阅读说明：本技术 具有锌金属负电极和温和水性电解质的二次电化学电池及其方法 (Secondary electrochemical cell having zinc metal negative electrode and mild aqueous electrolyte and method therefor ) 是由 B.D.亚当斯 J.H.安 R.D.布朗 R.D.克拉克 M.B.库西尼尔 J.P.S.李 于 2018-11-19 设计创作，主要内容包括：提供了用于储存和递送电能的二次电化学电池及形成其的方法。所述二次电化学电池包括：薄膜锌金属负电极,其包含负电极集流体和施加到所述负电极集流体的锌金属层；薄膜正电极,其包含正电极集流体和施加到所述正电极集流体的活性材料层,其中所述活性材料层与Zn2+阳离子可逆地进行电化学反应；水性电解质,其将所述负电极离子耦合到所述正电极；以及薄隔板,其设置在所述负电极和所述正电极之间,其中所述隔板被所述水性电解质润湿。(Secondary electrochemical cells for storing and delivering electrical energy and methods of forming the same are provided. The secondary electrochemical cell includes: a thin film zinc metal negative electrode comprising a negative electrode current collector and a zinc metal layer applied to the negative electrode current collector; a thin film positive electrode comprising a positive electrode current collector and an active material layer applied to said positive electrode current collector, wherein said active material layer reversibly electrochemically reacts with Zn2+ cations; an aqueous electrolyte ionically coupling the negative electrode to the positive electrode; and a thin separator disposed between the negative electrode and the positive electrode, wherein the separator is wetted by the aqueous electrolyte.)

1. A secondary electrochemical cell for storing and delivering electrical energy, the secondary electrochemical cell comprising:

a thin film zinc metal negative electrode comprising:

a negative electrode current collector; and

a zinc metal layer applied to the negative electrode current collector;

a thin film positive electrode comprising:

a positive electrode current collector; and

an active material layer applied to the positive electrode current collector;

wherein the active material layer is formed with Zn²⁺The cation reversibly carries out electrochemical reaction;

an aqueous electrolyte ionically coupling the negative electrode to the positive electrode;

a thin separator disposed between the negative electrode and the positive electrode, wherein the separator is wetted by the aqueous electrolyte.

2. The secondary electrochemical cell of claim 1 wherein the area capacity of the zinc metal layer is greater than the area capacity of the positive electrode.

3. The secondary electrochemical cell of claim 2, wherein the thin film zinc metal negative electrode has a first face and a second face, and wherein the zinc metal layer has an area capacity of greater than or equal to 1mAh/cm on each of the first face and the second face of the negative electrode²。

4. The secondary electrochemical cell of any one of claims 1 to 3, wherein the thickness of the negative electrode current collector is less than or equal to 50 μm.

5. The secondary electrochemical cell of any one of claims 1-4, wherein the negative electrode current collector comprises a conductive metal foil.

6. The secondary electrochemical cell of claim 5, wherein the zinc metal layer is deposited onto the negative electrode current collector using a slurry casting process.

7. The secondary electrochemical cell of claim 5, wherein the zinc metal layer is deposited onto the negative electrode current collector using a dough rolling process, the dough comprising the zinc metal layer.

8. The secondary electrochemical cell of claim 1, wherein the aqueous electrolyte comprises a zinc salt dissolved in water.

9. The secondary electrochemical cell of claim 8, wherein the aqueous electrolyte comprises zinc ions in a range of 0.001 molar to 10 molar.

10. The secondary electrochemical cell of claim 8, wherein the aqueous electrolyte comprises zinc ions in the range of 0.1 to 4 moles.

11. The secondary electrochemical cell of any one of claims 8 to 10 wherein the zinc salt is selected from the group consisting of zinc sulfate, zinc acetate, zinc citrate, zinc iodide, zinc chloride, zinc perchlorate, zinc bis (trifluoromethanesulfonyl) imide, zinc nitrate, zinc phosphate, zinc trifluoromethanesulfonate, zinc tetrafluoroborate and zinc bromide.

12. The secondary electrochemical cell of claim 1 or 8 wherein the aqueous electrolyte has a pH between 4 and 6.

13. The secondary electrochemical cell of claim 1 or 8, wherein the aqueous electrolyte comprises a gelling agent for increasing the viscosity of the aqueous electrolyte.

14. The secondary electrochemical cell of claim 13, wherein the gelling agent is present in an amount between 0.01-20% by weight of the aqueous electrolyte.

15. The secondary electrochemical cell of claim 13 wherein the gelling agent is selected from the group consisting of xanthan gum, cellulose nanocrystals, fumed silica, colloidal silica, carboxymethylcellulose, gelatin, alginates, agar, pectin, talc, sulfonates, casein, collagen, albumin, silicones, polyacrylic acid (or polyacrylate), and polyvinyl alcohol.

16. The secondary electrochemical cell of claim 1, wherein the thickness of the thin separator is less than or equal to 200 μ ι η.

17. The secondary electrochemical cell of claim 1 or 16, wherein the thin separator comprises an electrically insulating woven or nonwoven material wetted by the aqueous electrolyte.

18. The secondary electrochemical cell of any one of claims 1, 16 and 17, wherein the thin separator comprises ceramic or glass particles embedded in a polymer matrix of textile fibers.

19. The secondary electrochemical cell of any of claims 1, 16, and 17, wherein the thin separator comprises ceramic particles embedded in a polymer matrix of textile fibers.

20. The secondary electrochemical cell of any of claims 1, 16, and 17, wherein the thin separator comprises glass particles embedded in a polymer matrix of textile fibers.

21. The secondary electrochemical cell of claim 18 or 19, wherein the textile fibers are coated with the ceramic particles.

22. The secondary electrochemical cell of claim 18 or 20, wherein the textile fibers are coated with the glass particles.

23. The secondary electrochemical cell of any of claims 1, 16, 17, and 18, wherein the thin separator is microporous and has an average pore size of less than or equal to 1 μ ι η.

24. The secondary electrochemical cell of claim 1, wherein the thin film positive electrode has a first face and a second face, and wherein on each of the first face and the second face of the positive electrode, the storage capacity per electrode area is 1mAh/cm²-10 mAh/cm²In the meantime.

25. The secondary electrochemical cell of claim 1, wherein the positive electrode current collector comprises a metal substrate.

26. The secondary electrochemical cell of claim 1, wherein the active material layer comprises a mixture of an electrochemically active material, a conductive additive, and a binder.

27. The secondary electrochemical cell of claim 1, wherein the positive electrode current collector comprises a metal foil.

28. The secondary electrochemical cell of claim 1 or 27, wherein the thickness of the positive electrode current collector is less than or equal to 50 μ ι η.

29. The secondary electrochemical cell of any one of claims 1, 27, and 28, wherein the active material layer is deposited onto the positive electrode current collector using a slurry casting process.

30. The secondary electrochemical cell of any one of claims 1, 27, and 28, wherein the active material layer is deposited onto the positive electrode current collector using a dough rolling process, the dough comprising the active material layer.

31. A method of forming a secondary electrochemical cell, the method comprising:

providing a thin film zinc metal negative electrode and a thin film positive electrode, wherein:

the thin film zinc metal negative electrode comprises:

a negative electrode current collector; and

a zinc metal layer applied to the negative electrode current collector;

the thin film positive electrode comprises:

a positive electrode current collector; and

an active material layer applied to the positive electrode current collector;

wherein the active material layer is formed with Zn²⁺The cation reversibly carries out electrochemical reaction;

ionically coupling the negative electrode to the positive electrode via an aqueous electrolyte; and

disposing a thin separator between the negative electrode and the physical electrode, wherein the thin separator is wetted by the aqueous electrolyte.

32. The method of claim 31, wherein the area capacity of the zinc metal layer is greater than or equal to the area capacity of the positive electrode.

33. The method of claim 31 or 32, wherein the thin film zinc metal negative electrode has a first face and a second face, and wherein the zinc metal layer has an area capacity of greater than or equal to 1mAh/cm on each of the first face and the second face of the negative electrode²。

34. The method of any one of claims 31-33, wherein the thickness of the negative electrode current collector is less than or equal to 50 μ ι η.

35. The method of any one of claims 31-34, wherein the negative electrode current collector comprises a conductive metal foil.

36. The method of claim 35, wherein the zinc metal layer is deposited onto the negative electrode current collector using a slurry casting process.

37. The method of claim 35, wherein the zinc metal layer is deposited onto the negative electrode current collector using a dough rolling process, the dough comprising the zinc metal layer.

38. The method of claim 31, wherein the aqueous electrolyte comprises a zinc salt dissolved in water.

39. The method of claim 38, wherein the aqueous electrolyte comprises zinc ions in a range of 0.001 molar to 10 molar.

40. The method of claim 38, wherein the aqueous electrolyte comprises zinc ions in the range of 0.1 to 4 moles.

41. The method of any one of claims 38 to 40, wherein the zinc salt is selected from the group consisting of zinc sulfate, zinc acetate, zinc citrate, zinc iodide, zinc chloride, zinc perchlorate, zinc bis (trifluoromethanesulfonyl) imide, zinc nitrate, zinc phosphate, zinc trifluoromethanesulfonate, zinc tetrafluoroborate and zinc bromide.

42. The method of claim 31 or 38, wherein the aqueous electrolyte has a pH between 4 and 6.

43. The method of claim 31 or 38, wherein the aqueous electrolyte comprises a gelling agent for increasing the viscosity of the aqueous electrolyte.

44. The method of claim 43, wherein the gelling agent is present in an amount between 0.01% -20% by weight of the aqueous electrolyte.

45. The method of claim 43, wherein the gelling agent is selected from the group consisting of xanthan gum, cellulose nanocrystals, fumed silica, colloidal silica, carboxymethylcellulose, gelatin, alginates, agar, pectin, talc, sulfonates, casein, collagen, albumin, silicones, polyacrylic acid, polyacrylates) and polyvinyl alcohol.

46. The method of claim 31, wherein the thin separator has a thickness of less than or equal to 200 μ ι η.

47. The method of claim 31 or 46, wherein the thin separator comprises an electrically insulating woven or nonwoven material wetted by the aqueous electrolyte.

48. The method of any one of claims 31, 46 and 47, wherein the thin separator comprises ceramic or glass particles embedded in a polymer matrix of textile fibers.

49. The method of any one of claims 31, 46 and 47, wherein the thin separator comprises ceramic particles embedded in a polymer matrix of textile fibers.

50. The method of any one of claims 31, 46, and 47, wherein the thin separator comprises glass particles embedded in a polymer matrix of textile fibers.

51. The method of claim 48 or 49, wherein said textile fibers are coated with said ceramic particles.

52. The method of claim 48 or 50, wherein the textile fibers are coated with the glass particles.

53. The method of any one of claims 31, 46, 47, and 48, wherein the thin separator is microporous and has an average pore size of less than or equal to 1 μm.

54. The method of claim 31, wherein the thin film positive electrode has a first side and a second side, and wherein the storage capacity per electrode area on each of the first side and the second side of the positive electrode is 1mAh/cm²-10mAh/cm²In the meantime.

55. The method of claim 31, wherein the positive electrode current collector comprises a metal substrate.

56. The method of claim 31, wherein the active material layer comprises a mixture of an electrochemically active material, a conductive additive, and a binder.

57. The method of claim 31, wherein the positive electrode current collector comprises a metal foil.

58. The method of claim 31 or 57, wherein the thickness of the positive electrode current collector is less than or equal to 50 μm.

59. The method of any one of claims 31, 57, and 58, wherein the active material layer is deposited onto the positive electrode current collector using a slurry casting process.

60. The method of any one of claims 31, 57, and 58, wherein the active material layer is deposited onto the positive electrode current collector using a dough rolling process, the dough comprising the active metal layer.

61. The method of claim 31, further comprising controlling the pH of the aqueous electrolyte to be between 4 and 6.

Technical Field

The following generally relates to secondary electrochemical cells, and more particularly, to secondary electrochemical cells using metallic zinc as the negative electrode.

Introduction to

Metallic zinc negative electrodes are used in many primary (non-rechargeable) and secondary (rechargeable) aqueous battery types. Zinc is inexpensive, non-toxic, has a low redox potential (-0.76V relative to standard hydrogen electrodes) compared to other negative electrode materials used in aqueous batteries, and is stable in water due to the high overpotential for hydrogen evolution.

Electrochemical cells using zinc metal have been used in commercial applications. Several conventional and modern types of batteries using zinc metal electrodes are listed in fig. 1, along with internal battery chemistries in the form of standard battery symbols. Basicity (Zn | MnO)₂) Zinc-air (Zn O)₂) And Ni — Zn (Zn NiOOH) are being commercialized as rechargeable batteries. Each of these uses an alkaline electrolyte, most commonly based on high concentrations of NaOH or KOH. The recharging capability of these batteries is limited due to the tendency of zinc to form dendrites in the alkaline electrolyte during battery recharging (Zn plating). These dendrites can grow from the negative electrode toPositive electrode and causes the battery to experience an internal short circuit.

Table 1. zinc cell type.

A disadvantage and challenge of secondary batteries using zinc negative electrodes is the low coulombic efficiency of dendritic or moss deposit formation and plating/stripping cycles. Uncontrolled deposition of zinc can form accumulations during repeated cycling and cause premature cell failure through internal short circuits. Low coulombic efficiency limits cycle life by consuming active zinc metal through side reactions or forming inactive "dead" zinc within the cell. In general, the higher coulombic efficiency of zinc metal stripping/plating allows for a lower excess of zinc in the negative electrode to achieve the same number of cycles in the cell.

Zinc electrodes in alkaline electrolytes are particularly prone to dendritic zinc formation and low coulombic efficiencies (typically < 85%). Some battery chemistries using zinc metal electrodes may utilize neutral or acidic electrolytes, e.g., relying on Zn at the positive electrode²⁺The insertion/extraction zinc ion system of (1). Not dissolution/precipitation reactions at the zinc electrode in alkaline electrolytes (Zn + 4 OH)^-↔Zn(OH)₄ ^2-+ 2e^-And Zn (OH)₄ ^2-↔ZnO + 2OH- + H₂O), reaction mechanism in acidic electrolyte (Zn ↔ Zn)²⁺+2e^-) Insulating zinc oxide is not involved. This advantage results in a much higher coulombic efficiency, typically greater than 95%. However, strongly acidic electrolytes pose additional challenges, such as enhanced hydrogen evolution during battery charging (HER: 2H)⁺+ e^-→H₂) And corrosion of the battery case, current collectors, and dissolution of active battery materials.

U.S. patent No. 6,187,475 to Ahanyang Seung-Mo Oh and Kunpo Sa-Heum Kim describes a zinc ion battery using a mild, near neutral pH aqueous electrolyte. However, the battery can only achieve 120 cycles.

Accordingly, there is a need for secondary electrochemical cells having zinc metal negative electrodes that overcome at least some of the drawbacks of conventional zinc and non-zinc secondary cells.

Brief description of the drawings

According to some embodiments, there is a secondary electrochemical cell for storing and delivering electrical energy, the secondary electrochemical cell comprising: a thin film zinc metal negative electrode having a negative electrode current collector and a zinc metal layer applied to the negative electrode current collector; a thin film positive electrode having a positive electrode current collector and an active material layer applied to the positive electrode current collector, wherein the active material layer is in contact with Zn²⁺The cation reversibly carries out electrochemical reaction; an aqueous electrolyte ionically coupling the negative electrode to the positive electrode; and a thin separator disposed between the negative electrode and the positive electrode, wherein the separator is wetted by the aqueous electrolyte.

In one aspect, the area capacity of the zinc metal layer is greater than the area capacity of the positive electrode.

In another aspect, the thin film zinc metal negative electrode has a first face and a second face, and the zinc metal layer has an area capacity greater than or equal to 1mAh/cm on each of the first and second faces of the negative electrode²。

In another aspect, the aqueous electrolyte has a pH between 4 and 6.

In another aspect, the aqueous electrolyte comprises a gelling agent for increasing the viscosity of the aqueous electrolyte.

In another aspect, the thickness of the thin separator is less than or equal to 200 μm.

In another aspect, the thin separator comprises an electrically insulating woven or nonwoven material wetted by the aqueous electrolyte.

In a further aspect, the thin separator comprises ceramic or glass particles embedded in a polymer matrix of textile fibers.

In another aspect, the thin-film positive electrode has a first side and a second side, and whereinA storage capacity per electrode area on each of the first and second sides of the positive electrode of 1mAh/cm²-10 mAh/cm²In the meantime.

According to some embodiments, there is a method of forming a secondary electrochemical cell, the method comprising: providing a thin film zinc metal negative electrode comprising a negative electrode current collector and a zinc metal layer applied to the negative electrode current collector and a thin film positive electrode comprising a positive electrode current collector and an active material layer applied to the positive electrode current collector; wherein the active material layer is formed with Zn²⁺The cation reversibly carries out electrochemical reaction; ionically coupling the negative electrode to the positive electrode via an aqueous electrolyte; and disposing a thin separator between the negative electrode and the physical electrode, wherein the thin separator is wetted by the aqueous electrolyte.

In one aspect, the area capacity of the zinc metal layer is greater than the area capacity of the positive electrode.

In another aspect, the thin film zinc metal negative electrode has a first face and a second face, and the zinc metal layer has an area capacity greater than or equal to 1mAh/cm on each of the first and second faces of the negative electrode²。

In another aspect, the aqueous electrolyte has a pH between 4 and 6.

In another aspect, the aqueous electrolyte includes a gelling agent for increasing the viscosity of the aqueous electrolyte.

In another aspect, the thickness of the thin separator is less than or equal to 200 μm.

In another aspect, the thin separator comprises an electrically insulating woven or nonwoven material wetted by the aqueous electrolyte.

In a further aspect, the thin separator comprises ceramic or glass particles embedded in a polymer matrix of textile fibers.

In another aspect, the thin-film positive electrode has a first side and a second side, and wherein on each of the first side and the second side of the positive electrode, a reservoir area per electrode areaThe storage capacity is 1mAh/cm²-10 mAh/cm²In the meantime.

Other aspects and features will become apparent to those ordinarily skilled in the art upon review of the following description of certain exemplary embodiments.

Brief description of the drawings

The figures included herein are intended to illustrate various examples of articles, methods, and apparatus of the present description. In the drawings:

fig. 1 is a side view of a zinc metal secondary battery according to an embodiment;

fig. 2A is a cross-sectional view of a first embodiment of a cell of the zinc metal secondary battery of fig. 1;

fig. 2B is a cross-sectional view of a second embodiment of the cell of the zinc metal secondary battery of fig. 1;

fig. 2C is a cross-sectional view of a third embodiment of the cell of the zinc metal secondary cell of fig. 1;

fig. 3 is a graph illustrating cycle life of zinc metal before failure due to internal short circuits in a Zn Ti battery, in accordance with an embodiment;

fig. 4 is a graph illustrating the results of Zn | Zn symmetric cells used to test different electrolyte gel formers for electroplating and stripping of zinc metal electrodes, according to an example;

FIG. 5 illustrates 1M ZnSO dissolved in an aqueous electrolyte according to an example₄+ 0.1M MnSO₄0.6mA/cm²A graph of a first cycle voltage profile for both the cycled thin-film electrode and the thick electrode;

fig. 6 is a graph illustrating the cycle performance of the two Zn | | | EMD batteries of fig. 5 by their area capacity (mAh/cm)²) Expressed as a function of cycle number;

FIG. 7 shows a zinc metal negative electrode (Zn foil = 30. mu.M) immersed in 1M ZnSO₄Paper separator (160 μ M) in water electrolyte and Zn on matte Ni foil current collector (15 μ M)_0.25V₂O₅.nH₂A schematic representation of an exemplary first cycle of a cell prepared with a positive electrode made with an O-active coating;

fig. 8 is a graphical representation of an exemplary first cycle of a cell having a zinc negative electrode.

Detailed Description

Various apparatuses or methods will be described below to provide examples of each of the claimed embodiments. The embodiments described below do not limit any claimed embodiments, and any claimed embodiments may cover methods or apparatus different from those described below. The claimed embodiments are not limited to a device or method having all the features of any one device or method described below, or to features in common with a plurality or all of the devices described below.

In order to ensure long cycle life, secondary batteries using zinc metal negative electrodes require high reversibility of the zinc stripping and plating cycles. In addition, in order to maximize the actual gravimetric and volumetric energy densities of the secondary battery, the amount of active material should be maximized while minimizing the amount of inactive components. For example, the area capacity of the positive electrode matches the capacity of the zinc negative electrode, and the excess of zinc metal should be minimized. Excess zinc metal is considered to be a non-reactive component. Other inactive components include negative and positive electrode current collectors and separators.

The present invention relates generally to improving the cycle life of secondary electrochemical cells having zinc metal negative electrodes in mild (pH from about 4 to about 6) aqueous electrolytes. Any one or more of the choice of separator material, the thickness of the separator, the use of gelled electrolyte, and the limitation of the amount of zinc plated and exfoliated during each charge/discharge cycle can extend the cycle life of the secondary electrochemical cell. As used herein, "cycle life" refers to the number of times a secondary battery can be discharged and charged before the secondary electrochemical cell stores 80% of its initial capacity.

The term "about" as used herein, when used in reference to a pH value, means +/-0.5 of a given pH value, unless otherwise specified. When the term "about" is used in reference to a pH range, it is understood that the foregoing definition of "about" applies to both the lower and upper limits of the range.

The term "about" as used herein, when used in reference to molar concentration ("moles") values, means a molar value +/-0.1 moles, unless otherwise specified. When the term "about" is used in reference to a molar range, it is understood that the foregoing definition of "about" applies to both the lower and upper limits of that range.

As used herein, unless otherwise specified, the term "between," when used in reference to a numerical range such as a molar range or a pH range, means a range including a lower value and an upper value. For example, a pH range of "between 4 and 6" is considered to include pH values of 4.0 and 6.0.

The present disclosure describes zinc ion battery designs that are easy to manufacture and/or extend the cycle life of zinc ion batteries to hundreds or thousands of cycles. The design of zinc ion batteries can affect the plating and stripping of zinc during battery cycling and thus affect cycle life.

For each of the negative and positive electrodes, the use of a metal foil as a current collector with a relatively thin coating of electrochemically active material can provide an easily manufactured zinc-ion battery design. Thin film coatings may allow for the manufacture of electrodes using methods similar to those employed in the manufacture of lithium ion battery electrodes. In addition, the electrodes described herein may be flexible enough to be assembled into the battery form typically employed in lithium ion batteries.

Referring now to fig. 1, a secondary electrochemical cell 100 according to an embodiment is shown. Battery 100 may be used to store and deliver electrical energy.

The secondary battery 100 includes a thin film zinc metal negative electrode 10, an aqueous electrolyte, a thin film positive electrode 20, and a thin separator 3. The battery 100 may be a thin film electrode stack configuration.

The negative electrode 10 is a thin film zinc metal electrode. The thickness (thickness value) of the thin film zinc metal electrode may be on the order of microns. Negative electrode 10 includes a first face 11 and a second face 12. The negative electrode 10 includes a zinc metal layer 2. The area capacity of the zinc metal layer 2 may be greater than the area capacity of the positive electrode 20. The area capacity of the zinc metal layer 2 may be greater than 1mAh/cm on each side 11, 12 of the negative electrode 10²。

The negative electrode 10 includes a current collector 1 for collecting current. The current collector 1 may have a thickness of less than 50 μm. Current collector 1 includes a first face 13 and a second face 14. The zinc metal layer 2 adheres to the first 13 and second 14 faces of the current collector 1. The current collector 1 may be a conductive metal foil.

In one embodiment, the negative electrode 10 may be formed on a metal foil substrate (current collector 1) using slurry casting or rolling of a paste or dough containing zinc metal.

Positive electrode 20 is a thin film positive electrode. The thickness of the thin film positive electrode may be on the order of microns. Positive electrode 20 includes a first face 15 and a second face 16.

Positive electrode 20 and Zn²⁺The cation reacts reversibly. The positive electrode 20 includes Zn in the electrolyte in a reversible manner²⁺An active material 4 where electrochemical reaction occurs. By "reversible" is meant the ability to recover at least 90% of the charge stored in the material when battery 100 is charged. The amount of active material 4 on the positive electrode can be limited such that the storage capacity per electrode area on each face 15, 16 of the positive electrode 20 is 1mAh/cm²-10 mAh/cm²In the meantime.

Positive electrode 20 includes a current collector 5 for collecting current. Current collector 5 comprises a metal substrate. Current collector 5 includes a first face 17 and a second face 18. Current collector 5 may be coated on first side 17 and second side 18 with a mixture including an electrochemically active material, a conductive additive, and a binder. Current collector 5 of positive electrode 20 may be a metal foil. The current collector 5 may be less than 50 μm thick.

In one embodiment, the positive electrode 20 may be formed by casting or rolling a slurry containing a paste or dough of the active material 4 on a metal foil substrate (current collector 5).

The aqueous electrolyte ionically couples the negative electrode 10 to the positive electrode 20. The pH of the electrolyte may be between about 4 and 6.

The electrolyte may include a zinc salt dissolved in water. The zinc salt may be dissolved such that zinc ions are present in the electrolyte in a range of about 0.001 molar to 10 molar. The zinc salt may be dissolved such that zinc ions are present in the electrolyte in a range of about 0.1 molar to about 4 molar. The zinc salt may be selected from zinc salts including zinc sulfate, zinc acetate, zinc citrate, zinc iodide, zinc chloride, zinc perchlorate, zinc bis (trifluoromethanesulfonyl) imide, zinc nitrate, zinc phosphate, zinc trifluoromethanesulfonate, zinc tetrafluoroborate and zinc bromide.

The electrolyte may include a gelling agent. The gelling agent and the gel forming agent are gelling agents or thickeners that increase the viscosity of the aqueous solution. The gelling agent may be present in the electrolyte in an amount between 0.01% and 20% by weight of the electrolyte. The gelling agent may be selected from gelling agents comprising: xanthan gum, cellulose nanocrystals, fumed silica, colloidal silica, carboxymethylcellulose, gelatin, alginates, agar, pectin, talc, sulfonates, casein, collagen, albumin, silicones, polyacrylic acid (or polyacrylate), and polyvinyl alcohol.

The separator 3 is wetted with the electrolyte. The separator 3 may be soaked with an electrolyte. The separator 3 is located in the battery 100 such that the separator 3 prevents the negative electrode 10 and the positive electrode 20 from physically contacting each other. A separator may be disposed between negative electrode 10 and positive electrode 20. The separator 3 is a thin separator. The thickness of the thin separator may be on the order of microns. The separator 3 may be less than 200 μm thick.

The separator 3 may include a woven or nonwoven material wetted with an electrolyte. The woven or nonwoven material may be electrically insulating.

The separator 3 may comprise particles embedded in a polymer matrix of textile fibers. In one embodiment, the particles are ceramic. In another embodiment, the particles are glass. The fibers of the separator 3 may be coated with ceramic or glass.

The separator 3 may be microporous. The microporous separator may have an average pore size of less than 1 μm.

Battery 100 may be manufactured using standard methods used in lithium ion battery manufacturing. For example, the battery 100 may be manufactured using roll-to-roll electrode coating on a metal foil current collector, spiral winding of a transparent jelly roll, electrode stacking, winding, and compression of the transparent jelly roll to produce prismatic, pouch-shaped, or cylindrical batteries, and the like.

The secondary electrochemical cell 100 can be easily manufactured. The use of metal foils as the negative electrode current collector 1 and the positive electrode current collector 5 having relatively thin coatings of electrochemically active materials (e.g., the zinc metal layer 2, the active material layer 4) facilitates the ease of manufacture of the secondary battery 100. The thin film coating allows the electrodes 10, 20 to be fabricated using methods similar to those employed in the fabrication of lithium ion battery electrodes. In addition, the electrodes 10, 20 are flexible enough to be assembled into the battery form typically employed in lithium ion batteries.

The secondary electrochemical cell 100 may have an extended cycle life as compared to conventional zinc secondary cells. Extended cycle life can reach hundreds or thousands of cycles. Secondary electrochemical cell 100 includes several design features that can have a positive impact on the plating and stripping of zinc during cell cycling, and thus on cycle life.

In one embodiment, battery 100 comprises a thin film electrode stack configuration in which negative electrode 10 comprises a current collector 1 coated with a zinc metal layer 2 on both sides, a separator 3 soaked in an electrolyte and preventing negative electrode 10 and positive electrode 20 from contacting each other, and a positive electrode 20 comprising an active layer 4 coated on both sides of a current collector 5.

Battery 100 may be particularly advantageous. Battery 100 may incorporate a number of design features to extend the cycle life of battery 100. Battery 100 may have an improved cycle life over conventional zinc-ion batteries. In some cases, the battery 100 may have a cycle life of hundreds or thousands of cycles. Battery 100 may incorporate a number of design features to facilitate ease of manufacture.

Referring now to fig. 2, there is shown a cross-sectional view of a number of possible battery forms 200 of a zinc metal secondary battery (e.g., the secondary battery 100 of fig. 1) according to embodiments.

Each of the battery forms/constructions 200 includes a plurality of layers. The multiple layers may be stacked or rolled. The layers include a negative electrode 10, a positive electrode 20, and a separator 3. The separator 3 is located or disposed between the negative electrode 10 and the positive electrode 20.

Fig. 2A shows a cylindrical battery form 200a according to one embodiment. In cylindrical cell form 200a, electrodes 10, 20 are spirally wound into a "transparent jelly roll".

Fig. 2B shows a prismatic battery form 200B according to one embodiment. Prismatic cell form 200b comprises a rigid housing in which the electrodes 10, 20 are rolled and compressed into a "flat transparent jelly roll".

Fig. 2C shows a pouch-shaped battery form 200C according to one embodiment. The pouch-shaped battery form 200c includes electrodes 10, 20 in a stacked configuration. The electrodes 10, 20 may be cut into pieces and stacked. It should be noted that both the prismatic battery form 200b and the pouch-shaped battery form 200c may contain wound (rolled) electrodes or stacks.

In some cases, the cycle life of a secondary battery (e.g., secondary battery 100 of fig. 1) can be extended by limiting the area capacity of the circulating zinc.

Referring now to fig. 3, there is shown a graph 300 illustrating the cycle life of zinc metal prior to failure due to internal short circuits in a Zn Ti cell. When the stripping capacity exceeds the plating capacity, this failure mode is marked by overcharging. In these cells, zinc was present at 5 mA/cm²Plating onto Ti plate to different area capacities, and then plating at 5 mA/cm²Peeled off to reach a voltage of 0.7V. The electrolyte of all these cells was 1M ZnSO₄(pH about 5).

If the galvanizing capacity is limited to 0.5 mAh/cm²Then more than 2000 cycles may be implemented (2353). When the electroplating is carried out for 10mAh/cm²And then stripped from the titanium electrode surface, only 14 cycles were achieved. There is a trade-off between limiting the cycling capacity to low values to extend the cycling life and the low practical energy density (Wh/kg or Wh/L) of the battery due to the lower active/inactive component ratio. To achieve high energy density while maintaining long cycle life, the optimal area capacity per side of the positive electrode is about 2 mAh/cm²-10 mAh/cm²。

In some cases, the cycle life of a secondary zinc-ion battery (e.g., secondary battery 100 of fig. 1) can be extended by including a gelled electrolyte.

Referring now to fig. 5, shown therein is a graph 500 summarizing the effect of gelled electrolyte in a zinc (Zn | | Zn) symmetric battery, according to one embodiment. Different electrolyte gel formers were tested for electroplating and stripping of zinc metal electrodes (e.g., electrode 10 of fig. 1). Zinc symmetric cells were used as an accelerated test for cell failure.

FIG. 400a shows a battery containing an electrolyteVoltage vs time graph of examples of (a) the electrolyte has 1M ZnSO dissolved in 1 wt% xanthan/hydrogel₄. Arrow 404 represents the point where the cell suffers an internal short circuit due to the connection of zinc metal from the two electrodes that are initially separated by the glass fiber layer.

Figure 400b shows a graph of the number of cycles for different types of gel-forming agents. The number of cycles shown in graph 400b is the number of cycles achieved before an internal short circuit occurs. The gelled electrolyte demonstrated about a 2-fold to about a 4-fold improvement in cycle life for these batteries. Thus, gel-forming agents that increase the viscosity of the electrolyte can be used to improve the cycle life of a zinc ion battery (e.g., battery 100 of fig. 1).

Examples

The secondary battery of the present disclosure (e.g., battery 100 of fig. 1) uses a thin film electrode battery form (e.g., battery forms 200a, 200b, 200c of fig. 2). From a manufacturing point of view, the thin film electrode battery form is attractive because of its relative ease of manufacture. The performance of thin film electrodes may also be preferred compared to thick electrodes.

Referring now to fig. 5, a first cycle voltage profile 500 is shown for a thin film electrode 500a and a thick electrode 500 b. 1M ZnSO dissolved in an aqueous electrolyte₄+ 0.1M MnSO₄In each case at 0.6mA/cm²A circulating thin film electrode and a thick electrode.

The membrane electrode 500a comprised electrolytic manganese dioxide ("EMD") coated on a 15 micron thick rough Ni foil current collector, providing a total electrode thickness of about 100 microns.

The thick electrode 500b contained an EMD with a current collector containing a stainless steel grid (700 microns thick), providing a total electrode thickness of 1.5 mm. Although the thick electrode 500b provides an area capacity about 10 times higher (27 mAh/cm) than that of the thin film electrode²Relative to 2.8 mAh/cm²) However, there is a large overpotential due to kinetic (ion diffusion) limitations in the thick electrode 500 b.

The average discharge voltage of the thin electrode 500a is about 1.3V. The average discharge voltage of the thick electrode 500b is only about 0.8V. The thick electrode 500b cannot be recharged and reaches an upper voltage cutoff of 1.8V almost immediately.

Referring now to fig. 6, a graph 600 showing the cycling performance of the two Zn | | | EMD cells (500a, 500b) of fig. 5 is shown. The cycling performance is determined by the area capacity (mAh/cm) as a function of the number of cycles²) And (4) showing. The thin film electrode 500a was cycled for about 800 cycles. The thick electrode 500b is discharged only once.

Referring now to fig. 7, shown therein is a diagram 700 of an example of a first cycle of a battery (e.g., battery 100 of fig. 1) according to one embodiment. Using a zinc metal negative electrode (Zn foil =30 μ M) (e.g., negative electrode 10 of fig. 1), soaked in 1MZnSO₄Paper separator (160 μ M) (e.g., separator 3 of fig. 1) and Zn on matte Ni foil current collector (15 μ M) (e.g., current collector 5 of fig. 1) in a/water electrolyte_0.25V₂O₅.nH₂A positive electrode (e.g., positive electrode 20 of fig. 1) made of an active coating of O (e.g., active material 4 of fig. 1) produces a battery.

About 3.5 mAh/cm is realized²Area capacity of (c). The density of the zinc metal used (7.14 g/cm)³) And zinc gravimetric capacity (820 mAh/g), per 1mAh/cm²Area capacity, 1.7 μm zinc was circulated. A dense zinc foil was used as the negative electrode, which corresponds to a zinc thickness of 5.95 μm circulating on each side of the electrode (e.g., zinc metal layer 2 of fig. 1) in the cell. If the foil is used as a double-sided electrode (e.g., negative electrode 10 of fig. 1), excess zinc may be used as a current collector (e.g., current collector 1 of fig. 1), and will be equal to about 18.1 μm.

Referring now to fig. 8, shown therein is a diagram 800 of an example of a first cycle of a battery (e.g., battery 100 of fig. 1) according to one embodiment. A zinc metal negative electrode (e.g., negative electrode 10 of fig. 1) comprising zinc (e.g., zinc metal layer 2 of fig. 1) on a 25 μm copper foil current collector (e.g., current collector 1 of fig. 1) and a collector consisting of Na on a rough Ni foil current collector (15 μm) (e.g., current collector 5 of fig. 1) using electroplating_xV₂O₅(SO₄)_y.nH₂A positive electrode (e.g., positive electrode 20 of fig. 1) made of an active coating of O (e.g., active material 4 of fig. 1) produces a battery.

In this example, the area capacity reached 3.9 mAh/cm². Will be provided withAn inert current collector is used for the negative electrode.

The battery includes a separator (e.g., separator 3 of fig. 1). The thickness and composition of the separator has proven to be important to prevent short circuits. The use of puncture resistant materials has been demonstrated to extend cycle life. In this embodiment, the separator is immersed in 1M ZnSO₄Microporous silica coated polyethylene separator in water electrolyte (Entek, 175 μ M).

The following paragraphs describe the experimental methods used herein.

All electrochemical cells were assembled using a homemade plate design that included a rubber gasket sandwiched between two acrylic plates. Acrylic plates were tethered together and covered the electrode stack (negative electrode/separator/positive electrode). The electrode stack is pressed together between the Ti plates by an external screw (2 in-lb torque) which also serves as an electrical connection.

A Zn | Ti cell (e.g., fig. 3) was prepared using a piece of zinc foil (250 μm thick) as the negative electrode and a titanium plate as the positive electrode, 5.5 cm × 5.5.5 cm for the zinc piece and 4 cm × 4 cm for the titanium, a monolithic glass fiber filter membrane (about 300 μm thick) for the separator, and an applied current density of 5 mA/cm²(based on titanium electrode = 16 cm)²) And 5mAh/cm²Zinc (g) is plated onto titanium. The zinc was then stripped from the titanium to a voltage cut-off of 0.7V. The electrolyte is 1M ZnSO dissolved in water₄(pH about 5) which was added to the septum in a volume of about 3 mL.

A Zn | Zn symmetric cell (e.g., fig. 4) was prepared using two sheets of zinc foil (30 μm thick) as both the negative and positive electrodes, one sheet of zinc was 5.5 cm × 5.5.5 cm and the other sheet of zinc was 5 cm × 5 cm, the separator was a monolithic glass fiber filter membrane (about 300 μm thick), the applied current density was 5 mA/cm²(based on smaller electrodes = 25 cm)²) And a circulation capacity of 5mAh/cm². The electrolyte tested was added to the separator in a volume of about 3 mL. The electrolytes tested were based on 1MZnSO dissolved in water₄With or without the following gel-forming agents: 1 wt.% agar, 1 wt.% xanthan gum, 10 wt.% fumed silica particles and 4 wt.% carboxymethylcellulose (CMC).

Zinc ion batteries (such as the zinc ion batteries shown in fig. 5-8) are assembled using a 5.5 cm x 5.5 cm zinc negative electrode, a separator with about 3 mL electrolyte, and a positive electrode (5 cm x 5 cm) consisting of an active material coating on a current collector.

The positive electrode of cell 500a shown in fig. 5 was prepared by casting a slurry of electrolytic manganese dioxide (EMD, Tronox), Vulcan XC72 carbon black (Cabot Corp.), and polyvinylidene fluoride (PVDF) binder (HSV1800, Arkema) in a weight ratio of 93.5:4:2.5 in N-methyl-2-pyrrolidone (NMP, Sigma Aldrich) solvent onto a sheet of a roughened Ni foil current collector (Tarray, 15 μm thick). After casting, the electrode was dried in an air stream at 80 ℃ for 20 minutes and then dried in a partial vacuum at 120 ℃ for 2 hours. The electrolyte used in the cell was 1M ZnSO in water₄+ 0.1MMnSO₄. The separator used was a paper filter (160 μm thick). The zinc negative electrode was zinc foil (30 μm thick, Linyi gel libco., Ltd.). The battery is 0.6mA/cm between 0.8V and 1.8V²And (6) circulating.

The positive electrode of cell 500b shown in fig. 5 was prepared by spreading a mass of electrolytic manganese dioxide (EMD, Trono), Vulcan XC72 carbon black (Cabot Corp.), and agar gel with a small amount of water in a weight ratio of 88:10:2 on a stainless steel grid (20 mesh, 700 μm thick, McMaster Carr). After casting, the electrode was calendered to a thickness of 1.5 mm. The electrolyte used in the cell was 1M ZnSO in water₄+ 0.1M MnSO₄. The separator used was a glass fiber filter membrane (about 300 μm thick). The zinc negative electrode was zinc foil (80 μm thick, Linyi Gelon LIB co., Ltd.). The battery is between 0.5V and 1.8V at a voltage of 2.0mA/cm²And (6) circulating.

By reacting the synthesized Zn_0.25V₂O₅.nH₂O, Super C45 carbon black (Timcal) and polyvinylidene fluoride (PVDF) binder (HSV900, Arkema) were cast as a slurry in a weight ratio of 93.5:4:2.5 in N-methyl-2-pyrrolidone (NMP) solvent onto a sheet of roughened Ni foil (15 μm thick, Tarray) to prepare the positive electrode of the cell shown in fig. 7. After casting, the electrode was dried at 80 ℃ under partial vacuum for 2 hours and then calendered. The electrolyte used in the cell was 1M ZnSO in water₄. The separator used was a paper filter (160 μm thick). The zinc negative electrode was zinc foil (30 μm thick, Linyi Gelon LIB co., Ltd.). In brief, by mixing V₂O₅Dissolved in a solution containing 30 wt.% of H₂O₂0.1M ZnCl₂In solution, synthesis of Zn_0.25V₂O₅.nH₂And O. The mixture was aged for 1 day, and then the solid product was filtered and washed with deionized water. Finally, the product was dried in a vacuum oven at 80 ℃ overnight, with the cell at 0.2 mA/cm between 0.5V and 1.4V²And (6) circulating.

By mixing the synthesized Na_xV₂O₅(SO₄)_y.nH₂O, Vulcan XC72 carbon black (Cabot corporation) and polyvinylidene fluoride (PVDF) binder (HSV1800, Arkema) were cast into a slurry of 93.5:4:2.5 weight ratio onto a sheet of a roughened Ni foil current collector (Tarray, 15 μm thick) in N-methyl-2-pyrrolidone (NMP, Sigma Aldrich) solvent to prepare the positive electrode of the cell shown in fig. 8. After casting, the electrode was dried in an air stream at 80 ℃ for 20 minutes and then dried in a partial vacuum at 120 ℃ for 2 hours. The electrolyte used in the cell was 1M ZnSO in water₄. The separator used was a microporous silica coated polyethylene separator (Entek, 175 microns thick). The zinc negative electrode was a piece of zinc (30 μm thick) plated on a copper foil current collector (25 μm thick, McMaster Carr). Briefly, by using H₂SO₄Acidifying NaVO₃The solution was dissolved and the mixture was allowed to react for 20 minutes under boiling to synthesize Na_xV₂O₅(SO₄)_y.nH₂And O. The precipitate was then filtered and dried in air at 60 ℃ overnight. The battery is 0.6mA/cm between 0.5V and 1.4V²And (6) circulating.

While the above description provides examples of one or more apparatuses, methods, or systems, it should be understood that other apparatuses, methods, or systems may be within the scope of the claims as interpreted by one of ordinary skill in the art.