Surfactant modification of expanded graphite to fabricate composite glycine water-based phase change material for cold energy storage

To improve the compatibility between expanded graphite (EG) and glycine water-based phase change material (GWPCM), different concentrations of modified expanded graphite (MEG) were prepared by using surfactant of triton x-100 (TX-100) as a modifier. The adsorption capacity of EG and MEG was implemented in detail. Composite GWPCM by using MEG as a porous material was prepared. The thermophysical properties of the prepared MEG/GWPCM were evaluated. The results showed that MEG-0.15 exhibited the best compatibility with GWPCM, and the adsorption capacity increased to 82.87 %. When the addition amount of MEG was 16 wt%, the MEG/GWPCM possessed a suitable melting temperature (-5.75 °C) and a high latent heat (250.77 J/g). Notably, the thermal conductivity was 2.4523 W/(m·K), which was 4.08 folds of GWPCM. The prepared composite materials showed great potential in the low-temperature cold energy storage of photovoltaic refrigeration systems.