Conducting Mechanism of a Gel-Type Polymer Electrolyt

摘要

It is very interesting to study conducting mechanism on the gel-type polymer electrolyt especially the temperature dependence of the ion fractions, such as free ions(α_i), ion pairs(α_p) and triple ions(α_t). Vincent and co-workers have studied the ion dissociation and association of both LiClO_4 and LiCF_3SO_3 salts in low molecular weight polyethylene glycol(PEG) using molal conductance methods, but no temperature dependence of the fractions of the dissociated or aggregated ions was reported. Through investigating the symmetric modes of anion in polypropylene glycol (PPG) complexed with NaCF_3SO_3 and LiClO_4 by Raman scattering method, Torell et al. reported that ion association increases with increasing temperature. Yang et al. also observed a similar trend of ion association with temperature. In a previous paper, we employed tetraethylene glycol(TEG) and polyethylene glycol-400(PEG400) as plasticizers to investigate the changing trend of the ion fractions with temperature. In this paper we selected a system, which consisted of LiCF_3SO_3 as the alkali metal salt, tetraethylene glycol dimethyl ether or tetraethylene glycol, polyethylene glycol 400, as the plasticizer to further investigate the effect of salt concentration, temperature and molecular weight on the variation of the ion fractions.