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In Situ EQCM Study Examining Irreversible Changes the Sulfur–Carbon Cathode in Lithium–Sulfur Batteries

Author:
Wu, Heng-Liang, Huff, Laura A., Esbenshade, Jennifer L., Gewirth, Andrew A.
Source:
ACS Applied Materials & Interfaces 2015 v.7 no.37 pp. 20820-20828
ISSN:
1944-8252
Subject:
batteries, cathodes, roughness
Abstract:
In situ EQCM experiments were used to investigate the stability and roughness changes occurring in a sulfur–carbon cathode utilized for a Li–S battery during the charge–discharge process. Results show that the sulfur–carbon cathode gains mass during the first discharge plateau (∼2.4 V) due to the formation of the long chain polysulfides during the discharge (lithiation) process. However, further discharge to below 2.4 V yields an increase in the crystal resistance (Rc) suggesting the sulfur–carbon cathode becomes rougher. During the charge (delithiation) process, the roughness of the sulfur–carbon cathode decreases. Time dependent measurements show that the electrode surface becomes rougher with the deeper discharge, with the change occurring following a step to 1.5 V. The sulfur–carbon cathode exhibits stable Rc and frequency behavior initially, but then becomes rougher in subsequent following cycles.
Agid:
5284241