Effects of polymeric binders on the cracking behavior of silicon composite electrodes during electrochemical cycling

Yikai Wang, Dingying Dang, Dawei Li, Jiazhi Hu, Xiaowen Zhan, Yang Tse Cheng

Research output: Contribution to journalArticlepeer-review

25 Scopus citations

Abstract

Mechanical degradation caused by lithiation/delithiation-induced stress and large volume change is the primary cause of fast capacity fading of silicon (Si)-based electrodes. Although intensive efforts have been devoted to understanding electromechanically induced fractures of electrodes made of Si alone (e.g., Si particles, Si thin films, and Si wafers), the cracking behavior of Si/polymeric binders/carbon black composite electrodes is unclear and poorly understood. Here, we investigate, by in situ and ex situ techniques, the cracking behavior of Si composite electrodes made with different binders, including polyvinylidene fluoride (PVDF), sodium-alginate (SA), sodium-carboxymethyl cellulose (Na-CMC), and Nafion. We found that extensive cracks form during the 1st delithiation process, which periodically open and close during subsequent lithiation/delithiation cycles at the same locations in the Si composite electrodes made with SA, Na-CMC, and Nafion. In contrast, a significantly fewer number of cracks form in the Si/PVDF electrodes after electrochemical cycling. A possible mechanism is proposed to help understand the effects of binders on the cracking behavior (e.g., crack spacing and island size) of Si composite electrodes. We also suggest possible approaches, including reducing the electrode thickness, patterning electrodes, and using highly recoverable binders, to inhibit cracks and improve the mechanical integrity of Si composite electrodes.

Original languageEnglish
Article number226938
JournalJournal of Power Sources
Volume438
DOIs
StatePublished - Oct 31 2019

Bibliographical note

Funding Information:
This work is partially supported by the National Science Foundation Award No. 1355438 . The authors also acknowledge the support by the Assistant Secretary for Energy Efficiency and Renewable Energy, Vehicle Technologies Office of the U.S. Department of Energy Battery Materials Research (BMR) Program under Contract Number DE-EE0007787 . Dr. Souri, Maryam and Dr. Ambrose Seo at Department of Physics & Astronomy, University of Kentucky, are acknowledged for helping with AFM.

Funding Information:
This work is partially supported by the National Science Foundation Award No. 1355438. The authors also acknowledge the support by the Assistant Secretary for Energy Efficiency and Renewable Energy, Vehicle Technologies Office of the U.S. Department of Energy Battery Materials Research (BMR) Program under Contract Number DE-EE0007787. Dr. Souri, Maryam and Dr. Ambrose Seo at Department of Physics & Astronomy, University of Kentucky, are acknowledged for helping with AFM.

Publisher Copyright:
© 2019 Elsevier B.V.

Keywords

  • Adhesion
  • Cracking
  • In situ observation
  • Lithium ion battery
  • Polymeric binder
  • Silicon electrode

ASJC Scopus subject areas

  • Renewable Energy, Sustainability and the Environment
  • Energy Engineering and Power Technology
  • Physical and Theoretical Chemistry
  • Electrical and Electronic Engineering

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