A polyaniline + polyethylene oxide mixture as a composite polymer positive electrode in solid-state secondary batteries

Abstract

We present here a physico-chemical and electrochemical study of a polyaniline (PAni) + polyethylene oxide (PEO) mixture prepared from a codissolution of both polymers in 1-methyl-2-pyrrolidinone. SEM observations showed that the best homogeneity of the polymer material was obtained when PAni was protonated directly in solution. FT-IR spectroscopic experiments showed that the entanglement of the PEO and PAni chains hindered the return of the PEO chains to their more stable helical form. XPS analyses of the films surface gave a 40% doping of the aniline units by the anions of the salt Li[N(CF 3SO 2) 2]. High gravimetric capacities of the order of 200 A h kg −1 (related to the PAni mass in the mixture) were extracted during the charge/discharge of the polymer material in a PEO based solid electrolyte. The best performances were obtained for PEO proportions comprised between 30 and 60 wt.%. Moreover, good cycling stability was observed. The PAni + PEO material could be suitable for use as an electrode material in high cycle life electrochemical devices.