National Science Foundation New Glasses May Enable More Powerful and Safer Batteries Steve W. Martin, Iowa State University, DMR 0710564 • Li batteries have concerns in large applications such as transportation and load leveling due to safety and cost • New solid state batteries using glassy solid electrolytes may be more powerful and safer. • New studies of Mixed Glass Former (MGF) Solid Electrolytes at Iowa State are enabling transformative understanding of this new class of solid electrolytes. • In collaboration with the University of Dortmund in Germany, new NMR methods are being used to probe the Na + movement in these electrolytes at the atomic level. • These measurements are combined with macroscopic conductivity measurements at ISU, Fig. 1, to develop transformative understanding of why the Na + ion motion can be improved in some MGF glasses while in others it is decreased, bottom Fig. 1. Fig. 1. Fig. 2. 2.2 2.4 2.6 2.8 3.0 3.2 3.4 3.6 3.8 4.0 1 10 100 T 1 (m illiseco n d s) 1000 K /T T1 0.5N a 2 S + 0 .5 G eS 2 x = 0 200 150 100 50 0 T ( o C) 0.0 0.2 0.4 0.6 0.8 1.0 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 x DC ( cm ) -1 0.5N a 2 S + 0 .5 [xG eS 2 + (1-x)P S 5/2 ] 56 58 60 62 64 66 68 70 0.0 0.2 0.4 0.6 0.8 1.0 0.5N a 2 S + 0.5[xG eS 2 + (1 -x)P S 5/2 ] E 0 (kJ/m ol) 3.6 3.8 4.0 4.2 4.4 4.6 4.8 5.0 (kJ/m ol)