Volume 7, Issue 12 1900111
Full Paper

Nonuniform Redistribution of Sulfur and Lithium upon Cycling: Probing the Origin of Capacity Fading in Lithium–Sulfur Pouch Cells

Long Kong

Long Kong

Beijing Key Laboratory of Green Chemical Reaction Engineering and Technology, Department of Chemical Engineering, Tsinghua University, Beijing, 100084 P. R. China

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Qi Jin

Qi Jin

Beijing Key Laboratory of Green Chemical Reaction Engineering and Technology, Department of Chemical Engineering, Tsinghua University, Beijing, 100084 P. R. China

Key Laboratory for Photonic and Electronic Bandgap Materials, Ministry of Education, School of Physics and Electronic Engineering, Harbin Normal University, Harbin, 150025 Heilongjiang, China

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Jia-Qi Huang

Corresponding Author

Jia-Qi Huang

Advanced Research Institute of Multidisciplinary Science, Beijing Institute of Technology, Beijing, 100081 China

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Li-Da Zhao

Li-Da Zhao

Beijing Key Laboratory of Green Chemical Reaction Engineering and Technology, Department of Chemical Engineering, Tsinghua University, Beijing, 100084 P. R. China

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Peng Li

Peng Li

Beijing Key Laboratory of Green Chemical Reaction Engineering and Technology, Department of Chemical Engineering, Tsinghua University, Beijing, 100084 P. R. China

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Bo-Quan Li

Bo-Quan Li

Beijing Key Laboratory of Green Chemical Reaction Engineering and Technology, Department of Chemical Engineering, Tsinghua University, Beijing, 100084 P. R. China

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Hong-Jie Peng

Corresponding Author

Hong-Jie Peng

Department of Chemical Engineering, Stanford University, Stanford, CA, 94305 USA

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Xitian Zhang

Xitian Zhang

Key Laboratory for Photonic and Electronic Bandgap Materials, Ministry of Education, School of Physics and Electronic Engineering, Harbin Normal University, Harbin, 150025 Heilongjiang, China

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Qiang Zhang

Corresponding Author

Qiang Zhang

Beijing Key Laboratory of Green Chemical Reaction Engineering and Technology, Department of Chemical Engineering, Tsinghua University, Beijing, 100084 P. R. China

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First published: 04 March 2019
Citations: 41

Abstract

Lithium–sulfur (Li–S) batteries have emerged as a promising candidate for the next-generation high-energy-density system for energy-demanding applications. Despite innovations in concepts and materials that significantly improve the electrochemical performance of coin cells, Li–S pouch cells have the disadvantages of short cycle life and inferior rate capability in comparison with coin cells. Bridging the fundamentals of Li–S chemistry to the hindrance on its practical application is of great importance for the development of Li–S batteries. Herein, the nonuniformity of the distribution of sulfur and lithium upon cycling is probed as one of the origins for the rapid capacity fading in a Li–S pouch cell. In particular, the nonuniform evolution of sulfur/lithium distribution impairs the discharge capacity of a low-voltage plateau. Lithium polysulfide intermediates produced on discharge tend to diffuse toward the bottom of a pouch cell, leading to agglomeration of sulfur and thus passivating the cathode. The migration of polysulfides also etches lithium away from the central region of the anode and induces nonuniform anode pulverization. Herein, the importance of a rational design of a pouch cell to mitigate the nonuniform redistribution of the active material toward stable Li–S pouch cells is highlighted.

Conflict of Interest

The authors declare no conflict of interest.

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