Reducing Interfacial Resistance between Garnet-Structured Solid-State Electrolyte and Li-Metal Anode by a Germanium Layer

Wei Luo, Yunhui Gong, Yizhou Zhu, Yiju Li, Yonggang Yao, Ying Zhang, Kun Kelvin Fu, Glenn Pastel, Chuan Fu Lin, Yifei Mo, Eric D. Wachsman*, Liangbing Hu

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

278 Scopus citations

Abstract

Substantial efforts are underway to develop all-solid-state Li batteries (SSLiBs) toward high safety, high power density, and high energy density. Garnet-structured solid-state electrolyte exhibits great promise for SSLiBs owing to its high Li-ion conductivity, wide potential window, and sufficient thermal/chemical stability. A major challenge of garnet is that the contact between the garnet and the Li-metal anodes is poor due to the rigidity of the garnet, which leads to limited active sites and large interfacial resistance. This study proposes a new methodology for reducing the garnet/Li-metal interfacial resistance by depositing a thin germanium (Ge) (20 nm) layer on garnet. By applying this approach, the garnet/Li-metal interfacial resistance decreases from ≈900 to ≈115 Ω cm2 due to an alloying reaction between the Li metal and the Ge. In agreement with experiments, first-principles calculation confirms the good stability and improved wetting at the interface between the lithiated Ge layer and garnet. In this way, this unique Ge modification technique enables a stable cycling performance of a full cell of lithium metal, garnet electrolyte, and LiFePO4 cathode at room temperature.

Original languageEnglish
Article number1606042
JournalAdvanced Materials
Volume29
Issue number22
DOIs
StatePublished - 13 Jun 2017
Externally publishedYes

Keywords

  • first-principles calculations
  • garnet
  • Li-metal anodes
  • reducing interfacial resistance
  • solid-state electrolytes

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