Polyacrylonitrile–propylene carbonate–CuX2 (X=Cl, Br, CF3SO3) solid polymer electrolyte

A series of poly(acrylonitrile)–propylene carbonate–CuX2 (PAN–PC–CuX2, where X=Cl, Br and CF3SO3) foils of thickness between 0.03 and 0.09 cm, were prepared by means of the solution cast technique. The PAN–PC–CuX2 system forms flexible foils of good mechanical properties even at high solvent and salt contents. Conductivities of the foils obtained from the analysis of impedance spectra, reach the level of ca. 5×10−3 Ω−1 cm−1. The temperature variation of the conductivity for all the systems studied is of the Arrhenius type. The cyclic polarisation (within the −1 V to +1 V range) of the Pt|electrolyte|Pt and Cu|electrolyte|Cu cells shows that the deposition of copper from the electrolyte is basically feasible and reversible. The Cu2++2e−⇌Cu redox process, which takes place in the presence of the weak ligand CF3SO−3, [PAN–PC–Cu(CF3SO3)2 system] is approximately two orders of magnitude slower than the CuX2−nn+2e−⇌Cu+nX− reaction (X=Cl and Br) which occurs in the case of the PAN–PC–CuCl2 and PAN–PC–CuBr2 electrolytes.