Title: Uptake of Pb and the Formation of Mixed (Ba,Pb)SO₄ Monolayers on Barite During Cyclic Exposure to Lead-Containing Sulfuric Acid

Abstract

Barite (BaSO₄) is a common additive in lead-acid batteries, where it acts as a nucleating agent to promote the reversible formation and dissolution of PbSO₄ during battery cycling. However, little is known about the molecular-scale mechanisms the nucleation and cyclic evolution of PbSO₄ over a battery’s lifetime. In this study, we explore the responses of a barite (001) surface to cycles of high and low lead concentrations in the presence of 100 mM sulfuric acid using in-situ atomic force microscopy and high-resolution X-ray reflectivity. Here we find that PbSO₄ epitaxial films readily nucleate on the barite surface, even from solutions that are undersaturated relative to bulk PbSO₄. Despite this, barite (001) proves to be an ineffective nucleator of bulk PbSO₄, as multilayer growth is suppressed even in highly supersaturated solutions. Instead, we find evidence that Pb²⁺ ions can directly exchange with Ba²⁺ to create mixed (Ba,Pb)SO₄ surfaces. These chemically mixed surfaces do not host PbSO4 monolayers as readily as pristine barite, and the original reactivity is not regained until a fresh surface is reestablished by aggressive etching. Our results can be partly explained by traditional models of Stranski-Krastanov (S-K) growth, in which monolayer films are stabilized by a reduction inmore » surface energy, but multilayer growth is inhibited by epitaxial strain. Complementary density functional theory calculations confirmed the basic energetic-terms of traditional S-K models, but also showed evidence form more complex, thickness-dependent, energetics than would be predicted from the S-K models. The experimental results can be better understood by extending the S-K model to consider the formation of mixed surfaces and films, which can have reduced strain and interfacial energies relative to pure films, while also being stabilized by entropy of mixing. These insights into non-stoichiometric heteroepitaxy will enable better predictions of how barite affects PbSO₄ nucleation in battery environments.« less

Authors:

Legg, Benjamin A.  ^[1];

• Search DOE PAGES for author "Legg, Benjamin A."
• Search DOE PAGES for ORCID "0000-0002-3055-1829"

Lee, Sang Soo  ^[2];

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• Search DOE PAGES for ORCID "0000-0001-8585-474X"

Garcia, Juan C.  ^[2];

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• Search DOE PAGES for ORCID "0000-0002-5911-8850"

Iddir, Hakim  ^[2];

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• Search DOE PAGES for ORCID "0000-0001-5285-6474"

Fister, Tim T.  ^[2];

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• Search DOE PAGES for ORCID "0000-0001-6537-6170"

Murugesan, Vijayakumar  ^[1]

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• Search DOE PAGES for ORCID "0000-0001-6149-1702"

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+ Show Author Affiliations

1. Pacific Northwest National Laboratory (PNNL), Richland, WA (United States)
2. Argonne National Laboratory (ANL), Argonne, IL (United States)

Publication Date:

Thu Feb 16 00:00:00 EST 2023

Research Org.:

Pacific Northwest National Laboratory (PNNL), Richland, WA (United States); Argonne National Laboratory (ANL), Argonne, IL (United States)

Sponsoring Org.:

USDOE Office of Electricity (OE); USDOE Office of Science (SC), Basic Energy Sciences (BES)

OSTI Identifier:

1964117

Alternate Identifier(s):

OSTI ID: 2305324

Report Number(s):

PNNL-SA-182085
Journal ID: ISSN 1944-8244

Grant/Contract Number:  

AC05-76RL01830; 57558; AC02-06CH11357

Resource Type:

Accepted Manuscript

Journal Name:

ACS Applied Materials and Interfaces

Additional Journal Information:

Journal Volume: 15; Journal Issue: 8; Journal ID: ISSN 1944-8244

Publisher:

American Chemical Society (ACS)

Country of Publication:

United States

Language:

English

Subject:

25 ENERGY STORAGE; energy storage; batteries; crystal growth; nucleation; epitaxy