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Insight into the Interfacial Process and Mechanism in Lithium–Sulfur Batteries: An In Situ AFM Study
Author(s) -
Lang ShuangYan,
Shi Yang,
Guo YuGuo,
Wang Dong,
Wen Rui,
Wan LiJun
Publication year - 2016
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.201608730
Subject(s) - in situ , mechanism (biology) , lithium (medication) , materials science , atomic force microscopy , sulfur , nanotechnology , chemistry , metallurgy , physics , psychology , organic chemistry , quantum mechanics , psychiatry
Lithium–sulfur (Li–S) batteries are highly appealing for large‐scale energy storage. However, performance deterioration issues remain, which are highly related to interfacial properties. Herein, we present a direct visualization of the interfacial structure and dynamics of the Li–S discharge/charge processes at the nanoscale. In situ atomic force microscopy and ex situ spectroscopic methods directly distinguish the morphology and growth processes of insoluble products Li 2 S 2 and Li 2 S. The monitored interfacial dynamics show that Li 2 S 2 nanoparticle nuclei begin to grow at 2 V followed by a fast deposition of lamellar Li 2 S at 1.83 V on discharge. Upon charging, only Li 2 S depletes from the interface, leaving some Li 2 S 2 undissolved, which accumulates during cycling. The galvanostatic precipitation of Li 2 S 2 and/or Li 2 S is correlated to current rates and affects the specific capacity. These findings reveal a straightforward structure–reactivity correlation and performance fading mechanism in Li–S batteries.