Journal Article

FZJ-2021-01735

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Area Oversizing of Lithium Metal Electrodes in Solid‐State Batteries: Relevance for Overvoltage and thus Performance?

Stolz, L.FZJ* ; Homann, G.FZJ* ; Winter, M. (Corresponding author)FZJ* ; Kasnatscheew, J. (Corresponding author)FZJ*

2021
Wiley-VCH Weinheim

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Please use a persistent id in citations: http://hdl.handle.net/2128/28318  doi:10.1002/cssc.202100213

Abstract: Systematic and systemic research and development of solid electrolytes for lithium batteries requires a reliable and reproducible benchmark cell system. Therefore, factors relevant for performance, such as temperature, voltage operation range, or specific current, should be defined and reported. However, performance can also be sensitive to apparently inconspicuous and overlooked factors, such as area oversizing of the lithium electrode and the solid electrolyte membrane (relative to the cathode area). In this study, area oversizing is found to diminish polarization and improves the performance in LiNi0.6Mn0.2Co0.2O2 (NMC622)||Li cells, with a more pronounced effect under kinetically harsh conditions (e. g., low temperature and/or high current density). For validity reasons, the polarization behavior is also investigated in Li||Li symmetric cells. Given the mathematical conformity of the characteristic overvoltage behavior with the Sand's equation, the beneficial effect is attributed to lower depletion of Li ions at the electrode/electrolyte interface. In this regard, the highest possible effect of area oversizing on the performance is discussed, that is when the accompanied decrease in current density and overvoltage overcomes the Sand's threshold limit. This scenario entirely prevents the capacity decay attributable to Li+ depletion and is in line with the mathematically predicted values.

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Contributing Institute(s):

1. Helmholtz-Institut Münster Ionenleiter für Energiespeicher (IEK-12)

Research Program(s):

1. 122 - Elektrochemische Energiespeicherung (POF4-122) (POF4-122)

Appears in the scientific report 2021

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Database coverage:
; ; ; Clarivate Analytics Master Journal List ; Current Contents - Physical, Chemical and Earth Sciences ; DEAL Wiley ; Essential Science Indicators ; IF >= 5 ; JCR ; SCOPUS ; Science Citation Index Expanded ; Web of Science Core Collection

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