Abstract
Alkali metal sulfur redox chemistry offers promising potential for high-energy-density energy storage. Fundamental understanding of alkali metal sulfur redox reactions is the prerequisite for rational designs of electrode and electrolyte. Here, we revealed a strong impact of alkali metal cation (Li + , Na + , K + , and Rb + ) on polysulfide (PS) stability, redox reversibility, and solid product passivation. We employed operando UV-vis spectroscopy to show that strongly negatively charged short-chain PS (e.g., S 4 2- /S 3 2- ) is more stabilized in the electrolyte with larger cation (e.g., Rb + ) than that with the smaller cation (e.g., Li + ), which is attributed to a stronger cation-anion electrostatic interaction between Rb + and S 4 2- /S 3 2- owing to its weaker solvation energy. In contrast, Li + is much more strongly solvated by solvent and thus exhibits a weaker electrostatic interaction with S 4 2- /S 3 2- . The stabilization of short-chain PS in K + -, Rb + -sulfur cells promotes the reduction of long-chain PS to short-chain PS, leading to high discharge potential. However, it discourages the oxidation of short-chain PS to long-chain PS, leading to poor charge reversibility. Our work directly probes alkali metal-sulfur redox chemistry in operando and provides critical insights into alkali metal sulfur reaction mechanism.
| Original language | English |
|---|---|
| Pages (from-to) | 10740-10748 |
| Number of pages | 9 |
| Journal | Journal of the American Chemical Society |
| Volume | 140 |
| Issue number | 34 |
| DOIs | |
| Publication status | Published - 2018 Aug 29 |
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ASJC Scopus subject areas
- Catalysis
- Chemistry(all)
- Biochemistry
- Colloid and Surface Chemistry
Cite this
Cation-Directed Selective Polysulfide Stabilization in Alkali Metal-Sulfur Batteries. / Zou, Qingli; Liang, Zhuojian; Du, Guan Ying; Liu, Chi You; Li, Elise Y.; Lu, Yi Chun.
In: Journal of the American Chemical Society, Vol. 140, No. 34, 29.08.2018, p. 10740-10748.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Cation-Directed Selective Polysulfide Stabilization in Alkali Metal-Sulfur Batteries
AU - Zou, Qingli
AU - Liang, Zhuojian
AU - Du, Guan Ying
AU - Liu, Chi You
AU - Li, Elise Y.
AU - Lu, Yi Chun
PY - 2018/8/29
Y1 - 2018/8/29
N2 - Alkali metal sulfur redox chemistry offers promising potential for high-energy-density energy storage. Fundamental understanding of alkali metal sulfur redox reactions is the prerequisite for rational designs of electrode and electrolyte. Here, we revealed a strong impact of alkali metal cation (Li + , Na + , K + , and Rb + ) on polysulfide (PS) stability, redox reversibility, and solid product passivation. We employed operando UV-vis spectroscopy to show that strongly negatively charged short-chain PS (e.g., S 4 2- /S 3 2- ) is more stabilized in the electrolyte with larger cation (e.g., Rb + ) than that with the smaller cation (e.g., Li + ), which is attributed to a stronger cation-anion electrostatic interaction between Rb + and S 4 2- /S 3 2- owing to its weaker solvation energy. In contrast, Li + is much more strongly solvated by solvent and thus exhibits a weaker electrostatic interaction with S 4 2- /S 3 2- . The stabilization of short-chain PS in K + -, Rb + -sulfur cells promotes the reduction of long-chain PS to short-chain PS, leading to high discharge potential. However, it discourages the oxidation of short-chain PS to long-chain PS, leading to poor charge reversibility. Our work directly probes alkali metal-sulfur redox chemistry in operando and provides critical insights into alkali metal sulfur reaction mechanism.
AB - Alkali metal sulfur redox chemistry offers promising potential for high-energy-density energy storage. Fundamental understanding of alkali metal sulfur redox reactions is the prerequisite for rational designs of electrode and electrolyte. Here, we revealed a strong impact of alkali metal cation (Li + , Na + , K + , and Rb + ) on polysulfide (PS) stability, redox reversibility, and solid product passivation. We employed operando UV-vis spectroscopy to show that strongly negatively charged short-chain PS (e.g., S 4 2- /S 3 2- ) is more stabilized in the electrolyte with larger cation (e.g., Rb + ) than that with the smaller cation (e.g., Li + ), which is attributed to a stronger cation-anion electrostatic interaction between Rb + and S 4 2- /S 3 2- owing to its weaker solvation energy. In contrast, Li + is much more strongly solvated by solvent and thus exhibits a weaker electrostatic interaction with S 4 2- /S 3 2- . The stabilization of short-chain PS in K + -, Rb + -sulfur cells promotes the reduction of long-chain PS to short-chain PS, leading to high discharge potential. However, it discourages the oxidation of short-chain PS to long-chain PS, leading to poor charge reversibility. Our work directly probes alkali metal-sulfur redox chemistry in operando and provides critical insights into alkali metal sulfur reaction mechanism.
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U2 - 10.1021/jacs.8b04536
DO - 10.1021/jacs.8b04536
M3 - Article
VL - 140
SP - 10740
EP - 10748
JO - Journal of the American Chemical Society
JF - Journal of the American Chemical Society
SN - 0002-7863
IS - 34
ER -