Spatial Molecular Layer Deposition of Ultrathin Polyamide to Stabilize Silicon Anodes in Lithium-Ion Batteries

Jasmine M. Wallas, Brian C. Welch, Yikai Wang, Jun Liu, Simon E. Hafner, Rui Qiao, Taeho Yoon, Yang Tse Cheng, Steven M. George, Chunmei Ban

Research output: Contribution to journalArticlepeer-review

20 Scopus citations

Abstract

Cycling stability is central to implementing silicon (Si) anodes in next-generation high-energy lithium-ion batteries. However, challenges remain due to the lack of effective strategies to enhance the structural integrity of the anode during electrochemical cycling. Here, we develop a nanoscale polyamide coating, using spatial molecular layer deposition (MLD) of m-phenylenediamine and trimesoyl chloride precursors, to preserve the structural integrity of Si anodes. Poly(acrylic acid) (PAA) has been widely used in Si-based anodes as a binding agent due to its effective binding interactions with Si particles. However, the structural integrity of the anode is compromised by thermochemical decomposition of the poly(acrylic acid) binder, which can occur during electrode drying or during electrochemical cycling. Decomposition causes a 62% decrease in the elastic modulus of the Si anode, as measured by nanoindentation in electrolyte-soaked conditions. This study shows that an ultrathin polyamide coating counteracts this structural degradation, increases the elastic modulus of the degraded anode by 345%, and improves cohesion. Electrochemical analysis of polyamide-coated anodes reveals a film thickness dependence in cycling behavior. High overpotentials and fast capacity fading are observed for Si anodes with a 15 nm coating, whereas Si anodes with a 0.5 nm coating demonstrate stable cycling over 150 cycles with a capacity >1400 mAh g-1. Our findings identify polyamide as an effective electrode coating material to enhance structural integrity, leading to excellent cyclability with higher capacity retention. Furthermore, the use of the spatial MLD approach to deposit the coating enables short deposition time and a facile route to scale-up.

Original languageEnglish
Pages (from-to)4135-4143
Number of pages9
JournalACS Applied Energy Materials
Volume2
Issue number6
DOIs
StatePublished - Jun 24 2019

Bibliographical note

Publisher Copyright:
© Copyright 2019 American Chemical Society.

Keywords

  • lithium-ion batteries
  • molecular layer deposition
  • polyamide
  • silicon anodes
  • surface modification

ASJC Scopus subject areas

  • Chemical Engineering (miscellaneous)
  • Energy Engineering and Power Technology
  • Electrochemistry
  • Materials Chemistry
  • Electrical and Electronic Engineering

Fingerprint

Dive into the research topics of 'Spatial Molecular Layer Deposition of Ultrathin Polyamide to Stabilize Silicon Anodes in Lithium-Ion Batteries'. Together they form a unique fingerprint.

Cite this