Journal Article

FZJ-2021-03326

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Mechanistic Insights into the Pre‐Lithiation of Silicon/Graphite Negative Electrodes in “Dry State” and After Electrolyte Addition Using Passivated Lithium Metal Powder

Bärmann, P. (First author) ; Mohrhardt, M.FZJ* ; Frerichs, J. E. ; Helling, M. ; Kolesnikov, A. ; Klabunde, S. ; Nowak, S. ; Hansen, M. R. ; Winter, M. (Corresponding author)FZJ* ; Placke, T. (Corresponding author)

2021
Wiley-VCH Weinheim

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Please use a persistent id in citations: http://hdl.handle.net/2128/28573  doi:10.1002/aenm.202100925

Abstract: Because of its high specific capacity, silicon is regarded as the most promising candidate to be incrementally added to graphite-based negative electrodes in lithium-ion batteries. However, silicon suffers from significant volume changes upon (de-)lithiation leading to continuous re-formation of the solid electrolyte interphase (SEI) and ongoing active lithium losses. One prominent approach to compensate for active lithium losses is pre-lithiation. Here, the “contact pre-lithiation” of silicon/graphite (Si/Gr) negative electrodes in direct contact with passivated Li metal powder (PLMP) is studied, focusing on the pre-lithiation mechanism in “dry state” and after electrolyte addition. PLMP is pressed onto the electrode surface to precisely adjust the degree of pre-lithiation (25%, 50%, and 75%). By in situ XRD and ex situ 7Li NMR studies, it is proven that significant lithiation of Si/Gr electrodes occurs by direct contact to Li metal, that is, without electrolyte. After electrolyte addition, de-lithiation of silicon and graphite is confirmed, resulting in SEI formation. The amount of Li metal highly impacts the presence and durability of the LixC and LixSi phases. Finally, the challenges for homogeneous pre-lithiation and SEI formation are identified, and the impact of electrolyte addition is assessed by analysis of the lateral and in-depth lithium distribution within the Si/Gr electrode.

Keyword(s): Chemical Reactions and Advanced Materials (1st) ; Chemistry (2nd) ; Materials Science (2nd)

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Contributing Institute(s):

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

Research Program(s):

1. 1221 - Fundamentals and Materials (POF4-122) (POF4-122)
2. SeNSE - Lithium-ion battery with silicon anode, nickel-rich cathode and in-cell sensor for electric vehicles (875548) (875548)

Appears in the scientific report 2021

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Database coverage:
; ; ; Clarivate Analytics Master Journal List ; Current Contents - Engineering, Computing and Technology ; Current Contents - Physical, Chemical and Earth Sciences ; DEAL Wiley ; Ebsco Academic Search ; Essential Science Indicators ; IF >= 25 ; JCR ; SCOPUS ; Science Citation Index Expanded ; Web of Science Core Collection

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