Enhanced Electrochemical Stability and Moisture Reactivity of Al2S3 Doped Argyrodite Solid Electrolyte. Issue 7 (6th July 2021)

• Record Type: Journal Article
• Authors: Min, Sanghyuk; Park, Chanhwi; Yoon, Insang; Kim, Gideok; Seol, Kwonsoo; Kim, Taeseung; Shin, Dongwook
• Is Part Of: Journal of the Electrochemical Society. Volume 168:Issue 7(2021)
• Publication Date: 2021-07-06
• Subjects: Electrochemistry -- Periodicals; 541.3705
• DOI: 10.1149/1945-7111/ac0f5c
• Languages: English
• ISSNs: 0013-4651

Abstract

Abstract : All-solid-state lithium-ion batteries are considered a promising next-generation lithium-ion batteries for their safety and high energy density. Among solid electrolytes, sulfide-based solid electrolytes have received attention from academia for their good contact properties such as mechanical deformability and high ionic conductivity. Specifically, argyrodite, which has Li6 PS5 X (X = Cl, Br, I) structure, shows a high lithium ionic conductivity (>10 −3 S cm −1 ) at room temperature. However, sulfide-based solid electrolytes are chemically unstable in reaction to lithium metal and moisture because of the high reactivity of sulfur. Also, sulfide-based solid electrolytes react with active materials on the interface in composite cathodes. Moreover, this insufficient electrochemical stability of sulfide-based solid electrolytes can deteriorate the cell performance such as discharge capacity in prolonged cycles. We investigated the effects of partial substitution of Al2 S3 for P2 S5 to form the Al-S bonding instead of the P-S bonding in the PS4 3− main unit of the Li6 PS5 X structure. The Al-S bonding is electrochemically more stable than the P-S bonding due to a larger electronegativity difference between the two atoms. We show that the Al2 S3 substitution in an argyrodite structure used for the composite cathode significantly improves the electrochemical stability.