Fast-cooling Studies, The Peg-based Spe Conductivity Of The Conductive Mechanism

Recently, polymer electrolytes have attracted more and more attention because of their widely potential applications, such as high energy density battery, electrochromic displays and all solid gas senors.The method of calculating bulk resistance of solid polymer electrolyte based on PEG/LiClO4 was described in this thesis. The ionic conductivity of several polymer electrolytes was worked out under different cooling condition, and the several factors , such as cooled way, temperature and added salt, that have effects on ionic conductivity were researched and the conduction model of supercooled solid polymer electrolyte of PEG/LiClO4 was discussed through the Ac impedance and XRD.The samples of cooled differently electrolytes such as pure PEG, pure lithium perchlorate and PEG/LiClO4 complex polymer electrolyte were studied in the experiment. The results make sure that the ionic conductivity increased with cooling increasingly speed. The structure of polymer electrolyte cooled in drier and liquid azote were analysed respectively using a X-ray diffractometer, the crystallinity of them obtained with an approxiate calculating method.The factors affecting ionic conductivity of solid polymer electrolytes were researched in this paper, in particularly temperature and added salt species. The ionic conductivity of each electrolyte increases with increasing temperature. When the free volume is definite, the smaller of ionic semidiameter is easier to transport in the polymer electrolyte. In the case of lithium salt, the lower of lattice energy of lithium salt complexed with polymer has a higher relatively ionic conductivity at room temperature.The electrochemical stability of supercooling polymer electrolyte based on PEG/LiClO4 is studied by measuring the impedance spectra at a different storage time. The results indicated that the transition of crystalline phase to amorphous phase is very sluggish and the technique of supercooling may be used to make the transition come ture.The conduction model fitting supercooling solid polymer electrolyte PEG/LiClO4 is based on the Effective Medium Theory. The ionic conductivity of SPE containing congeries is denoted as:The calculated results indicated that the relation of ionic conduction as a function of crystallinity decucted by the conduction model is inosculated with the experimental results.