Issue 31, 2020

The natural critical current density limit for Li7La3Zr2O12 garnets

Abstract

Ceramic batteries equipped with Li-metal anodes are expected to double the energy density of conventional Li-ion batteries. Besides high energy densities, also high power is needed when batteries have to be developed for electric vehicles. Practically speaking, so-called critical current densities (CCD) higher than 3 mA cm−2 are needed to realize such systems. As yet, this value has, however, not been achieved for garnet-type Li7La3Zr2O12 (LLZO) being one of the most promising ceramic electrolytes. Most likely, CCD values are influenced by the area specific resistance (ASR) governing ionic transport across the Li|electrolyte interface. Here, single crystals of LLZO with adjusted ASR are used to quantify this relationship in a systematic manner. It turned out that CCD values exponentially decrease with increasing ASR. The highest obtained CCD value was as high as 280 μA cm−2. This value should be regarded as the room-temperature limit for LLZO when no external pressure is applied. Concluding, for polycrystalline samples either stack pressure or a significant increase of the interfacial area is needed to reach current densities equal or higher than the above-mentioned target value.

Graphical abstract: The natural critical current density limit for Li7La3Zr2O12 garnets

Supplementary files

Article information

Article type
Paper
Submitted
29 12 2019
Accepted
09 3 2020
First published
09 3 2020
This article is Open Access
Creative Commons BY license

J. Mater. Chem. A, 2020,8, 15782-15788

The natural critical current density limit for Li7La3Zr2O12 garnets

F. Flatscher, M. Philipp, S. Ganschow, H. M. R. Wilkening and D. Rettenwander, J. Mater. Chem. A, 2020, 8, 15782 DOI: 10.1039/C9TA14177D

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