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Covalently Interlinked Graphene Sheets with Sulfur‐Chains Enable Superior Lithium–Sulfur Battery Cathodes at Full‐Mass Level
Author(s) -
Tantis Iosif,
Bakandritsos Aristides,
Zaoralová Dagmar,
Medveď Miroslav,
Jakubec Petr,
Havláková Jana,
Zbořil Radek,
Otyepka Michal
Publication year - 2021
Publication title -
advanced functional materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.069
H-Index - 322
eISSN - 1616-3028
pISSN - 1616-301X
DOI - 10.1002/adfm.202101326
Subject(s) - polysulfide , graphene , sulfur , materials science , cathode , covalent bond , lithium–sulfur battery , electrolyte , electrochemistry , carbon fibers , battery (electricity) , lithium (medication) , chemical engineering , nanotechnology , organic chemistry , chemistry , electrode , composite material , composite number , engineering , medicine , power (physics) , physics , quantum mechanics , endocrinology , metallurgy
Sulfur represents a low‑cost, sustainable, and high theoretical capacity cathode material for lithium–sulfur batteries, which can meet the growing demand in portable power sources, such as in electric vehicles and mobile information technologies. However, the shuttling effect of the formed lithium polysulfides, as well as their low conductivity, compromise the electrochemical performance of lithium–sulfur cells. To tackle this challenge, a so far unexplored cathode, composed of sulfur covalently bonded directly on graphene is developed. This is achieved by leveraging the nucleophilicity of polysulfide chains, which react readily with the electrophilic centers in fluorographene, as experimental and theoretical data unveil. The reaction leads to the formation of carbon–sulfur covalent bonds and a particularly high sulfur content of 80 mass%. Owing to these features, the developed cathode exhibits excellent performance with only 5 mass% of conductive carbon additive, delivering very high full‑cathode‑mass capacities and rate capability, combined with superior cycling stability. In combination with a fluorinated ether as electrolyte additive, the capacity persists at ≈700 mAh g −1 after 100 cycles at 0.1 C, and at ≈644 mAh g −1 after 250 cycles at 0.2 C, keeping ≈470 mAh g −1 even after 500 cycles.