Unveiling the microscopic origin of asymmetric phase transformations in (de)sodiated Sb2Se3 with in situ transmission electron microscopy

Yi Wu, Wen Luo, Peng Gao, Chongyang Zhu, Xiaobing Hu, Ke Qu, Jing Chen, Yuqiao Wang, Litao Sun*, Liqiang Mai, Feng Xu

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


Sodium-ion batteries (SIBs) have huge application potential in large-scale energy storage systems due to high abundance and low cost of sodium resource. Metal chalcogenides, which store Na ions by multiple reactions of intercalation, conversion, and alloying, are considered promising anode materials with high theoretical capacity but often suffer from fast capacity fading and underlying reason remains elusive due to the lack of a precise understanding of microscopic behaviors. Here, combined with in situ high-resolution transmission electron microscopy and consecutive electron diffraction, we tracked phase transformations during (de)sodiation of Sb2Se3 nanowires in real time and revealed multi-step reaction mechanisms. During sodiation, Sb2Se3 NWs firstly underwent the intercalation of Na ions and forming NaxSb2Se3 phase, following by the conversion reaction into Na2Se and Sb phases; afterwards, metallic Sb could further alloy with Na to form Na3Sb phase via sequential intermediate NaxSb phases. While during desodiation, despite the reversible dealloying of Na3Sb phase, the following deconversion of Na2Se and Sb phases back to Sb2Se3 phase was incomplete, which is deemed to be the key factor causing rapid capacity decay. Furthermore, we reveal that contact interfaces between NWs greatly affected the degree of deconversion reaction due to possibly changed electrode reaction kinetics. This work not only reports the first experimental visualization proof showing the effect of contact interfaces on phase transformations of electrode materials, but also affords new insights into capacity decay mechanisms and rational design of high-capacity SIBs.

Original languageEnglish (US)
Article number105299
JournalNano Energy
StatePublished - Nov 2020


  • Contact interfaces
  • In situ transmission electron microscopy
  • Ionic transport
  • SbSe nanowires
  • Sodium-ion battery

ASJC Scopus subject areas

  • Renewable Energy, Sustainability and the Environment
  • Materials Science(all)
  • Electrical and Electronic Engineering

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