Electrical properties of new glasses based on the Li2S-SiS2 system

Improvement of large energy density systems such as lithium ion batteries requires an understanding of the electrode materials and identification of new electrolytes. For safety reasons, solid sate electrolytes are preferred. This study is based on past results on the Li2S-SiS2 system. AC impedance spectroscopy was used to determine the ionic conductivity of glasses where additions were made of sulfides and oxides of groups TVA, VA, VB or VIA to the base glass composition 60/40 Li2S-SiS2 (mol%). These additions improved the stability of these glasses, so much so that thick samples (> 2 mm) could be prepared by cooling without quenching. Addition of lithium halides further increased conductivity. Ionic conductivities > 2 x 10(-3) S/cm at room temperature were measured, amongst the largest reported in the glass literature for lithium electrolytes. The conductivity activation energy of these glasses will be reported. (C) 1999 Elsevier Science B.V. All rights reserved.