Title: Anion Association Strength as a Unifying Descriptor for the Reversibility of Divalent Metal Deposition in Nonaqueous Electrolytes

Abstract

Developing next-generation battery chemistries that move beyond traditional Li-ion systems is critical to enabling transformative advances in electrified transportation and grid-level energy storage. Here, we provide the first evidence for common descriptors for improved reversibility of metal plating/stripping in nonaqueous electrolytes for multivalent ion batteries. Focusing first on the specific role of chloride (Cl^–) in promoting electrochemical reversibility in multivalent systems, rotating disk (RDE) and ring-disk electrode (RRDE) investigations were performed utilizing a variety of divalent cations (Mg²⁺, Zn²⁺, and Cu²⁺) and the bis-(trifluoromethane sulfonyl) imide (TFSI^–) anion. By introducing varying concentrations of Cl^–, a cooperative effect is observed between TFSI^– and Cl^– that yields the more reversible behavior of mixed electrolytes relative to electrolytes containing only TFSI^–. This effect is shown to be general for Mg, Zn, and Cu electrodeposition, and mechanistic understanding of the role of Cl^– in improving reversibility of TFSI-based electrolytes is obtained through the combination of R(R)DE experimental results and density functional theory (DFT) evaluation of the redox activity and thermodynamic stability of various TFSI- and Cl-based solution complexes of metal ions. The cooperative anion effect is further generalized to other mixed-anion systems, where systematic variations in anion association strength predicted from DFT (i.e., Cl^–more » > OTf^– ≈ TFSI^– > BF₄^– > PF₆^–) yield corresponding trends in redox potentials and improvements of ≥200 mV in the reversibility of metal deposition/dissolution. These results identify anion association strength as a common descriptor for the reversibility of divalent metal anodes and suggest a set of general design principles for developing new electrolytes with improved activity and stability.« less

Authors:

Connell, Justin G.  ^[1];

• Search DOE PAGES for author "Connell, Justin G."
• Search DOE PAGES for ORCID "0000-0002-2979-2131"

Zorko, Milena ^[2]; Agarwal, Garvit ^[1]; Yang, Mengxi ^[1]; Liao, Chen  ^[1];

• Search DOE PAGES for author "Liao, Chen"
• Search DOE PAGES for ORCID "0000-0001-5168-6493"

Assary, Rajeev S.  ^[1];

• Search DOE PAGES for author "Assary, Rajeev S."
• Search DOE PAGES for ORCID "0000-0002-9571-3307"

Strmcnik, Dusan ^[1]; Markovic, Nenad M. ^[1]

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+ Show Author Affiliations

1. Argonne National Laboratory (ANL), Lemont, IL (United States). Joint Center for Energy Storage Research (JCESR)
2. Argonne National Laboratory (ANL), Lemont, IL (United States). Joint Center for Energy Storage Research (JCESR); National Inst. of Chemistry, Ljubljana (Slovenia)

Publication Date:

Wed Jul 15 00:00:00 EDT 2020

Research Org.:

Argonne National Lab. (ANL), Argonne, IL (United States). Joint Center for Energy Storage Research (JCESR); Argonne National Laboratory (ANL), Argonne, IL (United States). Laboratory Computing Resource Center (LCRC) and Center for Nanoscale Materials (CNM)

Sponsoring Org.:

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

OSTI Identifier:

1661667

Grant/Contract Number:  

AC02-06CH11357

Resource Type:

Accepted Manuscript

Journal Name:

ACS Applied Materials and Interfaces

Additional Journal Information:

Journal Volume: 12; Journal Issue: 32; Journal ID: ISSN 1944-8244

Publisher:

American Chemical Society (ACS)

Country of Publication:

United States

Language:

English

Subject:

25 ENERGY STORAGE; Battery; Electrochemistry; Electrolyte Design; Magnesium; Metal Deposition; Zinc