Debonding at the interface between active particles and PVDF binder in Li-ion batteries

Seungjun Lee, Jun Yang, Wei Lu

Research output: Contribution to journalArticlepeer-review

57 Scopus citations

Abstract

Mechanical failure in the electrode is one of major reasons for capacity fade. In this study we focus on inter-particle fracture, specifically the debonding at the interface between the graphite particle and binder. We integrate the electrochemical-mechanical model and the cohesive zone model to investigate the interfacial debonding during lithium intercalation. We found that the mechanism of fracture at the particle/binder interface is different from that inside a particle. The debonding at the interface is caused by the expansion of the particle that is closely related to the total amount of lithium intercalation, while the fracture inside a particle is caused by the gradient of lithium concentration. As a result, debonding at the interface is more likely to occur as the particle size and C-rate decrease, which is opposite to the trend of fracture inside a particle that is more likely to occur as the particle size and C-rate increase. This understanding of debonding mechanism can provide insight into capacity fade and guide the development of more robust electrodes.

Original languageEnglish
Pages (from-to)37-44
Number of pages8
JournalExtreme Mechanics Letters
Volume6
DOIs
StatePublished - 1 Mar 2016

Keywords

  • Battery
  • Debonding
  • Electrochemical-mechanical model

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