Understanding Sulfur Redox Mechanisms in Different Electrolytes for Room-Temperature Na–S Batteries

Autor: Hanwen Liu, Wei-Hong Lai, Qiuran Yang, Yaojie Lei, Can Wu, Nana Wang, Yun-Xiao Wang, Shu-Lei Chou, Hua Kun Liu, Shi Xue Dou
Jazyk: angličtina
Rok vydání: 2021
Předmět:
Zdroj: Nano-Micro Letters, Vol 13, Iss 1, Pp 1-14 (2021)
Druh dokumentu: article
ISSN: 2311-6706
2150-5551
DOI: 10.1007/s40820-021-00648-w
Popis: Abstract This work reports influence of two different electrolytes, carbonate ester and ether electrolytes, on the sulfur redox reactions in room-temperature Na–S batteries. Two sulfur cathodes with different S loading ratio and status are investigated. A sulfur-rich composite with most sulfur dispersed on the surface of a carbon host can realize a high loading ratio (72% S). In contrast, a confined sulfur sample can encapsulate S into the pores of the carbon host with a low loading ratio (44% S). In carbonate ester electrolyte, only the sulfur trapped in porous structures is active via ‘solid–solid’ behavior during cycling. The S cathode with high surface sulfur shows poor reversible capacity because of the severe side reactions between the surface polysulfides and the carbonate ester solvents. To improve the capacity of the sulfur-rich cathode, ether electrolyte with NaNO3 additive is explored to realize a ‘solid–liquid’ sulfur redox process and confine the shuttle effect of the dissolved polysulfides. As a result, the sulfur-rich cathode achieved high reversible capacity (483 mAh g−1), corresponding to a specific energy of 362 Wh kg−1 after 200 cycles, shedding light on the use of ether electrolyte for high-loading sulfur cathode.
Databáze: Directory of Open Access Journals
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