Building better lithium-sulfur batteries: from LiNO3 to solid oxide catalyst.
Sci Rep
; 6: 33154, 2016 09 15.
Article
em En
| MEDLINE
| ID: mdl-27629986
ABSTRACT
Lithium nitrate (LiNO3) is known as an important electrolyte additive in lithium-sulfur (Li-S) batteries. The prevailing understanding is that LiNO3 reacts with metallic lithium anode to form a passivation layer which suppresses redox shuttles of lithium polysulfides, enabling good rechargeability of Li-S batteries. However, this view is seeing more challenges in the recent studies, and above all, the inability of inhibiting polysulfide reduction on Li anode. A closely related issue is the progressive reduction of LiNO3 on Li anode which elevates internal resistance of the cell and compromises its cycling stability. Herein, we systematically investigated the function of LiNO3 in redox-shuttle suppression, and propose the suppression as a result of catalyzed oxidation of polysulfides to sulfur by nitrate anions on or in the proximity of the electrode surface upon cell charging. This hypothesis is supported by both density functional theory calculations and the nitrate anions-suppressed self-discharge rate in Li-S cells. The catalytic mechanism is further validated by the use of ruthenium oxide (RuO2, a good oxygen evolution catalyst) on cathode, which equips the LiNO3-free cell with higher capacity and improved capacity retention over 400 cycles.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Idioma:
En
Revista:
Sci Rep
Ano de publicação:
2016
Tipo de documento:
Article
País de publicação:
ENGLAND
/
ESCOCIA
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GB
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GREAT BRITAIN
/
INGLATERRA
/
REINO UNIDO
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SCOTLAND
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UK
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UNITED KINGDOM