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Architecting Freestanding Sulfur Cathodes for Superior Room‐Temperature Na–S Batteries
Author(s) -
Yang Huiling,
Zhou Si,
Zhang BinWei,
Chu ShengQi,
Guo Haipeng,
Gu QinFen,
Liu Hanwen,
Lei Yaojie,
Konstantinov Konstantin,
Wang YunXiao,
Chou ShuLei,
Liu HuaKun,
Dou ShiXue
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.202102280
Subject(s) - materials science , sulfur , cathode , redox , polysulfide , catalysis , kinetics , nanotechnology , chemical engineering , chemistry , electrode , biochemistry , electrolyte , engineering , metallurgy , physics , quantum mechanics
Room‐temperature sodium–sulfur (RT Na–S) batteries have attracted extensive attention because of their low cost and high specific energy. RT Na–S batteries, however, usually suffer from sluggish reaction kinetics, low reversible capacity, and short lifespans. Herein, it is shown that chain‐mail catalysts, consisting of porous nitrogen doped carbon nanofibers (PCNFs) encapsulating Co nanoparticles (Co@PCNFs), can activate sulfur via electron engineering. The chain‐mail catalysts Co@PCNFs with a micrograde hierarchical structure as a freestanding sulfur cathode (Co@PCNFs/S) can provide space for high mass loading of sulfur and polysulfides. The electrons can rapidly transfer from chain‐mail catalysts to sulfur and polysulfides during discharge–charge processes, therefore boosting its conversion kinetics. As a result, this freestanding Co@PCNFs/S cathode achieves a high sulfur loading of 2.1 ± 0.2 mg cm −2 , delivering a high reversible capacity of 398 mA h g −1 at 0.5 C (1 C = 1675 mA g −1 ) over 600 cycles and superior rate capability of an average capacity of 240 mA h g −1 at 5 C. Experimental results, combined with density functional theory calculations, demonstrate that the Co@PCNFs/S can efficiently improve the conversion kinetics between the polysulfides and Na 2 S via transferring electrons from Co to them, thereby realizing efficient sulfur redox reactions.