Structure and charge transport of polyiodide networks for electrolytically in-situ formed batteries

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–I2 vs. PVP.

► Mixed conducting polyiodides formed spontaneously by mixing iodine and PVP.
► Polyiodide species provide dual conductivity for electrolytically formed cathode.
► Saturation of polymer with polyiodide occurs at peak electronic conductivity value.