Journal of Materials Research and Technology (Nov 2021)

Cubic garnet solid polymer electrolyte for room temperature operable all-solid-state-battery

  • Van Tung Luu,
  • Quoc Hung Nguyen,
  • Moon Gyu Park,
  • Hoang Long Nguyen,
  • Min-Ho Seo,
  • Soon-Ki Jeong,
  • Namchul Cho,
  • Young-Woo Lee,
  • Younghyun Cho,
  • Sung Nam Lim,
  • Yun-Seok Jun,
  • Wook Ahn

Journal volume & issue
Vol. 15
pp. 5849 – 5863

Abstract

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Solid polymer electrolytes are promising candidates for implementation in next-generation all-solid-state batteries (ASSBs) which could replace conventional batteries used today. However, the materialization of ASSBs on a mass scale is restricted by the low ionic conductivity and high interfacial resistance of solid electrolytes. In this work, succinonitrile (SN) with lithium (trifluoromethylsulphonyl)imide (LiTFSI) and Al-doped Li7La3Zr2O12 (Al-LLZO) nanoparticles were used to improve the ionic conductivity of a polyethylene oxide-based composite electrolyte. The Al-LLZO nanoparticles were synthesized by a facile synthesis process at low temperatures, which contributed to an enhancement in the ionic conductivity. A solid polymer electrolyte with 7.5 wt% of Al-LLZO and 15 wt% of SN achieved a high ionic conductivity of 4.17 × 10−4 Scm−1 at room temperature and a large value of 0.451 for the lithium-ion transport number at 60 °C. By adding 10 wt% SN and 10 wt% of Al-LLZO in the LiFePO4 cathode, the cell could operate at 25 °C with a specific capacity of 130 mAh g−1 and 89% capacity retention after 200 cycles at current density of 20 mA g−1. This study therefore proposes a solution to improve the ionic conductivity of solid polymer electrolytes in all-solid-state batteries.

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