Investigating the Origin of the Enhanced Sodium Storage Capacity of Transition Metal Sulfide Anodes in Ether-Based Electrolytes

Research output: Journal Publications and Reviews (RGC: 21, 22, 62)21_Publication in refereed journalpeer-review

8 Scopus Citations
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  • Xucai Yin
  • Shu Guo
  • Baoyu Sun
  • Libin Wu
  • Chunyu Du
  • Jiajun Wang
  • Gepin Yin
  • Hua Huo


Original languageEnglish
Article number2110017
Journal / PublicationAdvanced Functional Materials
Issue number22
Online published24 Feb 2022
Publication statusPublished - 25 May 2022
Externally publishedYes


Although ether-based electrolytes have gradually been identified as a vital factor to achieving the excellent electrochemical performance observed in transition metal sulfide (TMS) anodes in sodium-ion batteries (SIBs), there is still a lack of a fundamental understanding about the origin of the positive effect of ether-based electrolytes on TMS anodes. Herein, a microspherical CoS2 anode has been taken as a representative of TMS. It has been demonstrated that the sodiation process involves not only a traditional conversion reaction taking place between solid-state CoS2 and Na2S, but also a solid–liquid phase conversion process between active materials and soluble sodium polysulfide (Na2Sn, 2 < n < 8). More importantly, it is first revealed that the long-term stability and the reversibility of CoS2 anode are mainly due to the solid–liquid conversion behavior, which makes bulk CoS2 gradually develop into a stable porous structure with fast Na+ transport kinetics and small stress/strain during cycling. Consequently, the CoS2 electrode delivers remarkable long-cycle life with an ultrahigh capacity retention rate of 94.8% even after 1500 cycles at 2 A g−1 (only 2.13 mAh g−1 fading per 100 cycles) and high volumetric capacity of 949 mAh cm−3 at a high active material loading of 3.3 mg cm−2.

Research Area(s)

  • carbonate-based electrolytes, ether-based electrolytes, excellent electrochemical performance, porous structures, sodium-ion batteries, solid–liquid phase conversion reactions

Citation Format(s)