Operando soft X-ray absorption spectroscopic study on microporous carbon-supported sulfur cathodes. Issue 65 (2nd November 2020)

• Record Type: Journal Article
• Authors: Xiao, Yao; Yamamoto, Kentaro; Matsui, Yukiko; Watanabe, Toshiki; Nakanishi, Koji; Uchiyama, Tomoki; Shingubara, Shoso; Ishikawa, Masashi; Watanabe, Masayoshi; Uchimoto, Yoshiharu
• Is Part Of: RSC advances. Volume 10:Issue 65(2020)
• Page Start: 39875
• Page End: 39880
• Publication Date: 2020-11-02
• Subjects: Chemistry -- Periodicals; 540.5
• DOI: 10.1039/d0ra08299f
• Languages: English
• ISSNs: 2046-2069

Abstract

Abstract : The reaction mechanism of the sulfur cathode in the microporous carbon during discharge was observed by operando XAS. Abstract : Sulfur is a promising material for next-generation cathodes, owing to its high energy and low cost. However, sulfur cathodes have the disadvantage of serious cyclability issues due to the dissolution of polysulfides that form as intermediate products during discharge/charge cycling. Filling sulfur into the micropores of porous carbon is an effective method to suppress its dissolution. Although microporous carbon-supported sulfur cathodes show an electrochemical behavior different from that of the conventional sulfur ones, the corresponding reaction mechanism is not clearly understood. In this study, we focused on clarifying the reaction mechanism of microporous carbon-supported sulfur cathodes by operando soft X-ray absorption spectroscopy. In the microporous carbon support, sulfur was present as smaller fragments compared to conventional sulfur. During the first discharge process, the sulfur species in the microporous carbon were initially reduced to S6 2− and S2 2− and then to Li2 S. The S6 2− and S2 2− species were observed first, with S2 2− being the main polysulfide species during the discharge process, while Li2 S was produced in the final discharge process. The narrow pores of microporous carbon prevent the dissolution of polysulfides and influence the reaction mechanism of sulfur cathodes.