In Situ Conversion of Metal–Organic Frameworks into VO2–V3S4 Heterocatalyst Embedded Layered Porous Carbon as an “All‐in‐One” Host for Lithium–Sulfur Batteries

Although lithium–sulfur batteries exhibit a fivefold higher energy density than commercial lithium‐ion batteries, their volume expansion and insulating nature, and intrinsic polysulfide shuttle have hindered their practical application. An alternative sulfur host is necessary to realize porous, cond...

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Veröffentlicht in:Small (Weinheim an der Bergstrasse, Germany) Germany), 2020-11, Vol.16 (47), p.n/a
Hauptverfasser: Seo, Seung‐Deok, Yu, Seungho, Park, Sangbaek, Kim, Dong‐Wan
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Sprache:eng
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Zusammenfassung:Although lithium–sulfur batteries exhibit a fivefold higher energy density than commercial lithium‐ion batteries, their volume expansion and insulating nature, and intrinsic polysulfide shuttle have hindered their practical application. An alternative sulfur host is necessary to realize porous, conductive, and polar functions; however, there is a tradeoff among these three critical factors in material design. Here, the authors report a layered porous carbon (LPC) with VO2/V3S4 heterostructures using one‐step carbonization–sulfidation of metal–organic framework templates as a sulfur host that meets all the criteria. In situ conversion of V–O ions into V3S4 nuclei in the confined 2D space generated by dynamic formation of the LPC matrix creates {200}‐facet‐exposed V3S4 nanosheets decorated with tiny VO2 nanoparticles. The VO2/V3S4 @ LPC composite facilitates high sulfur loading (70 wt%), superior energy density (1022 mA h g−1 at 0.2 C, 100 cycles), and long‐term cyclability (665 mA h g−1 at 1 C, 1000 cycles). The enhanced Li–S chemistry is attributed to the synergistic heterocatalytic behavior of polar VO2 and conductive V3S4 in the soft porous LPC scaffold, which accelerates polysulfide adsorption, conversion, and charge‐transfer ability simultaneously. A new “all‐in‐one” cathodic sulfur host, VO2–V3S4 heterocatalyst embedded layered porous carbon is developed for cathodic S host of Li–S batteries. The unusual heterocatalyst with carbon nanostructures offer highly efficient adsorption and conversion ability for lithium polysulfide, which originates from the in situ formation of metal–organic‐framework chemistry.
ISSN:1613-6810
1613-6829
DOI:10.1002/smll.202004806