Expanded graphite for thermal conductivity and reliability enhancement and supercooling decrease of MgCl2⋅6H2O phase change material

• Published in: Materials research bulletin 2018-06, Vol.102, p.203-208
• Main Authors: Song, Zichen, Deng, Yong, Li, Jinhong, Nian, Hongen
• Format: Article
• Language: English
• Subjects: A. Composites; B. Phase transitions; C. Differential scanning calorimetry (DSC); CALORIMETRY; D. Energy storage; E. Thermal conductivity; ENCAPSULATION; ENERGY STORAGE; GRAPHITE; HEAT TRANSFER; MAGNESIUM CHLORIDES; MATERIALS SCIENCE; PHASE CHANGE MATERIALS; POROUS MATERIALS; STRONTIUM CARBONATES; SUPERCOOLING; THERMAL CONDUCTIVITY; WATER
• ISSN: 0025-5408; 1873-4227
• DOI: 10.1016/j.materresbull.2018.02.024

[Display omitted] •MgCl2·6H2O/EG composite PCMs show the superior thermal transfer ability.•83.33 wt.% of MgCl2·6H2O encapsulated in composite PCM was obtained.•EG and nucleating agents decreased the supercooling degree. Expanded graphite (EG) is considered as a promising supporter for phase change material (PCM) due to its unique porous structure and excellent heat transfer ability. In the study, EG with different mass fractions (9 wt.%, 13 wt.%, 16.67 wt.%, and 20 wt.%) was respectively blended with MgCl2·6H2O. The thermal conductivity data of composite PCMs with 9 wt.%, 13 wt.%, 16.67 wt.%, and 20 wt.% of EG was respectively measured to be 0.942 W/m K, 1.053 W/m K, 1.354 W/m K and 1.658 W/m K. DSC analysis showed that 16.67 wt.% of EG decreased the degree of supercooling by 29.4 °C and that the addition of 3.0 wt.% SrCO3 further decreased the degree of supercooling by 17.9 °C. The maximum encapsulation weight percentage of MgCl2·6H2O reached 83.33 wt.% after 30 phase change cycles without significantly reducing its latent heat value, exhibiting the relatively stable thermal reliability.