Unraveling the Conversion Evolution on Solid‐State Na–SeS2 Battery via In Situ TEM. Issue 14 (23rd March 2022)

• Record Type: Journal Article
• Authors: Zhang, Ziqi; Wang, Zaifa; Zhang, Long; Liu, Di; Yu, Chuang; Yan, Xinlin; Xie, Jia; Huang, Jianyu
• Is Part Of: Advanced science. Volume 9:Issue 14(2022)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-03-23
• Subjects: composite cathode -- in situ TEM -- Na–S battery -- Se doping -- solid‐state batteries; Science -- Periodicals; 505
• DOI: 10.1002/advs.202200744
• Languages: English
• ISSNs: 2198-3844

Abstract

Abstract: All‐solid‐state (ASS) Na–S batteries are promising for a large‐scale energy‐storage system owing to numerous merits. However, the high conversion reaction barrier impedes their practical application. In this work, the basic mechanism on how Se catalyzes the conversion reaction in the Na–S batteries is unraveled. The sodiation/desodiation of Na–SeS2 nanobatteries are systematically evaluated via in situ transmission electron microscopy (in situ TEM) with a microheating device. The real‐time analyses reveal an amorphous Na–Se x S y intermediate phase appears during the direct conversion from SeS2 to Na2 S, and a reverse reaction succeeds at 100 °C with a prior formation of Se. The absence of polysulfides and a much lower desodiation temperature in contrast to Na–S nanobatteries demonstrate that the Se incorporation significantly lowers the conversion reaction barrier. According to these findings, the ASS SeS2 batteries using a Na3 SbS4 solid electrolyte (SE) are assembled using various SE:C ratios in the composite cathodes to investigate the effect of the ion and electron transport on the electrochemical properties, including the effective transport properties, MacMullin number, and the tortuosity factor. The obtained results in turn confirm the findings from the in situ TEM. These findings are applicable to optimize other S‐based active materials and improve their utilization. Abstract : Se incorporation lowers the energy barrier in a Na–S battery and thereby catalyzes the reversible conversion reaction. The real‐time transmission electron microscopy discovers an amorphous Na–Se x S y intermediate, promoting the transformation from SeS2 to Na2 S without the formation of polysulfides. The reverse desodiation accomplishes at a low temperature of 100 °C.