Title: Asymmetric Reaction Pathways of Conversion-Type Electrodes for Lithium-Ion Batteries

Abstract

Metal oxides have been actively explored as promising conversion-type electrode materials for lithium ion batteries due to high deliverable capacity but still notorious for poor cyclability, capacity fading, voltage hysteresis, etc. Yet, the fundamental reason for the undesirable properties of metal oxides behind the repetitive conversion process is still obscure. In this work, we take advantage of synchrotron X-ray techniques as well as transmission electron microscopy to monitor the structural changes during both conversion (lithiation) and reconversion (delithiation) reactions. Difference in diffusion rates of lithium and metal plays a decisive role in determining the reaction pathway. We find lithium accommodation and extraction occur via different reaction routes: lithiation follows a kinetically driven way while delithiation adopts a route close to the thermodynamic ground state path. Thermodynamic structural evolution features the formation of an intermediate phase of Li-Metal (M)-O, suggesting lithium removal accompanies with the Li/M ionic exchange and rearrangement of oxygen framework. The slow diffusion of metal ions and the high kinetic and energy barrier for dissociating the intermediate phase are mainly responsible for uncompleted reconversion reaction, evidenced by remaining Li-M-O phase at the end of charge. Imperfect reconversion reaction eventually limits the utilization of lithium ions over the repeatedmore » cycling. Furthermore, this work sheds light on structural changes occurring at metal oxides during both conversion and reconversion processes, which is strongly linked with the performances of conversion-type materials in applications.« less

Authors:

Li, Shuang ^[1]; Shadike, Zulipiya ^[2]; Kwon, Gihan  ^[2];

• Search DOE PAGES for author "Kwon, Gihan"
• Search DOE PAGES for ORCID "0000-0002-7963-2136"

Yang, Xiao-Qing  ^[2];

• Search DOE PAGES for author "Yang, Xiao-Qing"
• Search DOE PAGES for ORCID "0000-0002-3625-3478"

Lee, Ji Hoon  ^[3];

• Search DOE PAGES for author "Lee, Ji Hoon"
• Search DOE PAGES for ORCID "0000-0002-6459-7120"

Hwang, Sooyeon  ^[2]

• Search DOE PAGES for author "Hwang, Sooyeon"
• Search DOE PAGES for ORCID "0000-0001-5606-6728"

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+ Show Author Affiliations

1. Brookhaven National Lab. (BNL), Upton, NY (United States); Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
2. Brookhaven National Lab. (BNL), Upton, NY (United States)
3. Kyungpook National Univ., Daegu (Korea)

Publication Date:

Tue Apr 27 00:00:00 EDT 2021

Research Org.:

Brookhaven National Laboratory (BNL), Upton, NY (United States)

Sponsoring Org.:

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

OSTI Identifier:

1782543

Report Number(s):

BNL-221364-2021-JAAM
Journal ID: ISSN 0897-4756

Grant/Contract Number:  

SC0012704

Resource Type:

Accepted Manuscript

Journal Name:

Chemistry of Materials

Additional Journal Information:

Journal Volume: 33; Journal Issue: 10; Journal ID: ISSN 0897-4756

Publisher:

American Chemical Society (ACS)

Country of Publication:

United States

Language:

English

Subject:

25 ENERGY STORAGE; Chemical reactions; Oxides; Materials; Electrodes; Ions