Electrochemical Redox Potential of Li₂SO₄ Investigated Using the Appropriate All-Solid-State Cell Configuration

Abstract

Understanding the electrochemical window of battery materials is essential for designing all-solid-state batteries with stable cycling characteristics. Solid electrolytes (SEs) with high ionic conductivity have been extensively studied by using both electrochemical experiments and computational methods. However, lithium-containing materials with low ionic conductivity have not received the same level of attention, despite their widespread use in all-solid-state batteries. In this study, we focused on Li 2 SO 4 , a material with low ionic conductivity used in all-solid-state batteries, and measured its redox potential using all-solid-state cells. Accurate determination of the potential window requires the use of a SE with an appropriate oxidation and reduction tolerance. For our experiments, we used an oxide SE to target Li 2 SO 4 , and the redox potential of Li 2 SO 4 was found to be consistent with the reported standard electrode potential. Notably, Li 2 SO 4 exhibit high oxidation resistance. These findings highlight the importance of studying the electrochemical window in the design of all-solid-state batteries.