ACS Appl Mater Interfaces. 2015 Jan 28;7(3):2073-81. doi: 10.1021/am508111r. Epub 2015 Jan 17.

Effect of surface microstructure on electrochemical performance of garnet solid electrolytes.

ACS applied materials & interfaces

Lei Cheng, Wei Chen, Martin Kunz, Kristin Persson, Nobumichi Tamura, Guoying Chen, Marca Doeff

PMID: 25563572 DOI: 10.1021/am508111r

Abstract

Cubic garnet phases based on Al-substituted Li7La3Zr2O12 (LLZO) have high ionic conductivities and exhibit good stability versus metallic lithium, making them of particular interest for use in next-generation rechargeable battery systems. However, high interfacial impedances have precluded their successful utilization in such devices until the present. Careful engineering of the surface microstructure, especially the grain boundaries, is critical to achieving low interfacial resistances and enabling long-term stable cycling with lithium metal. This study presents the fabrication of LLZO heterostructured solid electrolytes, which allowed direct correlation of surface microstructure with the electrochemical characteristics of the interface. Grain orientations and grain boundary distributions of samples with differing microstructures were mapped using high-resolution synchrotron polychromatic X-ray Laue microdiffraction. The electrochemical characteristics are strongly dependent upon surface microstructure, with small grained samples exhibiting much lower interfacial resistances and better cycling behavior than those with larger grain sizes. Low area specific resistances of 37 Ω cm(2) were achieved; low enough to ensure stable cycling with minimal polarization losses, thus removing a significant obstacle toward practical implementation of solid electrolytes in high energy density batteries.

Keywords: heterostructures; interface; lithium metal; solid electrolyte; solid state battery

Publication Types

• Journal Article
• Research Support, U.S. Gov't, Non-P.H.S.