Two types of shape-stabilized phase change materials (PCMs) based on polyethylene glycol (PEG) and graphene oxide (GO) were prepared by two different methods, including a simple blending process and esterification reaction. The interactions between PEG and GO for the blending product (PEG/GO PCMs) is physical and weak, while for the grafting product (PEG-g-GO) is chemical and strong. In the PEG-g-GO composites, almost all PEG segments were restricted due to the strong chemical interactions and therefore no endothermic peak was observed in the DSC curve. As the interactions between PEG and GO in the PEG/GO composites is weak and physical, the phase change enthalpy of the PEG/GO composites is as much as 163 J/g when the PEG content is 90 wt%. The result indicates that the shape-stabilized PCMs with weak physical interactions are more proper for thermal energy storage than that with strong chemical interactions.

The effect of vinylene carbonate (VC) as electrolyte additive on the electrochemical performances of the Si/disordered carbon (Si/DC) composite electrode / liquid electrolyte interface was studied in this paper. The electrochemical performances of Si/disordered carbon (Si/DC) composite electrode were systematically investigated by constant current charge-discharge. Field scanning electron microscopy (FSEM) was used to observe the change of electrodes in morphology after given cycle numbers. Cyclic voltammetry and electrochemical impedance spectra (EIS) techniques were employed to understand the influences of different electrolytes on the formation of Solid electrolyte interface(SEI) layers. The electrochemical performances were drastically improved by the introduction of a few percent of VC additive. It was found that the SEI layer formed in VC-containing electrolyte has a better resists to the stress caused by large volume variations associated with lithiation and delithiation reactions. This study highlights the importance of the SEI which governs the electrochemical performances of Si/disordered carbon (Si/DC) composite electrode.

Shape-stabilized phase change material (PCM) composed of polyethylene glycol and silica hollow nanospheres was prepared by a vacuum impregnating method. Thermal properties of the composite PCM were investigated by various techniques. Lower phase change temperature and enthalpy of the composite PCM were observed. It is concluded that the phase change properties of the composite PCM are influenced by the adsorption confinement of the PEG segments from the porous structure of the silica hollow nanospheres.