Ionic conductivity and morphology of semi-interpenetrating-type polymer electrolyte entrapping poly(siloxane-g-allyl cyanide)

Abstract

We prepared a semi-IPN (interpenetrating network)-type solid polymer electrolyte (SPE) using poly (ethylene glycol)dimethacrylate (PEGDMA) as a polymer matrix containing a monocomb-type poly(siloxane-g-allyl cyanide) and poly(ethylene glycol)dimethylether (PEGDME) for the lithium secondary battery. The poly(siloxane-g-allyl cyanide)s were prepared by a hydrosilation reaction of poly (methyl hydrosiloxane) with allyl cyanide and characterized by H-1 NMR and FTIR. The semi-IPN-type electrolyte was prepared by thermal curing, and conductivities of samples were measured by impedance spectroscopy using an indium tin oxide (ITO) electrode. The ionic conductivity of the semi-IPN-polymer electrolyte was about 1.05 X 10(-5) S cm(-1) with 60 wt % of the poly(siloxane-g-allyl cyanide) and 6.96 X 10(-4) S cm(-1) with 50 wt % of the PEGDME and 10 wt % of the poly(siloxane-g-allyl cyanide) at 30 degrees C. The SEM morphology of the cross section of the semi-IPN-polymer electrolyte film was changed from discontinuous network to continuous network as increasing the PEGDME content and decreasing the poly(siloxane-g-allyl cyanide) content. The mechanical stability was also enhanced when increasing the PEGDME content.