (4): 654-660.doi: 10.12028/j.issn.2095-4239.2018.0035

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Thermal properties of a modified MOF-stearic acid composite phase change materials

LI Dan1, CHENG Xiaomin1,2, LI Yuanyuan1   

  1. 1. School of Materials Science and Engineering, Wuhan University of Technology, Wuhan 430070, Hubei, China;
    2. School of Mechanical and Electrical Engineering, Huanggang Normal University, Huanggang 438000, Hubei, China
  • Received:2018-03-09 Revised:2018-03-22 Online:2018-07-01 Published:2018-04-24

Abstract: ZIF-67, a metal-organic framework (MOF), was grown on expanded graphite (EG) sheet by in-situ precipitation to obtain modified ZIF-67/EG, which, upon calcination, formed a hierarchical porous Co3O4/EG hybrid. By using a melting blending and vacuum adsorption methods, stearic acid (SA), SA/Co3O4/EG composite phase change material (PCM) was then prepared. The materials were characterized for their microstructure, phase, phase change enthalpy, phase change temperature and charging/discharging behavior. The influence of the microstructure of Co3O4/EG on the thermal properties of the SA/Co3O4/EG composite PCMs was analyzed. The results showed that the effect of Co3O4/EG on the phase transition temperature of SA/Co3O4/EG composite PCMs was small, and the phase transition temperature was independent of the amount of Co3O4/EG addition. However, the latent heat of the composites PCMs decreased with increasing Co3O4/EG content, consistent with the theoretical calculation. The Co3O4/EG hierarchical porous structure was shown to be able to prevent the agglomeration of Co3O4, providing a high specific surface area and pore volume adsorption of SA. The synergistic effect of the porous structure Co3O4 and high thermal conductivity of EG could increase the heat transfer of SA and improve the heat release rate.

Key words: stearic acid, Co3O4/EG, phase change materials

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