Highly Conductive Solid-State Polymer Electrolyte Membrane for High Temperature Operations Thein Kyu, University of Akron, DMR The highlights of the solid-state lithium ion polymer electrolyte membrane thus developed are: (1)Ease of fabrication via photopolymerization at room temperature without requiring any solvent (2)Flexible and stretchable including outstanding bendability and twistability without forming any creases, thereby affording design flexibility like cable wires or films with space saving attributes (3)Excellent ionic conductivity comparable to those of conventional liquid electrolytes in the range of superionic conductors (i.e., S/cm at room temperature) (4)Excellent thermal stability up to 140 o C, which is significantly improved relative to 80 o C of the current liquid electrolyte battery technology (5)Exhibits self-extinguishability and flame retardancy (6)Electrochemically stable against LiFePO 4 cathode and Li 4 Ti 5 O 12 anode in half-cell tests (7)Alleviate fire hazard and environmentally benign. T. Kyu and M. Echeverri, “Highly conductive, completely amorphous lithium ion polymer electrolyte membranes,” US Patent Application: Univ. of Akron; (2012), pending. M. Echeverri, C. Hamad, and T. Kyu, “Highly Conductive, Completely Amorphous Polymer Electrolyte Membranes Fabricated Through Photo-polymerization of Poly(ethylene glycol diacrylate) Containing Solid Plasticizer and Ionic Salt Mixtures,” Solid State Ionics, 254, 92–100 (2014) Fig. 1. Solid-state polymer electrolyte membrane (PEM) (20/40/40 PEGDA/SCN/LiTFSI), showing (a) very high ionic conductivity and reproducibility during heating and cooling cycles up to 150 o C and (b) electrochemical stability up to 4.3 volts against Li electrode E-4 1E Ionic conductivity (S/cm) 1000/T(K ) 1st heating 1st cooling 2nd heating Temperature(  C) Tc=36°C Tm=49°C

Broader Impact: All participating students received interdisciplinary research training covering polymer materials synthesis and characterization, physical chemistry, electrochemistry, battery engineering and design. Training: Ms. Cosset Hamad (freshman) received undergraduate research training in Fall 2013, Spring and Summer Mr. Camilo Piedrahita, University of Antioquia, Colombia, received undergraduate internship in Spring Mr. Jinwei Cao graduated with M.S. in Polymer Engineering in May 2014 and now advance to Ph. D. program at the University of Akron. Collaboration: Started collaboration with Professor Yu Zhu (Polymer Science, University of Akron) for development of vertically aligned carbon nanotube (CNT) anode and with Professors Tsukahara and Adachi, Kyoto Institute of Technology, on surface modification of CNT anodes by grafting poly(ethylene glycol) and poly(dimethyl siloxane) via anionic polymerization. Fig. 2: (a) Conventional liquid electrolyte battery showing combustion of a labtop versus (b) our solid-state polymer lithium ion membrane showing bendability, twistability, stretchability, thermal stability, self- extinguishability and flame retardant behavior. Highly Conductive Solid-State Polymer Electrolyte Membrane for High Temperature Operations Thein Kyu, University of Akron, DMR Click here to play the video and ↓↑ to stop/replay the video Click here to play the video