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Title: Enhanced Cycling Stability of Rechargeable Li-O2 Batteries Using High Concentration Electrolytes

The electrolyte stability against reactive reduced-oxygen species is crucial for the development of rechargeable Li-O2 batteries. In this work, we systematically investigated the effect of lithium salt concentration in 1,2-dimethoxyethane (DME)-based electrolytes on the cycling stability of Li-O2 batteries. Cells with high concentration electrolyte illustrate largely enhanced cycling stability under both the full discharge/charge (2.0-4.5 V vs. Li/Li+) and the capacity limited (at 1,000 mAh g-1) conditions. These cells also exhibit much less reaction-residual on the charged air electrode surface, and much less corrosion to the Li metal anode. The density functional theory calculations are conducted on the molecular orbital energies of the electrolyte components and the Gibbs activation barriers for superoxide radical anion to attack DME solvent and Li+-(DME)n solvates. In a highly concentrated electrolyte, all DME molecules have been coordinated with salt and the C-H bond scission of a DME molecule becomes more difficult. Therefore, the decomposition of highly concentrated electrolyte in a Li-O2 battery can be mitigated and both air-cathodes and Li-metal anodes exhibits much better reversibility. As a results, the cyclability of Li-O2 can be largely improved.
Authors:
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Publication Date:
OSTI Identifier:
1239475
Report Number(s):
PNNL-SA-112653
Journal ID: ISSN 1616-301X; 48877; 48379; VT1201000
DOE Contract Number:
AC05-76RL01830
Resource Type:
Journal Article
Resource Relation:
Journal Name: Advanced Functional Materials; Journal Volume: 26; Journal Issue: 4
Publisher:
Wiley
Research Org:
Pacific Northwest National Laboratory (PNNL), Richland, WA (US), Environmental Molecular Sciences Laboratory (EMSL)
Sponsoring Org:
USDOE
Country of Publication:
United States
Language:
English
Subject:
Li-O2 battery; high concentration electrolyte; stability, protection; lithium-metal, air-electrode; Environmental Molecular Sciences Laboratory