Garnet Electrolyte with an Ultralow Interfacial Resistance for Li-Metal Batteries

Yutao LI, Xi CHEN, Andrei DOLOCAN, Zhiming CUI, Sen XIN, Leigang XUE, Henghui XU, Kyusung PARK, John B. GOODENOUGH*

*Corresponding author for this work

Research output: Journal PublicationsJournal Article (refereed)peer-review

422 Citations (Scopus)

Abstract

Garnet-structured Li7La3Zr2O12 is a promising solid Li-ion electrolyte for all-solid-state Li-metal batteries and Li-redox-flow batteries owing to its high Li-ion conductivity at room temperature and good electrochemical stability with Li metal. However, there are still three major challenges unsolved: (1) the controversial electrochemical window of garnet, (2) the impractically large resistance at a garnet/electrode interface and the fast lithium-dendrite growth along the grain boundaries of the garnet pellet, and (3) the fast degradation during storage. We have found that these challenges are closely related to a thick Li2CO3 layer and the Li-Al-O glass phase on the surface of garnet materials. Here we introduce a simple method to remove Li2CO3 and the protons in the garnet framework by reacting garnet with carbon at 700 °C; moreover, the amount of the Li-Al-O glass phase with a low Li-ion conductivity in the grain boundary on the garnet surface was also reduced. The surface of the carbon-treated garnet pellets is free of Li2CO3 and is wet by a metallic lithium anode, an organic electrolyte, and a solid composite cathode. The carbon post-treatment has reduced significantly the interfacial resistances to 28, 92 (at 65 °C), and 45 ω cm2 at Li/garnet, garnet/LiFePO4, and garnet/organic-liquid interfaces, respectively. A symmetric Li/garnet/Li, an all-solid-state Li/garnet/LiFePO4, and a hybrid Li-S cell show small overpotentials, high Coulombic efficiencies, and stable cycling performance. © 2018 American Chemical Society.
Original languageEnglish
Pages (from-to)6448-6455
Number of pages8
JournalJournal of the American Chemical Society
Volume140
Issue number20
Early online date24 Apr 2018
DOIs
Publication statusPublished - 23 May 2018
Externally publishedYes

Bibliographical note

This work is supported by the Assistant Secretary for Energy Efficiency and Renewable Energy, Office of Vehicle Technologies of the U.S. Department of Energy through the Advanced Battery Materials Research (BMR) Program (Battery500 Consortium) award number DE-EE0007762.

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