Shell-Protective Secondary Silicon Nanostructures as Pressure-Resistant High-Volumetric-Capacity Anodes for Lithium-Ion Batteries

Jiangyan Wang, Lei Liao, Yuzhang Li, Jie Zhao, Feifei Shi, Kai Yan, Allen Pei, Guangxu Chen, Guodong Li, Zhiyi Lu, Yi Cui

Research output: Contribution to journalArticlepeer-review

42 Scopus citations

Abstract

The nanostructure design of a prereserved hollow space to accommodate 300% volume change of silicon anodes has created exciting promises for high-energy batteries. However, challenges with weak mechanical stability during the calendering process of electrode fabrication and poor volumetric energy density remain to be solved. Here we fabricated a pressure-resistant silicon structure by designing a dense silicon shell coating on secondary micrometer particles, each consisting of many silicon nanoparticles. The silicon skin layer significantly improves mechanical stability, while the inner porous structure efficiently accommodates the volume expansion. Such a structure can resist a high pressure of over 100 MPa and is well-maintained after the calendering process, demonstrating a high volumetric capacity of 2041 mAh cm-3. In addition, the dense silicon shell decreases the surface area and thus increases the initial Coulombic efficiency. With further encapsulation with a graphene cage, which allows the silicon core to expand within the cage while retaining electrical contact, the silicon hollow structure exhibits a high initial Coulombic efficiency and fast rise of later Coulombic efficiencies to >99.5% and superior stability in a full-cell battery.

Original languageEnglish (US)
Pages (from-to)7060-7065
Number of pages6
JournalNano letters
Volume18
Issue number11
DOIs
StatePublished - Nov 14 2018

All Science Journal Classification (ASJC) codes

  • Bioengineering
  • Chemistry(all)
  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanical Engineering

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