A room-temperature sodium-sulfur battery with high capacity and stable cycling performance.
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ABSTRACT: High-temperature sodium-sulfur batteries operating at 300-350?°C have been commercially applied for large-scale energy storage and conversion. However, the safety concerns greatly inhibit their widespread adoption. Herein, we report a room-temperature sodium-sulfur battery with high electrochemical performances and enhanced safety by employing a "cocktail optimized" electrolyte system, containing propylene carbonate and fluoroethylene carbonate as co-solvents, highly concentrated sodium salt, and indium triiodide as an additive. As verified by first-principle calculation and experimental characterization, the fluoroethylene carbonate solvent and high salt concentration not only dramatically reduce the solubility of sodium polysulfides, but also construct a robust solid-electrolyte interface on the sodium anode upon cycling. Indium triiodide as redox mediator simultaneously increases the kinetic transformation of sodium sulfide on the cathode and forms a passivating indium layer on the anode to prevent it from polysulfide corrosion. The as-developed sodium-sulfur batteries deliver high capacity and long cycling stability.
SUBMITTER: Xu X
PROVIDER: S-EPMC6155237 | biostudies-literature | 2018 Sep
REPOSITORIES: biostudies-literature
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