US-12620628-B2 - Alcohol-based electrolytes for highly reversible Zn metal batteries

US12620628B2US 12620628 B2US12620628 B2US 12620628B2US-12620628-B2

Abstract

An electrochemical cell includes a negative electrode including a metal, metal alloy, or an electrode active material that reversibly intercalates and de-intercalates cations; a positive electrode including (i) an electrode active material that reversibly intercalates and de-intercalates cations or anions, or (ii) an inert host that reversibly catalyzes an external reactant; a separator between the negative electrode and the positive electrode; and an electrolyte including one or more alcohol-based solvents, with one or more salts. The solvents may include methanol, ethanol, isopropanol, triglycerol, 2,2,2-trifluoroethanol, an organic small molecule or macromolecule that contain at least one hydroxyl (OH) group, or a combination thereof. The electrochemical cell may include a mixture of multiple alcohol-based solvents or a mixture of the one or more alcohol-based solvents with water, mixed at select ratios. The electrochemical cell may include one or more additives having a concentration range between 0.01% to 20% by weight.

Inventors

Lin Ma
Marshall A. SCHROEDER
Oleg A. BORODIN
Travis P. Pollard
Michael S. Ding
Kang Xu

Assignees

U.S. Army DEVCOM, Army Research Laboratory

Dates

Publication Date: 20260505
Application Date: 20211117

Claims (11)

1 . An electrochemical cell comprising: a negative electrode comprising an electrode active material that reversibly plates and strips multivalent cations; a positive electrode comprising (i) an electrode active material that reversibly intercalates and de-intercalates cations or anions, or (ii) an inert host that reversibly catalyzes an external reactant; a separator between the negative electrode and the positive electrode; and non-aqueous electrolyte comprising one or more alcohol-based solvents, with one or more non-alkali metal salts, wherein a total mass of the alcohol-based solvents comprises more than 20% of a total mass of the electrolyte, wherein the one or more alcohol-based solvents (comprising at least one hydroxyl (OH) group) comprise methanol, ethanol, isopropanol, triglycerol, 2,2,2-trifluoroethanol, or a combination thereof, wherein the one or more non-alkali metal salts are dissolved in a concentration range between 0.1M to 4M.
2 . The electrochemical cell of claim 1 , comprising a mixture of multiple alcohol-based solvents.
3 . The electrochemical cell of claim 1 , comprising one or more electrolyte additives comprising a concentration range between 0.01% to 20% by weight of the electrolyte.
4 . The electrochemical cell of claim 1 , wherein the one or more salts comprise a zinc salt, wherein the zinc salt comprises any of a zinc cation and an inorganic or organic anion.
5 . The electrochemical cell of claim 1 , wherein the zinc salt comprises zinc trifluoromethanesulfonate, zinc bis(trifluoromethane) sulfonimide, zinc chloride, zinc sulfate, zinc nitrate, zinc bromide, zinc fluoride, zinc perchlorate or zinc acetate, or a combination thereof.
6 . The electrochemical cell of claim 1 , wherein the cations comprise any of Zn2+, Mg2+, Ca2+, H+, and Al3+.
7 . The electrochemical cell of claim 1 , wherein the anions comprise any of trifluoromethanesulfonate (OTF—), bis(trifluoromethane) sulfonamide (TFSI—), chloride (Cl—), sulfate (SO42-), nitrate (NO3-), bromide (Br—), fluoride (F—), perchlorate (ClO4-), and acetate (C2H3O2-).
8 . A zinc metal battery comprising: a negative electrode comprising a metal or metal alloy that reversibly plates and strips cations, wherein the cations comprise any of Zn2+, Mg2+, Ca2+, Al3+; a positive electrode comprising an electrode active material that reversibly intercalates or de-intercalates cations or anions, wherein the cations comprise any of Zn2+, Mg2+, Ca2+, Al3+, and H+, and wherein the anions comprise any of trifluoromethanesulfonate (OTF—), bis(trifluoromethane) sulfonamide (TFSI—), chloride (Cl—), sulfate (SO42-), nitrate (NO3-), bromide (Br—), fluoride (F—), perchlorate (ClO4-), and acetate (C2H3O2-); a separator between the negative electrode and the positive electrode; and a non-aqueous electrolyte comprising one or more alcohol-based solvents, with one or more zinc salts over a concentration range between 0.1M to 4M, wherein a total mass of the alcohol-based solvents comprises more than 20% of a total mass of the electrolyte.
9 . The zinc metal battery of claim 8 , wherein the one or more alcohol-based solvents comprise methanol, ethanol, isopropanol, triglycerol, 2,2,2-trifluoroethanol, or a combination thereof.
10 . The zinc metal battery of claim 8 , wherein the one or more zinc salts comprises any of zinc trifluoromethanesulfonate, zinc bis(trifluoromethane) sulfonimide, zinc chloride, zinc sulfate, zinc nitrate, zinc bromide, zinc fluoride, zinc perchlorate, and zinc acetate.
11 . The zinc metal battery of claim 8 , comprising one or more electrolyte additives comprising a concentration range between 0.01% to 20% by weight of the electrolyte.

Description

GOVERNMENT INTEREST The embodiments herein may be manufactured, used, and/or licensed by or for the United States Government without the payment of royalties thereon. BACKGROUND Technical Field The embodiments herein generally relate to electrolytes for metal batteries, and more particularly to alcohol-based electrolytes. Description of the Related Art Water-based electrolytes are the most studied platform for zinc metal batteries. Despite years of research attempting to optimize these systems for rechargeable zinc batteries, aqueous systems are still plagued with issues like hydrogen evolution and dendrite growth which limit capacity retention and cycle life. Other classes of non-aqueous solvents have also been considered, such as nitriles (acetonitrile), alkyl phosphates (trimethylphosphate), and imides (urea), but each of these systems still face efficiency barriers preventing commercialization. Solvent-free compositions such as deep eutectic salts have also been investigated but are generally costly and tend to have a limited temperature window of operation. Most electrolytes for Zn metal batteries suffer from electrolyte/metal anode parasitic reactions, which reduce the efficiency of the battery. Even optimized aqueous/non-aqueous electrolyte formations are not capable of cycling Zn metal anode at reasonable areal capacities (>1 mAh cm2) and current densities (>0.25 mA/cm2) with high efficiency (>95%). For rechargeable batteries with a Zn metal anode to become commercially viable, electrolytes with significantly higher efficiencies must be developed. SUMMARY In view of the foregoing, the embodiments herein provide an electrochemical cell comprising a negative electrode comprising a metal, metal alloy, or an electrode active material that reversibly intercalates and de-intercalates cations; a positive electrode comprising (i) an electrode active material that reversibly intercalates and de-intercalates cations or anions, or (ii) an inert host that reversibly catalyzes an external reactant; a separator between the negative electrode and the positive electrode; and an electrolyte comprising one or more alcohol-based solvents, with one or more salts. The one or more alcohol-based solvents may comprise methanol, ethanol, isopropanol, triglycerol, 2,2,2-trifluoroethanol, an organic small molecule or macromolecule that contain at least one hydroxyl (OH) group, or a combination thereof. The electrochemical cell may comprise a mixture of multiple alcohol-based solvents mixed at select ratios. The electrochemical cell may comprise a mixture of the one or more alcohol-based solvents with water at select ratios. The electrochemical cell may comprise one or more additives comprising a concentration range between 0.01% to 20% by weight. The one or more salts may comprise a zinc salt. The zinc salt may comprise any of a zinc cation and an inorganic or organic anion. The zinc salt may comprise zinc trifluoromethanesulfonate, zinc bis(trifluoromethane)sulfonimide, zinc chloride, zinc sulfate, zinc nitrate, zinc bromide, zinc fluoride, zinc perchlorate or zinc acetate, or a combination thereof at select ratios. The cations may comprise any of Zn2+, Mg2+, Ca2+, H+, and Al3+. The anions may comprise any of trifluoromethanesulfonate (OTF−), bis(trifluoromethane)sulfonamide (TFSI−), chloride (Cl−), sulfate (SO42−), nitrate (NO3−), bromide (Br−), fluoride (F−), perchlorate (ClO4−), and acetate (C2H3O2−). The separator may comprise a porous polyolefin material. The separator may comprise a glass microfiber material. The separator may comprise a polymer material that is gellable with the electrolyte. The separator may comprise a ceramic solid electrolyte material. The separator may comprise a glass solid electrolyte material. The one or more salts may be dissolved in a concentration range between 0.1M to 4M. Another embodiment provides a zinc metal battery comprising a negative electrode comprising a metal, metal alloy, or an electrode active material that reversibly plates and strips cations, wherein the cations comprise any of Zn2+, Mg2+, Ca2+, Al3+; a positive electrode comprising an electrode active material that reversibly intercalates or de-intercalates cations or anions, wherein the cations comprise any of Zn2+, Mg2+, Ca2+, Al3+, and H+, and wherein the anions comprise any of trifluoromethanesulfonate (OTF−), bis(trifluoromethane)sulfonamide (TFSI−), chloride (Cl−), sulfate (SO42−), nitrate (NO3−), bromide (Br−), fluoride (F−), perchlorate (ClO4−), and acetate (C2H3O2−); a separator between the negative electrode and the positive electrode; and an aqueous or non-aqueous electrolyte comprising one or more alcohol-based solvents, with one or more zinc salts over a concentration range between 0.1M to 4M. The one or more alcohol-based solvents may comprise methanol, ethanol, isopropanol, triglycerol, 2,2,2-trifluoroethanol, or a combination thereof. The one or more zinc salts may comprise any of zinc trifluoromethanesulfona