Surface Modification of Ga-Doped-LLZO (Li7La3Zr2O12) by the Addition of Polyacrylonitrile for the Electrochemical Stability of Composite Solid Electrolytes

Hyewoo Noh, Daeil Kim, Wooyoung Lee, Boyun Jang, Jeong Sook Ha, Ji Haeng Yu

Research output: Contribution to journalArticlepeer-review

Abstract

Composite solid electrolytes (CSEs), often incorporating succinonitrile (SCN), offer promi I confirm sing solutions for improving the performance of all-solid-state batteries. These electrolytes are typically made of ceramics such as Li7La3Zr2O12 (LLZO) and polymers such as poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP). Garnet-applied polymer–ceramic electrolyte (g-PCE) is composed of PVDF-HFP, SCN, and LLZO. However, the interface between SCN and LLZO is reportedly unstable owing to the polymerization of SCN. This polymerization could cause two serious problems: (1) gelation during the mixing of LLZO and SCN and (2) degradation of ionic performance during charge and discharge. To prevent this catalytic reaction, polyacrylonitrile (PAN) can be added to the g-PCE (g-PPCE). PAN blocks the polymerization of SCN through a cyclization process involving La ions which occurs more rapidly than SCN polymerization. In this study, the enhanced chemical stability of the garnet-applied PAN-added polymer ceramic electrolyte (g-PPCE) was achieved by using an impregnation process which added SCN with 5 wt.% of PAN. The resulting CSE has an ionic conductivity of ~10-⁴ S/cm at room temperature. Coin-type cells assembled with LFP (LiFePO4) and LNCM (LiNi0.6Co0.2Mn0.2O2) cathodes with Li-metal anodes show specific discharge capacities of 150 and 167 mAh/g at 0.1 C, respectively, and stable cycle performance. Additionally, a pouch-type cell with a discharge capacity of 5 mAh also exhibits potential electrochemical performance.

Original languageEnglish
Article number7695
JournalEnergies
Volume16
Issue number23
DOIs
Publication statusPublished - 2023 Dec

Bibliographical note

Publisher Copyright:
© 2023 by the authors.

Keywords

  • composite solid electrolyte
  • cyclization
  • garnet oxide
  • polymerization
  • solid-state Li-metal battery

ASJC Scopus subject areas

  • Renewable Energy, Sustainability and the Environment
  • Fuel Technology
  • Engineering (miscellaneous)
  • Energy Engineering and Power Technology
  • Energy (miscellaneous)
  • Control and Optimization
  • Electrical and Electronic Engineering

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