Lithiation Pathway Mechanism of Si-C Composite Anode Revealed by the Role of Nanopore using in Situ Lithiation

Hyun Jeong Lee, Jong Seok Moon, Young Woon Byeon, Woo Young Yoon, Hong Kyu Kim, Jae Pyoung Ahn

Research output: Contribution to journalArticlepeer-review

1 Citation (Scopus)

Abstract

Lithiation kinetics of a Si-C composite anode for high-capacity lithium (Li)-ion batteries were investigated through in situ lithiation and electrochemical C-V measurements using a focused ion beam (FIB). Here, we found in the lithiation procedure that Li migrates sequentially into carbon (C), nanopores, and silicon (Si) in the Si-C composite. In the first lithiation step, Li was intercalated inside C particles while spreading over the surface of the C particles. The second lithiation process occurred through the filling of nanopores existing between electrode particles that consisted of the Si-C composite. The nanopores acted as a Li reservoir during the pore-filling process. Finally, the Si particles were lithiated with a volume expansion of ∼70%, corresponding to a 300% volume expansion of 25 wt % Si particles included in the composite anode. The nanopores did not accommodate a large volume expansion of Si particles, because pore-filling lithiation occurred before the Si lithiation in the charging process. We suggest a design rule related to the role of the nanopores of the Si-C composite anode in LIB systems.

Original languageEnglish
Pages (from-to)2469-2476
Number of pages8
JournalACS Energy Letters
Volume7
Issue number8
DOIs
Publication statusPublished - 2022 Aug 12

ASJC Scopus subject areas

  • Chemistry (miscellaneous)
  • Renewable Energy, Sustainability and the Environment
  • Fuel Technology
  • Energy Engineering and Power Technology
  • Materials Chemistry

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