Photo-to-thermal conversion and energy storage of polyethylene glycol/copper sulfide composite PCMs

In order to improve the energy storage performance of polyethylene glycol (PEG), copper sulfide (CuS) was introduced into PEG to endow the function of photo-to-thermal conversion. A series of novel PEG/CuS composite phase change materials (PCMs) were prepared by melt blending method with polyethylene pyrrolidone (PVP) employed as a stabilizer. Results of the dispersion stability experiment and 100 thermal cycles test showed that 2 wt% PVP can effectively improve the stability of PEG/PVP/CuS composite PCMs. And the CuS nanoparticles were uniformly dispersed in the PEG through physical action with the help of PVP. DSC results showed that the melting enthalpy of PEG/PVP/CuS composite PCM is as high as 171.8 J/g, 164.0 J/g, and 156.2 J/g when the content of CuS is 2 wt%, 6 wt%, and 10 wt%, respectively. Thermal cycling test and TGA results demonstrated that PEG/PVP/CuS composite PCMs have excellent reliability and stability. The photo-absorption property of PEG/PVP/CuS composite PCM increases to the range of 0.44-0.852, 0.938-1.533, 1.335-2.462 respectively within the addition of 2 wt%, 6 wt%, 10 wt% CuS in the radiation range of 300-900 nm. And the photo-tothermal conversion efficiency of PEG/PVP/CuS composite PCMs was tested up to 87.36%. Therefore, the prepared PEG/PVP/CuS composite PCMs show remarkable potential in solar thermal utilization applications.

Automated summary

By introducing copper sulfide into polyethylene glycol, researchers successfully prepared PEG/CuS composite phase change materials with excellent photo-to-thermal conversion function. Experimental results showed that adding 2 wt% PVP can improve the stability of the composite PCMs, while CuS nanoparticles are uniformly dispersed in the PEG. Thermal performance testing revealed that the composite PCM has excellent melting enthalpy, with a high photo-to-thermal conversion efficiency of up to 87.36%.