期刊
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
卷 117, 期 26, 页码 14712-14720出版社
NATL ACAD SCIENCES
DOI: 10.1073/pnas.2006301117
关键词
lithium sulfur batteries; lean electrolyte; chemical bonding; carbon; oxygen
资金
- US Department of Energy (DOE) [DEEE0008202, DEEE0008200]
- Maryland NanoCenter and its AIMLab
- Vehicle Technology Office of the United States through the Advanced Battery Materials Research Program [DE-SC0012704]
- US DOE Office of Science [DE-SC0012704]
Lithium sulfur batteries (LSBs) are promising next-generation rechargeable batteries due to the high gravimetric energy, low cost, abundance, nontoxicity, and high sustainability of sulfur. However, the dissolution of high-order polysulfide in electrolytes and low Coulombic efficiency of Li anode require excess electrolytes and Li metal, which significantly reduce the energy density of LSBs. Quasi-solid-state LSBs, where sulfur is encapsulated in the micropores of carbon matrix and sealed by solid electrolyte interphase, can operate under lean electrolyte conditions, but a low sulfur loading in carbon matrix (<40 wt %) and low sulfur unitization (<70%) still limit the energy density in a cell level. Here, we significantly increase the sulfur loading in carbon to 60 wt % and sulfur utilization to similar to 87% by dispersing sulfur in an oxygen-rich dense carbon host at a molecular level through strong chemical interactions of C-S and O-S. In an all-fluorinated organic lean electrolyte, the C/S cathode experiences a solid-state lithiation/delithiation reaction after the formation of solid electrolyte interphase in the first deep lithiation, completely avoiding the shuttle reaction. The chemically stabilized C/S composite retains a high reversible capacity of 541 mAh center dot g(-1) (based on the total weight of the C/S composite) for 200 cycles under lean electrolyte conditions, corresponding to a high energy density of 974 Wh center dot kg(-1). The superior electrochemical performance of the chemical bonding-stabilized C/S composite renders it a promising cathode material for highenergy and long-cycle-life LSBs.
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