Electrolytically formed batteries (EFBs) form their positive and negative electrode in-situ upon the application of potential. During the cathode development in a LiI based EFB, the oxidized iodide ions formed during polarization coordinate with a polymer additive such as poly (vinyl-pyrrolidone) to form an electronically and ionically conductive polyiodide composite. A comprehensive study of the electronic and ion transport of these composites is presented here relative to polyiodide structure for various compositions of anhydrous and hydrated LiI-I(2) vs. PVP. (C) 2011 Elsevier B.V. All rights reserved.