Kazunori Takada

New lithium ion conductors based on Li2S-SiS2 system

Abstract There is great interest in sulfide glasses because of their high lithium ion conductivity. We have synthesized a new lithium ion conductive solid electrolyte based on Li 2 S-SiS 2 glass with the composition: 0.03Li 3 PO 4 -0.59Li 2 S-0.38SiS 2 at ambient pressure by quenching in liquid nitrogen. Its conductivity at room temperature was 6.9×10 −4 S cm −1 . The stability of the glass towards electrochemical reduction was dramatically improved compared with SiS 2 -Li 2 S-LiI glass. The glass synthesized with Li 2 SO 4 instead of Li 3 PO 4 also indicated good conductivity and stability against electrochemical reduction.

Photo-rechargeable solid state battery

Photoelectrochemical reactions on a semiconductor electrode (P-I aSi/SiO x ) with a silver ion conductive solid electrolyte (Ag 6 I 4 WO 4 ) have been investigated and photo-sensitizing effect was observed. On the basis of this reaction, photo-battery was examined which had a capability of self-charging under the sun or fluorescence illuminations. The battery consist of two parts. One is a MIS-type photovoltaic part (ITO/P-I as aSi/SiO x /Ag), and another is its energy storage part (Ag x V 2 O 5 /Ag 6 WO 4 /Ag x− V 2 O 5 ). Behaviors of photo reactions and the electrochemical characteristics in this system are discussed

Lithium ion conductive solid electrolyte and process for synthesizing the same

A sulfide-based lithium ion conductive solid electrolyte having a high ion conductivity and a high decomposition voltage contains crosslinking oxygen ions and silicon ions combined with the crosslinking oxygen ions in a structure of ##STR1##

Rechargeable solid-state batteries with silver ion conductors

Abstract Electrochemical behaviors of silver vanadium bronzes (Ag x V 2 O 5 ) with silver ion conductor (Ag 6 I 4 WO 4 ) were investigated in 0.3≦ x ≦1.0. Coulometric titration curves of these bronzes indicated that δ-phase bronze was available as electrode materials in solid-state cells using silver ion conductors. Properties of the rechargeable solid-state battery system (Ag 0.7 V 2 O 5 /Ag 6 I 4 WO 4 / Ag 0.7 V 2 O 5 ) were examined, and this battery showed excellent reversibility, stability, and shelf life in open-air and at high temperature.