X-ray Absorption Spectroscopy Characterization of a Li/S Cell

Yifan Ye; Ayako Kawase; Min-Kyu Song; Bingmei Feng; Yi-Sheng Liu; Matthew A Marcus; Jun Feng; Elton J Cairns; Jinghua Guo; Junfa Zhu

doi:10.3390/nano6010014

X-ray Absorption Spectroscopy Characterization of a Li/S Cell

Nanomaterials (Basel). 2016 Jan 11;6(1):14. doi: 10.3390/nano6010014.

Authors

Yifan Ye^{1

2}, Ayako Kawase^{3

4}, Min-Kyu Song⁵, Bingmei Feng^{6

7}, Yi-Sheng Liu⁸, Matthew A Marcus⁹, Jun Feng¹⁰, Elton J Cairns^{11

12}, Jinghua Guo^{13

14}, Junfa Zhu¹⁵

Affiliations

¹ National Synchrotron Radiation Laboratory and Collaborative Innovation Center of Suzhou Nano Science and Technology, University of Science and Technology of China, Hefei 230029, China. yifanye@lbl.gov.
² Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA. yifanye@lbl.gov.
³ Environmental Energy Technologies Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA. akawase@lbl.gov.
⁴ Department of Chemical and Biomolecular Engineering, University of California, Berkeley, CA 94720, USA. akawase@lbl.gov.
⁵ School of Mechanical and Materials Engineering, Washington State University, Pullman, WA 99164, USA. mksong325@gmail.com.
⁶ Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA. bfeng@lbl.gov.
⁷ School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001, China. bfeng@lbl.gov.
⁸ Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA. ysliu2@lbl.gov.
⁹ Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA. mamarcus@lbl.gov.
¹⁰ Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA. fjun@lbl.gov.
¹¹ Environmental Energy Technologies Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA. ejcairns@lbl.gov.
¹² Department of Chemical and Biomolecular Engineering, University of California, Berkeley, CA 94720, USA. ejcairns@lbl.gov.
¹³ Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA. jguo@lbl.gov.
¹⁴ Department of Chemistry and Biochemistry, University of California, Santa Cruz, CA 95064, USA. jguo@lbl.gov.
¹⁵ National Synchrotron Radiation Laboratory and Collaborative Innovation Center of Suzhou Nano Science and Technology, University of Science and Technology of China, Hefei 230029, China. jfzhu@ustc.edu.cn.

Abstract

The X-ray absorption spectroscopy technique has been applied to study different stages of the lithium/sulfur (Li/S) cell life cycle. We have investigated how speciation of S in Li/S cathodes changes upon the introduction of CTAB (cetyltrimethylammonium bromide, CH₃(CH₂)₁₅N⁺(CH₃)₃Br^-) and with charge/discharge cycling. The introduction of CTAB changes the synthesis reaction pathway dramatically due to the interaction of CTAB with the terminal S atoms of the polysulfide ions in the Na₂S_x solution. For the cycled Li/S cell, the loss of electrochemically active sulfur and the accumulation of a compact blocking insulating layer of unexpected sulfur reaction products on the cathode surface during the charge/discharge processes make the capacity decay. A modified coin cell and a vacuum-compatible three-electrode electro-chemical cell have been introduced for further in-situ/in-operando studies.

Keywords: X-ray absorption spectroscopy; capacity decay; cetyltrimethylammonium bromide; cycled cathode materials; in-situ/in-operando; insulating layer; lithium/sulfur cell; synthesis.