Polymeric solid electrolyte system composed of triglycidyl ether of glycerol (TGEG), diglycidyl ether of polyethylene glycol (DGEPEG)and LiClO_4 salt were synthesized. In this' system the electrolyte has a pecular...Polymeric solid electrolyte system composed of triglycidyl ether of glycerol (TGEG), diglycidyl ether of polyethylene glycol (DGEPEG)and LiClO_4 salt were synthesized. In this' system the electrolyte has a pecularity that not merely can the LiClO_4 provide ionic carriers, but also catalyze the crosslinking reaction without adding an usual curing agent. The effect of salt content and degree of crosslinking on the viscoelasticity and ionic conductivity were studied. Both WLF and VTF equations were used to treat the experimental data in order to elucidate the mechanism of ionic conduction. It was found that the ionic conductivity of the system is carded out through the segmental motion mechanism. However, the data must be treated with care. For example, in evaluating WLF parameters, the contribution concerned with ionic carrier generation with temperature to the conductivity must be differentiated from that concerned with segmental motion. Besides, the temperature range suitable to WLF equation must also be considered. For VTF equation, it might be inapplicable ff the temperature is too low and close to the glass transition temperature of the specimen. Further study is needed in order to have a quantitative information on the limitation of these equations.展开更多
To raise the room temperature ionic conductivity and improve the mechanical strength of a PEO-based polymer electrolyte, a noncrystalline two-component epoxy electrolyte system has been prepared. The diglycidyl ether ...To raise the room temperature ionic conductivity and improve the mechanical strength of a PEO-based polymer electrolyte, a noncrystalline two-component epoxy electrolyte system has been prepared. The diglycidyl ether of polyethylene glycols as precursors of the system were synthesized by a two-step process. The presumed structure of the product was characterized, by ^(13)C, ~1H NMR and IR spectroscopy. It was found that a side-reaction occurred between the secondary hydroxyl group of PEG-chlorohydrin and epichlorohydrin in some degree, resulting in a by- product containing—CH_2Cl side group. By selecting a characteristic signal, which is undistorted by the increase in the length of CH_2 CH_2—O segment, a ~1H NMR approach of determining the equivalent epoxy weight (EEW) was proposed. The method is valid to specimens even though the EEW is as high as 2,000. The examination of the specimens by DSC showed that epoxidation greatly depressed the crystallinity of the PEG's, whereas the T_g was raised.展开更多
In an attempt to prepare a polymeric solid electrolyte with both high ionic conductivity at ambient temperature and adequate mechanical strength, an ionic conducting IPN composed of bisphenol A epoxy resin/polyethylen...In an attempt to prepare a polymeric solid electrolyte with both high ionic conductivity at ambient temperature and adequate mechanical strength, an ionic conducting IPN composed of bisphenol A epoxy resin/polyethylene glycol containing LiClO_4 was synthesized. The dependence of conductivity was investigated as a function of salt content, composition and temperature. It has been revealed that a maximum of conductivity appeared when EO/Li=25, where EO denotes the—(CH_2CH_2O)-unit in polyethylene glycol, and that the temperature dependence of conductivity followed VTF equation, suggesting that the motion of ionic carriers resulted from the segmental motion of the polymer. When glycerol epoxy resin was used instead of bisphenol A epoxy, the ambient temperature (25℃) conductivity could somewhat further be raised up to 3×10^(-5) S/cm.展开更多
基金The project supported by National Natural Science Foundation of China.
文摘Polymeric solid electrolyte system composed of triglycidyl ether of glycerol (TGEG), diglycidyl ether of polyethylene glycol (DGEPEG)and LiClO_4 salt were synthesized. In this' system the electrolyte has a pecularity that not merely can the LiClO_4 provide ionic carriers, but also catalyze the crosslinking reaction without adding an usual curing agent. The effect of salt content and degree of crosslinking on the viscoelasticity and ionic conductivity were studied. Both WLF and VTF equations were used to treat the experimental data in order to elucidate the mechanism of ionic conduction. It was found that the ionic conductivity of the system is carded out through the segmental motion mechanism. However, the data must be treated with care. For example, in evaluating WLF parameters, the contribution concerned with ionic carrier generation with temperature to the conductivity must be differentiated from that concerned with segmental motion. Besides, the temperature range suitable to WLF equation must also be considered. For VTF equation, it might be inapplicable ff the temperature is too low and close to the glass transition temperature of the specimen. Further study is needed in order to have a quantitative information on the limitation of these equations.
基金The project supported by National Natural Science Foundation of China.
文摘To raise the room temperature ionic conductivity and improve the mechanical strength of a PEO-based polymer electrolyte, a noncrystalline two-component epoxy electrolyte system has been prepared. The diglycidyl ether of polyethylene glycols as precursors of the system were synthesized by a two-step process. The presumed structure of the product was characterized, by ^(13)C, ~1H NMR and IR spectroscopy. It was found that a side-reaction occurred between the secondary hydroxyl group of PEG-chlorohydrin and epichlorohydrin in some degree, resulting in a by- product containing—CH_2Cl side group. By selecting a characteristic signal, which is undistorted by the increase in the length of CH_2 CH_2—O segment, a ~1H NMR approach of determining the equivalent epoxy weight (EEW) was proposed. The method is valid to specimens even though the EEW is as high as 2,000. The examination of the specimens by DSC showed that epoxidation greatly depressed the crystallinity of the PEG's, whereas the T_g was raised.
基金The Project supported by National Natural Science Foundation of China.
文摘In an attempt to prepare a polymeric solid electrolyte with both high ionic conductivity at ambient temperature and adequate mechanical strength, an ionic conducting IPN composed of bisphenol A epoxy resin/polyethylene glycol containing LiClO_4 was synthesized. The dependence of conductivity was investigated as a function of salt content, composition and temperature. It has been revealed that a maximum of conductivity appeared when EO/Li=25, where EO denotes the—(CH_2CH_2O)-unit in polyethylene glycol, and that the temperature dependence of conductivity followed VTF equation, suggesting that the motion of ionic carriers resulted from the segmental motion of the polymer. When glycerol epoxy resin was used instead of bisphenol A epoxy, the ambient temperature (25℃) conductivity could somewhat further be raised up to 3×10^(-5) S/cm.
