Polydopamine coated Si nanoparticles allow for improved mechanical and electrochemical stability

Utkarsh Ahuja, Bo Wang, Pu Hu, Julien Rethore, Katerina E. Aifantis

Research output: Contribution to journalArticlepeer-review

1 Scopus citations

Abstract

Numerous experiments suggest that the capacity decay of Silicon (Si) porous electrodes is related to the significant fracture experienced during the lithiation/de-lithiation process. In this work, modeling and surface engineering of nanosized Si is employed to synthesize nanocomposites with enhanced mechanical and electrochemical stability. Initially, a multiphysics model is applied to predict the size of Si particles that limit damage formation. The model is experimentally verified against scanning electron microscopy (SEM), which shows the fracture of Si microparticles after the first and second cycles. Particles less than 100 nm are predicted to be mechanically stable, and to further increase stability, a facile one-step in-situ polymerization process is used to synthesize Si/polydopamine (Si/DPA) nanocomposites, in which ∼2 nm of polydopamine (DPA) uniformly coats the surface of the Si. The as-prepared electrodes exhibit higher capacity than previously reported Si/DPA composites: 2000 mAh g−1 at ∼700 mA g−1, with a 66% retention after 100 cycles. A 15% higher capacity retention is observed herein for the Si/DPA nanocomposite electrode compared with the pure nano-Si electrode. The enhanced capacity retention of the nanocomposite electrode can be attributed to the engineered polymeric layer which can alter the stresses experienced by the Si surface during lithiation and enhances adhesion within the nanocomposite electrode.

Original languageEnglish (US)
Article number138993
JournalElectrochimica Acta
Volume392
DOIs
StatePublished - Oct 2021

Keywords

  • Electron microscopy
  • Fracture
  • Li-ion
  • Phase field
  • Si anode
  • Si/polymer

ASJC Scopus subject areas

  • Chemical Engineering(all)
  • Electrochemistry

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