Conductivity of Electronic and Ionic Conducting Block Copolymer Electrolytes through Electrochemical Doping in the Solid-State

A battery electrode requires the transport of electronic and ionic charges to an active material in the nanometer length scale for redox reactions to occur. The traditional battery electrode design consists of an active material mixed with carbon black (electronic conduction), and an insulating binder material, which is then backfilled with liquid electrolyte. It’s a beneficial to design a binder material that can conduct both electronic and ionic charges in the nanometer length scale, thus eliminating the need for carbon black and liquid electrolyte). We use poly(3-hexylthiophene)-block-poly(ethylene-oxide) (P3HT-b-PEO) as an electronic and ionic conducting polymer, which self assembles in the 20-30 nanometer length scale. 2 The P3HT phase conducts electronic charge while the PEO phase conducts ionic charges. The application of this material in a lithium battery with LiFePO4 active material showed specific capacity that approaches theoretical capacity and has minimal capacity fade.