Freeze-dried low-tortuous graphite electrodes with enhanced capacity utilization and rate capability

Dingying Dang, Yikai Wang, Shuang Gao, Yang Tse Cheng

Research output: Contribution to journalArticlepeer-review

28 Scopus citations

Abstract

Lithium ion battery electrodes with high rate capability are important for extreme fast charging (XFC) for electric vehicle applications. Making low-tortuous electrodes is one of the approaches to achieve XFC by enhancing ionic transport in the electrodes. In this study, we conducted directional freeze-drying of slurries cast on a copper foil to make graphite electrodes. Low-tortuous structure was created and verified by cross-sectional scanning electron microscope observations and tortuosity measurements. The out-of-plane alignment of graphite flakes, enhanced electrolyte wettability, and low tortuosity of the freeze-dried electrodes were confirmed by X-ray diffraction measurements, wettability tests, and electrochemical impedance measurements, respectively. Electrochemical measurements showed that the freeze-dried electrodes have higher capacity retention (over 8% higher after 90 cycles at C/5) and better rate capability (60% higher capacity at 1C) than the electrodes prepared by the conventional tape-casting method. These enhancements mainly arise from the improved ionic transport by the freeze-drying induced low-tortuous structure. This study provides a proof-of-concept example that tape-casting/freeze-drying can be an effective, low cost, and scalable method to reduce tortuosity and improve electrochemical performance of battery electrodes.

Original languageEnglish
Pages (from-to)133-139
Number of pages7
JournalCarbon
Volume159
DOIs
StatePublished - Apr 15 2020

Bibliographical note

Publisher Copyright:
© 2019 Elsevier Ltd

ASJC Scopus subject areas

  • General Chemistry
  • General Materials Science

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