Dual interface design of Ga-doped Li7La3Zr2O12/polymer composite electrolyte for solid-state lithium batteries

Purna Chandra Rath, Wei Lun Hsu, Cheng Chia Chen, Chih Yang Huang, Wen Wei Wu, Shigeto Okada, Quan Feng Dong, Chun Chen Yang, Tai Chou Lee, Jeng Kuei Chang

Research output: Contribution to journalArticlepeer-review

Abstract

Solid-state lithium-metal batteries (SSLMBs) with a Li7La3Zr2O12-based composite solid electrolyte (CSE) show great potential for overcoming the safety and specific energy concerns of conventional liquid-electrolyte Li-ion batteries. Nevertheless, achieving a satisfactory connection between a solid electrolyte and the cathode and anode materials is a major challenge. A dual interface modification strategy is proposed here to address this problem. CSEs with various fractions of Ga-doped Li7La3Zr2O12 (LGLZO), polyethylene oxide (PEO), and lithium bis(trifluorosulfonyl)imide (LiTFSI) are spin-coated directly onto a lithium iron phosphate (LFP) cathode to improve the cathode/CSE interfacial contact and establish a Li+ conducting network within the cathode. The effects of the Ga concentration in LGLZO on CSE conductivity and battery performance are investigated. The LGLZO:PEO:LiTFSI fraction and the number of spin-coated layers are adjusted to optimize battery performance. The advantage of a spin-coated CSE over a freestanding CSE in terms of reducing the migration barrier is demonstrated. In addition, an ionic liquid (IL) interconnection layer is incorporated at the Li/CSE junction to improve wettability. The effects of two IL anions, namely bis(fluorosulfonyl)imide (FSI) and bis(trifluorosulfonyl)imide (TFSI), on interfacial modification are systematically investigated. The optimal ionic conductivity of the CSE is ~1.0 × 10−3 S cm−1 at 60 °C. With this SSLMB configuration, the specific LFP capacities are 150 and 141 mAh g−1 at 0.1 and 1 C, respectively. Capacity retention of ~96% after 300 cycles is demonstrated.

Original languageEnglish
Pages (from-to)17693-17705
Number of pages13
JournalInternational Journal of Energy Research
Volume46
Issue number12
DOIs
StatePublished - 10 Oct 2022

Keywords

  • Ga concentration
  • interface modification
  • ionic liquid interlayer
  • solid electrolyte
  • spin coating

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