Title: Surface SiO₂ Thickness Controls Uniform-to-Localized Transition in Lithiation of Silicon Anodes for Lithium-Ion Batteries

Abstract

Silicon is a promising anode material for lithium-ion batteries because of its high capacity, but its widespread adoption has been hampered by a low cycle life arising from mechanical failure and the absence of a stable solid–electrolyte interphase (SEI). Understanding SEI formation and its impact on cycle life is made more complex by the oxidation of silicon materials in air or during synthesis, which leads to SiO_x coatings of varying thicknesses that form the true surface of the electrode. Here, the lithiation of SiO₂-coated Si is studied in a controlled manner using SiO₂ coatings of different thicknesses grown on Si wafers via thermal oxidation. SiO₂ thickness has a profound effect on lithiation: below 2 nm, SEI formation followed by uniform lithiation occurs at positive voltages versus Li/Li⁺. Si lithiation is reversible, and SiO₂ lithiation is largely irreversible. Above 2 nm SiO₂, voltammetric currents decrease exponentially with SiO₂ thickness. For 2–3 nm SiO₂, SEI formation above 0.1 V is suppressed, but a hold at low or negative voltages can initiate charge transfer whereupon SEI formation and uniform lithiation occur. Cycling of Si anodes with an SiO₂ coating thinner than 3 nm occurs at high Coulombic efficiency (CE). If an SiO₂ coatingmore » is thicker than 3–4 nm, the behavior is totally different: lithiation at positive voltages is strongly inhibited, and lithiation occurs at poor CE and is highly localized at pinholes which grow over time. As they grow, lithiation becomes more facile and the CE increases. Pinhole growth is proposed to occur via rapid transport of Li along the SiO₂/Si interface radially outward from an existing pinhole, followed by the lithiation of SiO₂ from the interface outward.« less

Authors:

Schnabel, Manuel  ^[1];

• Search DOE PAGES for author "Schnabel, Manuel"
• Search DOE PAGES for ORCID "0000-0001-6664-7884"

Harvey, Steven P.  ^[1];

• Search DOE PAGES for author "Harvey, Steven P."
• Search DOE PAGES for ORCID "0000-0001-6120-7062"

Arca, Elisabetta  ^[2];

• Search DOE PAGES for author "Arca, Elisabetta"
• Search DOE PAGES for ORCID "0000-0003-0651-6000"

Stetson, Caleb  ^[1];

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• Search DOE PAGES for ORCID "0000-0003-0729-1261"

Teeter, Glenn ^[1]; Ban, Chunmei  ^[1];

• Search DOE PAGES for author "Ban, Chunmei"
• Search DOE PAGES for ORCID "0000-0002-1472-1496"

Stradins, Paul ^[1]

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+ Show Author Affiliations

1. National Renewable Energy Lab. (NREL), Golden, CO (United States)
2. National Renewable Energy Lab. (NREL), Golden, CO (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

Publication Date:

Thu May 14 00:00:00 EDT 2020

Research Org.:

National Renewable Energy Lab. (NREL), Golden, CO (United States)

Sponsoring Org.:

USDOE Office of Energy Efficiency and Renewable Energy (EERE), Transportation Office. Vehicle Technologies Office

OSTI Identifier:

1660028

Report Number(s):

NREL/JA-5900-76182
Journal ID: ISSN 1944-8244; MainId:7021;UUID:e4afa06e-0555-ea11-9c31-ac162d87dfe5;MainAdminID:13788

Grant/Contract Number:  

AC36-08GO28308

Resource Type:

Accepted Manuscript

Journal Name:

ACS Applied Materials and Interfaces

Additional Journal Information:

Journal Volume: 12; Journal Issue: 24; Journal ID: ISSN 1944-8244

Publisher:

American Chemical Society (ACS)

Country of Publication:

United States

Language:

English

Subject:

25 ENERGY STORAGE; carbonate electrolyte; lithiation; lithium ion battery; pinhole; silicon anode; silicon oxide; solid-electrolyte interphase