2,5-Dimercapto-1,3,4-thiadiazole ("DMTD") zinc salt derivatives

Abstract

The disclosed technology relates to zinc salts of 2,5-dimercapto-1,3,4-thiadiazole ("DMTD") and electrodes therefor for use in zinc ion battery systems.

Description

Background Art

[0001] The disclosed technology relates to zinc salts of 2,5-dimercapto-1,3,4-thiadiazole ("DMTD") and electrodes therefor for use in zinc ion battery systems.

[0002] Organic-based electrode materials are a relatively new consideration for replacing inorganic materials as positive or negative electrodes in batteries. Organic-based materials can be flexible and generally have improved specific capacity and less swelling with cycling compared to inorganic materials. Organic-based materials are also generally more environmentally friendly and cheaper than inorganic materials.

[0003] Some simple alkyl- and aryl-substituted DMTD derivatives are known, for example, US Pat. No. 2,736,729, issued Feb. 28, 1956 to Krzikalla et al. and Oct. 19, 1965 to von Simple alkyl and aryl acrylates of DMTD are also known, for example, as taught in JP 2013234126, published on November 21, 2013, to Oya et al., and US 5,258,395, issued on November 2, 1993, to Murase et al.

[0004] Examples of organic-based electrode chemistries in the art typically begin with some or all relatively expensive starting materials and reagents, may require multiple steps to obtain the desired end product, generate large amounts of undesirable process waste, and may also require tedious purification steps.New materials for organic-based electrodes are needed. Summary of the invention

[0005] Thus, the disclosed technology solves the problem of difficult and expensive to produce but readily oxidizable organic chemicals by providing new DMTD zinc salts that can be synthesized in only one or two steps, starting from readily available and inexpensive starting materials, using processing that produces little or no waste, and involving reactions that proceed rapidly and with high product conversions.

[0006] In particular, the technology provides DMTD derivatives of the formula

[0007]

[0008] Wherein X is a negative charge or H, or a hydrocarbyl group of 1 to 10 carbon atoms.

[0009] The technology also provides an organic-based electrode comprising A) at least one polymer binder, B) at least one conductive material, and C) at least one DMTD derivative as discussed herein.

[0010] Additionally, the technology includes a zinc ion battery system comprising A) a zinc anode, B) an electrolyte of a zinc salt solution, and C) an organic-based electrode disclosed herein. DETAILED DESCRIPTION

[0011] Various preferred features and embodiments will be described below by way of non-limiting illustration.

[0012] Provided herein are zinc salt derivatives of 2,5-dimercapto-1,3,4-thiadiazole ("DMTD"). Generally, the zinc salt derivative of DMTD can be represented by Formula I in pure form:

[0013] Formula I

[0014]

[0015] Wherein X is a negative charge or H, or a hydrocarbyl group.

[0016] In some cases, X in Formula I is a negative charge, in which case Formula I will be represented by the following Formula I':

[0017] Formula I'

[0018]

[0019] In some cases, X may be H, in which case Formula I will be represented by the following Formula I″:

[0020] Formula I"

[0021]

[0022] In some embodiments, X in Formula I can be a hydrocarbyl group. The hydrocarbyl group can be a hydrocarbyl group of 1 to 10 carbon atoms. X can also be a hydrocarbyl group of 1 to 8 carbon atoms. X can also be a hydrocarbyl group of 1 to 6 carbon atoms.

[0023] In some cases, X in Formula I can be a hydrocarbyl group in the form of an alkyl group, in which case the alkyl group can have 1 to 10 carbon atoms. Such a compound can be represented by the following Formula I"':

[0024] Formula I"'

[0025]

[0026] X may also be a hydrocarbyl group in the form of an alkyl group having 1 to 8 carbon atoms. X may also be a hydrocarbyl group in the form of an alkyl group having 1 to 6 carbon atoms.

[0027] In some cases, X in Formula I can be a hydrocarbon group in the form of an amide group, in which case the amide group can have 1 to 10 carbon atoms. Such a compound can be represented by the following Formula I"":

[0028] Formula I""

[0029]

[0030] X may also be a hydrocarbyl group in the form of an amide group having 1 to 8 carbon atoms. X may also be a hydrocarbyl group in the form of an amide group having 1 to 6 carbon atoms.

[0031] The present technology also includes a zinc electrode containing A) a DMTD derivative as discussed above, B) a polymer binder, and C) a conductive material. As used herein, the term "a" in "a" DMTD derivative, "a" polymer binder, or "a" conductive material is not limited to only one of the elements, but is used to mean "at least one", which includes one or more of the elements, as well as two or more, three or more, etc.

[0032] The DMTD derivative may be present at about 40% to 80% by weight of the electrode composition. The DMTD derivative may be present at about 45% to 75% by weight of the electrode composition. The DMTD derivative may be present at about 50% to 70% by weight of the electrode composition. The DMTD derivative may be present at about 55% to 65% by weight of the electrode composition.

[0033] The polymer binders that can be used for the electrode are well known and are not particularly limited in the present zinc electrode composition. The binder is preferably made of a material conventionally known as a binder contained in the positive electrode mixture, and is preferably PVDF (polyvinylidene fluoride), for example. Other examples of polymer binders used in electrodes include, for example, polyamide-imide, polytetrafluoroethylene ("PTFE"), and polyamide. Other exemplary binders include carboxymethyl cellulose ("CMC") and styrene-butadiene rubber ("SBR").

[0034] The polymer binder may be present at about 1 wt % to 20 wt % of the electrode composition. The polymer binder may be present at about 2.5 wt % to 15 wt % of the electrode composition. The polymer binder may be present at about 5 wt % to 10 wt % of the electrode composition.

[0035] As with polymer binders, conductive materials are well known and are not particularly limited in the present zinc electrode composition. The conductive material is preferably made of a material conventionally known as a conductive material contained in a positive electrode mixture, and is preferably, for example, a carbon material, such as carbon black or its subtypes, including acetylene black, channel black, furnace black, lamp black, thermal black, and mixtures thereof. Other examples of conductive materials include vapor grown carbon fibers (VGCF), graphite, and highly ordered mesoporous carbon (OMC). This conductive material may be used alone or in combination of two or more conductive materials.

[0036] The conductive material may be present at about 10% to 40% by weight of the electrode composition. The conductive material may be present at about 15% to 35% by weight of the electrode composition. The conductive material may be present at about 20% to 30% by weight of the electrode composition.

[0037] The zinc electrode can be formed by standard methods known in the art. For example, the ingredients can be formed into a paste, such as in a mortar and pestle or by other mechanical means, and then applied to the desired area of ​​the zinc cell and allowed to dry. Alternatively, wet granulated particles containing the zinc electrode ingredients can also be crimped into the desired area within the cell and allowed to dry.

[0038] The present technology also includes a zinc ion battery system. The zinc ion battery system includes A) the zinc electrode discussed above, B) a zinc anode, and C) an electrolyte containing a zinc salt solution.

[0039] The zinc anode is simply a zinc strip used as a sacrificial anode. Such zinc anodes are commercially available.

[0040] The electrolyte comprises a zinc salt solution. The zinc salt solution can be a solution in a polar solvent. The polar solvent can be any solvent in which the zinc salt is soluble. The polar solvent should also remain inert under the operating conditions of the zinc battery. It is expected that a person of ordinary skill can easily determine the solubility and inertness of a suitable solvent and thus select a suitable solvent. The simplest solvent for the present technology will be water, and in one embodiment, the technology actually provides an aqueous zinc ion battery system comprising A) the zinc electrode discussed above, B) a zinc anode, and C) an electrolyte comprising an aqueous solution of a zinc salt.

[0041] In some embodiments, the polar solvent may also be, for example, an alcohol, such as C 1 To C 10Alcohol or glycol, including for example methanol, ethanol, 1-propanol, 2-propanol, ethylene glycol, propylene glycol. Ethers can also be used as solvents, including for example dimethoxymethane, methoxybenzene (anisole), tetrahydrofuran (THF), 2-methyltetrahydrofuran, 1,4-dioxane, 1,3-dioxolane (DOL), 4-methyl-1,3-dioxolane, 1,2-dimethoxyethane (DME) and bis (2-methoxyethyl) ether (diglyme). Polar solvents can also be ketones, such as acetone or acetylacetone. Nitriles such as, for example, acetonitrile (ACN), methoxyacetonitrile, propionitrile, butyronitrile, isobutyronitrile, benzonitrile and 3-methoxypropionitrile can be used as solvents, as can amines such as ethylenediamine and pyridine, or amides such as formamide, N-methylacetamide, N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMA) and N-methyl-2-pyrrolidone (NMP). The solvent can also be a carbonate. The non-limiting example of carbonate includes propylene carbonate (PC), ethylene carbonate (EC), dimethyl carbonate (DMC), diethyl carbonate (DEC), ethyl methyl carbonate (EMC) and 1,2-butylene carbonate. The solvent can also be a cyclic ester, such as γ-butyrolactone (γ-BL) or γ-valerolactone (γ-VL). Other organic based solvents are also contemplated, such as, for example, hexane, benzene, toluene, nitromethane, nitrobenzene, 1,2-dichloroethane, dimethylsulfoxide (DMSO), ethyl acetate, and nitroethane, to name a few. Combinations of any of the foregoing solvents may also be employed as solvents.

[0042] Zinc salts are well known, commercially available and are not particularly limited in the present technology. The zinc salt of the electrolyte may be, for example, zinc sulfate (ZnSO 4 ), zinc trifluoromethanesulfonate (Zn(OTf)), and combinations thereof. Other examples of zinc salts include: zinc halides, such as zinc bromide, zinc iodide, zinc fluoride, and zinc chloride; zinc carboxylates, such as zinc acetate, zinc citrate, zinc ricinoleate, zinc methacrylate, zinc oxalate, etc.; zinc nitrate; zinc cyanide; zinc phosphate; zinc molybdate; zinc chromate; zinc silicates, such as zinc hexafluorosilicate, etc.

[0043] The zinc salt may be present in the electrolyte solution at a concentration of about 0.05 M to 5 M. The zinc salt may be present in the electrolyte solution at a concentration of about 0.25 M to 4 M. The zinc salt may be present in the electrolyte solution at a concentration of about 0.5 M to 3 M. The zinc salt may be present in the electrolyte solution at a concentration of about 0.75 M to 3 M.

[0044] Unless otherwise indicated, the amount of each chemical component recited does not include any solvent or diluent oil which may be customarily present in the commercial material, i.e., on an active chemical basis. However, unless otherwise indicated, each chemical or composition referred to herein should be interpreted as being a commercial grade material which may contain the isomers, by-products, derivatives, and other such materials which are normally understood to be present in the commercial grade.

[0045] Example

[0046] Example 1. Synthesis of poly-[1,3,4-thiadiazole-2,5-dithiol zinc] - 42.86 g of 1,3,4-thiadiazole-2,5-dithiol dipotassium salt obtained from Sigma Al-drich was dissolved in 300 g of deionized water and 25.8 g of zinc chloride was added. The reaction was stirred at 75°C under a nitrogen atmosphere for 4 hours, after which a white solid precipitated from the solution. The solid was filtered and washed to remove potassium chloride byproduct and dried in a vacuum oven. The product yield was 37.2 g.

[0047] Example 2. Synthesis of 5-(methylthio)-1,3,4-thiadiazole-2(3H)-thione using Van de Mark 1 The procedure was slightly modified. 56.1 g KOH and 900 g ethanol were added to a 3 L flask and the mixture was heated at 50 ° C for 2 hours. The reaction was cooled to 10 ° C in an ice water bath and 150.2 g 2,5-dimercapto-1,3,4-thiadiazole (DMTD) was added in batches over 20 minutes. The reaction mixture was heated at 60 ° C for 3 hours and then cooled to room temperature. 142 g methyl iodide was added at 15 ° C for 20 minutes and the mixture was heated to reflux (78 ° C) for 6 hours. About half of the reaction mixture was distilled off to remove the solvent and the remaining solution was cooled and then distributed between water and toluene in a separatory funnel. The toluene phase was collected, dried over anhydrous magnesium sulfate, and concentrated on a rotary evaporator to obtain the crude product. 13 C NMR showed that a mixture of monomethylated and dimethylated products was obtained. Recrystallization from reagent grade toluene gave 64 g of the final product, which was a 13:87 molar mixture of dimethylated DMTD and the desired monomethylated DMTD. (1.) Van de Mark, M. et al.: 5-Mercapto-1,3,4-Thiadiazole-2(3H)-thione: Synthesis and Structure of Alkylated Derivatives, J. Heterocyclic Chem., 2014, 51, p747.

[0048] Example 3. Synthesis of Zinc Bis-(2-Methylthio)-1,3,4-Thiadiazole-5-Thiolate - 22.8 g of crude 5-(methylthio)-1,3,4-thiadiazole-2(3H)-thione prepared in Example 2 was dissolved in 250 g of deionized water and 7.8 g of potassium hydroxide was added. The reaction was heated at 80°C for 4 hours under nitrogen atmosphere and cooled. In a separatory funnel, the aqueous solution was washed with two 75 mL portions of reagent grade toluene to remove dialkylated DMTD contaminants, collected and transferred to a 500 mL round bottom flask. 9.1 g of zinc chloride was added and the mixture was heated at 75°C under nitrogen for 4 hours. After cooling, the white precipitate was filtered, washed with deionized water, and dried in a vacuum oven to give 25.7 g.

[0049] Example 4. Synthesis of 2-isopentylthio-5-thiol-1,3,4-thiadiazole - 150.2 g of 2,5-dimercapto-1,3,4-thiadiazole and 500 mL of ethanol were added to a 2 L flask and 56.1 g of potassium hydroxide was added. The reaction was heated at 77 °C for 3 hours under nitrogen and cooled to room temperature. 151.05 g of isopentyl bromide was added and the mixture was heated at 77 °C for 6 hours. About 80% of the ethanol was distilled off. The reaction mixture was cooled and transferred to a 2 L separatory funnel containing 400 g of water and 600 mL of reagent grade toluene. After washing thoroughly with more water, the upper organic phase was collected, dried over anhydrous sodium sulfate, filtered, and vacuum stripped on a rotary evaporator to give 218 g of a low melting point solid. 13 C NMR showed that most of the monoalkylate was present along with some dialkylate. The solid was recrystallized from reagent grade toluene:methanol (80:20) wt. and dried in a vacuum oven. The yield of the final product was 135 g.

[0050] Example 5. Synthesis of 2-(2-amidoethylthio)-5-thiol-1,3,4-thiadiazole - 180.3 g of 2,5-dimercapto-1,3,4-thiadiazole and 0.4 g of sodium hydroxide were added to 900 g of deionized water in a 2 L flask. 85.3 g of acrylamide was added and the mixture was heated at 90°C for 12 hours. The insoluble product was collected by filtration using a fritted glass funnel and washed with 0.5 L of fresh deionized water and then dried in a vacuum oven. The yield of the final product was 259 g.

[0051] Using a procedure similar to Example 3, the corresponding zinc salts were prepared from Examples 4 and 5:

[0052] Example 6. Zinc bis-(2-isopentylthio)-1,3,4-thiadiazole-5-thiol

[0053] Example 7. Zinc bis-(2-(2-amidoethylthio)-1,3,4-thiadiazole-5-thiol

[0054] The following table provides the results of using 1M ZnSO 4 Galvanostatic cycling experiments of coin cells of several example Zn DMTD samples with aqueous electrolyte solution and Zn foil as anode.

[0055] Coin cell preparation: The powders of zinc DMTD and conductive carbon black (SuperP TM , purchased from Imerys) and polyvinylidene fluoride (PVDF) binder to prepare the electrode dry mixture. The dried electrode powder (about 8 mg-12 mg) was directly cast into the coin cell housing. The coin cell was assembled in air, where the cathode powder, 1 M ZnSO 4 Aqueous solution as electrolyte, Nafion TM and / or GFA as separator, and Zn foil as anode. Coin cells were assembled from bottom to top using materials purchased from Gelon: coin cell bottom, cathode powder, 50 μL electrolyte, Nafion TM and / or GFA separator, 50 μL electrolyte, Zn anode, stainless steel current collector, corrugated / conical gasket, coin cell top with gasket. Coin cells were crimped at 900 psi in a Gelon GN-CCM20 coin cell crimper and used for battery testing after a 2 hour rest period.

[0056] The assembled coin cells were subjected to galvanostatic cycling using an automated testing system with a lower voltage limit of 0.7 V (vs. Zn) and an upper voltage limit of 1.8 V (vs. Zn). The current of the galvanostatic measurement was calculated based on the theoretical specific capacity of each compound.

[0057] Theoretical capacity = F / (3600*MW); F is the Faraday constant, MW is the molecular weight

[0058] C rate: refers to the current used for constant current cycling.

[0059] The maximum capacity is the maximum capacity achieved / theoretical capacity. [The maximum capacity achieved] is the capacity achieved when the discharge reaches the low cut-off voltage.

[0060] The decay / cycle was estimated based on capacity decay (in mAh / g) / cycle = (capacity of first cycle - capacity of last cycle) / (number of cycles * capacity of first cycle).

[0061] The voltage gap is the voltage difference between the charging plateau and the discharging plateau.

[0062] When the battery is charged or discharged at a stable voltage, it is called the charging plateau and discharging plateau respectively.

[0063]

[0064] Each document mentioned above is incorporated herein by reference, including any previous application claiming its priority, whether or not specifically listed above. The mention of any document is not to admit that the document is not qualified to become the prior art or constitute the general knowledge of the technician in any jurisdiction. Unless in the embodiment or otherwise clearly pointed out, all numerical values ​​of the amount of substance, reaction conditions, molecular weight, carbon number, etc. in this specification sheet should be understood to be modified by the word "about". It should be understood that the upper and lower limits of the amount, range and ratio described herein can be independently combined. Similarly, the scope and amount of every kind of key element of the present invention can be used together with the scope or amount of any other key element.

[0065] As used herein, the transitional term "comprising," which is synonymous with "comprising," "containing," or "characterized by," is inclusive or open-ended and does not exclude additional, unrecited elements or method steps. However, in each use of "comprising" herein, it is intended that the term also encompasses the phrases "consisting essentially of" and "consisting of" as alternative embodiments, wherein "consisting of" excludes any element or step not specified, and "consisting essentially of" permits the inclusion of additional, unrecited elements or steps that do not materially affect the essential or basic and novel characteristics of the composition or method under consideration.

[0066] Although certain representative embodiments and details have been shown for the purpose of illustrating the present invention, it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the scope of the present invention. In this regard, the scope of the present invention is limited only by the following claims.

[0067] A DMTD derivative of the following formula

[0068]

[0069] wherein X is a negative charge or H, or a hydrocarbon group of 1 to 10 carbon atoms. The DMTD derivative according to the preceding sentence, wherein X is a hydrocarbon group of 1 to 8 carbon atoms. The DMTD derivative according to the preceding sentence, wherein X is a hydrocarbon group of 1 to 6 carbon atoms.

[0070] The DMTD derivative according to the preceding paragraph, wherein the hydrocarbyl group comprises an alkyl group or an amide group.

[0071] A DMTD derivative according to any sentence of any preceding paragraph, wherein the derivative has the formula:

[0072]

[0073] A DMTD derivative according to any sentence of any preceding paragraph, wherein the derivative has the formula:

[0074]

[0075] A DMTD derivative according to any sentence of any preceding paragraph, wherein the derivative has the formula:

[0076]

[0077] A DMTD derivative according to any sentence of any preceding paragraph, wherein the derivative has the formula:

[0078]

[0079] A DMTD derivative according to any sentence of any preceding paragraph, wherein the derivative has the formula:

[0080]

[0081] A DMTD derivative according to any sentence of any preceding paragraph, wherein the derivative has the formula:

[0082]

[0083] A zinc electrode comprising A) a DMTD derivative according to any sentence of any preceding paragraph, B) a polymer binder, and C) at least one conductive material.

[0084] The zinc electrode according to any preceding paragraph, wherein the DMTD or a derivative thereof is present in about 40 wt % to 80 wt % of the electrode composition.

[0085] The zinc electrode according to any preceding paragraph, wherein the DMTD or a derivative thereof is present in about 45 wt % to 75 wt % of the electrode composition.

[0086] The zinc electrode according to any preceding paragraph sentence, wherein the DMTD or a derivative thereof is present in about 50 wt % to 70 wt % of the electrode composition.

[0087] The zinc electrode according to any preceding paragraph, wherein the DMTD or a derivative thereof is present in about 55 wt % to 65 wt % of the electrode composition.

[0088] The zinc electrode according to any sentence of any preceding paragraph, wherein the polymer binder is present at about 1 wt % to 20 wt % of the electrode composition.

[0089] The zinc electrode according to any sentence of any preceding paragraph, wherein the polymer binder is present at about 2.5 wt % to 15 wt % of the electrode composition.

[0090] The zinc electrode according to any sentence of any preceding paragraph, wherein the polymer binder is present at about 5% to 10% by weight of the electrode composition.

[0091] The zinc electrode according to any sentence of any preceding paragraph, wherein the polymer binder is PVDF, styrene-butadiene rubber.

[0092] The zinc electrode according to any sentence of any preceding paragraph, wherein the conductive material is present at about 10% to 40% by weight of the electrode composition.

[0093] The zinc electrode according to any sentence of any preceding paragraph, wherein the conductive material is present at about 15% to 35% by weight of the electrode composition.

[0094] The zinc electrode according to any sentence of any preceding paragraph, wherein the conductive material is present at about 20% to 30% by weight of the electrode composition.

[0095] A zinc electrode according to any sentence of any preceding paragraph, wherein the conductive material is conductive carbon black.

[0096] A zinc ion battery system comprising A) a zinc anode, B) an electrolyte comprising a zinc salt solution, and C) a zinc electrode according to any sentence of any preceding paragraph.

[0097] A zinc ion battery according to any sentence of any preceding paragraph, wherein the zinc salt of the electrolyte comprises zinc sulfate (ZnSO 4 ), zinc trifluoromethanesulfonate (Zn(OTf)), and at least one of a combination thereof.

[0098] A zinc ion battery according to any sentence of any preceding paragraph, wherein the concentration of the zinc salt in the electrolyte is 0.05M to 5M.

[0099] A zinc ion battery according to any sentence of any preceding paragraph, wherein the concentration of the zinc salt in the electrolyte is 0.25M to 4M.

[0100] A zinc ion battery according to any sentence of any preceding paragraph, wherein the concentration of the zinc salt in the electrolyte is 0.5M to 3.5M.

[0101] A zinc ion battery according to any sentence of any preceding paragraph, wherein the concentration of the zinc salt in the electrolyte is 0.75M to 3M.

Claims

1. A zinc electrode comprising A) a DMTD derivative of the following formula wherein X is a negative charge or H, or an alkyl group of 1 to 6 carbon atoms, B) a polymer binder and C) at least one conductive material.

2. The zinc electrode of claim 1, wherein the DMTD derivative is present in 40 to 80 wt% of the electrode composition.

3. The zinc electrode of claim 1, wherein the polymer binder is present in an amount of 1 wt% to 20 wt% of the electrode composition.

4. The zinc electrode of claim 2, wherein the polymer binder is present in an amount of 1 wt% to 20 wt% of the electrode composition.

5. The zinc electrode according to claim 1, wherein the polymer binder is PVDF, styrene-butadiene rubber.

6. The zinc electrode according to claim 2, wherein the polymer binder is PVDF, styrene-butadiene rubber.

7. The zinc electrode according to claim 3, wherein the polymer binder is PVDF, styrene-butadiene rubber.

8. The zinc electrode according to claim 4, wherein the polymer binder is PVDF, styrene-butadiene rubber.

9. The zinc electrode of any one of claims 1-8, wherein the conductive material is present in 10 to 40 weight percent of the electrode composition.

10. The zinc electrode according to any one of claims 1 to 8, wherein the conductive material is carbon black.

11. The zinc electrode of claim 9, wherein the conductive material is carbon black.

12. A zinc ion battery system comprising A) a zinc anode, B) an electrolyte comprising a zinc salt solution, and C) a zinc electrode according to any one of claims 1 to 11.

13. The zinc ion battery system of claim 12, wherein the zinc salt of the electrolyte comprises at least one of zinc sulfate (ZnSO4), zinc trifluoromethanesulfonate (Zn(OTf)2), and combinations thereof.

14. The zinc ion battery system of claim 12 or 13, wherein the concentration of the zinc salt in the electrolyte is 0.05 M to 5 M.

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