A research team headed by Prof. Quan Shi from the Dalian Institute of Chemical Physics (DICP) of the Chinese Academy of Sciences (CAS) has suggested a novel concept of “Spatiotemporal Phase Change Materials” (STPCMs) long-term storage and controllable release of thermal energy depending on phase change materials (PCMs).
Schematic diagram of the Spatiotemporal PCMs. Image Credits: DENG Chengxin
Journal of Energy Chemistry published this research on February 16th, 2023.
PCMs are promising in the field of temperature control and thermal energy storage. But, PCMs generally expel their stored latent heat instinctively as the temperature below the phase transition temperature, which renders release uncontrollable and thermal energy storage and thus hampers their practical application.
The scientists developed erythritol/sodium carboxymethylcellulose/tetrasodium ethylenediaminetetraacetate (ERY/CMC/EDTA-4Na) composite PCMs with novel spatiotemporal thermal energy storage characteristics to overcome this problem. They were characterized as spatiotemporal PCMs (STPCMs) and displayed the ability of controllable release of thermal energy and long-term storage.
They discovered that the composite PCMs were not able to lose latent heat owing to spontaneous crystallization at the time of cooling; however, they could controllably expel thermal energy via cold crystallization at the time of reheating.
Their cold-crystallization temperature and enthalpy could be adjusted by proportional addition of EDTA-4Na to the composite.
Prof. Quan Shi, Dalian Institute of Chemical Physics, Chinese Academy of Sciences
When the mass fractions of EDTA-4Na and CMC were both 10%, the composite PCMs exhibited an optical cold-crystallization temperature of 51.7 °C and enthalpy of 178.1 J/g. For up to over two months, the supercooled composite PCMs with no latent heat release upheld at room temperature (10–25 °C), and consequently the stored latent heat was controllably expelled through heterogeneous nucleation or thermal triggering.
Journal Reference:
Li, Y., et al. (2023). Spatiotemporal phase change materials for thermal energy long-term storage and controllable release. Journal of Energy Chemistry. doi.org/10.1016/j.jechem.2023.01.052.