CN115954439A - Reference electrode and method for producing same - Google Patents
Reference electrode and method for producing same Download PDFInfo
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- CN115954439A CN115954439A CN202310099176.6A CN202310099176A CN115954439A CN 115954439 A CN115954439 A CN 115954439A CN 202310099176 A CN202310099176 A CN 202310099176A CN 115954439 A CN115954439 A CN 115954439A
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- 238000004519 manufacturing process Methods 0.000 title claims description 7
- 229910052744 lithium Inorganic materials 0.000 claims abstract description 132
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 claims abstract description 126
- 239000007772 electrode material Substances 0.000 claims abstract description 40
- 239000000463 material Substances 0.000 claims abstract description 23
- 230000020477 pH reduction Effects 0.000 claims abstract description 11
- 229910052751 metal Inorganic materials 0.000 claims description 54
- 239000002184 metal Substances 0.000 claims description 54
- 238000005538 encapsulation Methods 0.000 claims description 49
- 238000000034 method Methods 0.000 claims description 48
- 238000004806 packaging method and process Methods 0.000 claims description 33
- 239000007769 metal material Substances 0.000 claims description 16
- 229920000620 organic polymer Polymers 0.000 claims description 16
- KRHYYFGTRYWZRS-UHFFFAOYSA-N Fluorane Chemical compound F KRHYYFGTRYWZRS-UHFFFAOYSA-N 0.000 claims description 14
- 239000010949 copper Substances 0.000 claims description 14
- 239000002861 polymer material Substances 0.000 claims description 14
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 claims description 13
- 229910052802 copper Inorganic materials 0.000 claims description 13
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 claims description 10
- 238000002844 melting Methods 0.000 claims description 9
- 230000008018 melting Effects 0.000 claims description 9
- 239000011259 mixed solution Substances 0.000 claims description 9
- 238000000576 coating method Methods 0.000 claims description 8
- -1 polyethylene Polymers 0.000 claims description 8
- 238000000151 deposition Methods 0.000 claims description 7
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims description 6
- 239000011261 inert gas Substances 0.000 claims description 6
- 238000005096 rolling process Methods 0.000 claims description 6
- 150000002500 ions Chemical class 0.000 claims description 5
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 claims description 4
- 229920003171 Poly (ethylene oxide) Polymers 0.000 claims description 4
- 239000004698 Polyethylene Substances 0.000 claims description 4
- 239000004743 Polypropylene Substances 0.000 claims description 4
- 229910017604 nitric acid Inorganic materials 0.000 claims description 4
- 229920005569 poly(vinylidene fluoride-co-hexafluoropropylene) Polymers 0.000 claims description 4
- 229920000573 polyethylene Polymers 0.000 claims description 4
- 229920001155 polypropylene Polymers 0.000 claims description 4
- 238000004544 sputter deposition Methods 0.000 claims description 4
- 238000001771 vacuum deposition Methods 0.000 claims description 4
- 229910000838 Al alloy Inorganic materials 0.000 claims description 3
- 229910000881 Cu alloy Inorganic materials 0.000 claims description 3
- 229910000640 Fe alloy Inorganic materials 0.000 claims description 3
- 229910000990 Ni alloy Inorganic materials 0.000 claims description 3
- 229910052742 iron Inorganic materials 0.000 claims description 3
- 238000002360 preparation method Methods 0.000 abstract description 24
- 239000003792 electrolyte Substances 0.000 abstract description 19
- 238000005260 corrosion Methods 0.000 abstract description 6
- 230000007797 corrosion Effects 0.000 abstract description 6
- 239000010410 layer Substances 0.000 description 123
- HBBGRARXTFLTSG-UHFFFAOYSA-N Lithium ion Chemical compound [Li+] HBBGRARXTFLTSG-UHFFFAOYSA-N 0.000 description 16
- 229910001416 lithium ion Inorganic materials 0.000 description 16
- 239000002253 acid Substances 0.000 description 8
- 239000000126 substance Substances 0.000 description 8
- 230000000694 effects Effects 0.000 description 7
- MUBZPKHOEPUJKR-UHFFFAOYSA-N Oxalic acid Chemical compound OC(=O)C(O)=O MUBZPKHOEPUJKR-UHFFFAOYSA-N 0.000 description 6
- 239000013543 active substance Substances 0.000 description 6
- 238000011065 in-situ storage Methods 0.000 description 6
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical compound O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 6
- NWFNSTOSIVLCJA-UHFFFAOYSA-L copper;diacetate;hydrate Chemical compound O.[Cu+2].CC([O-])=O.CC([O-])=O NWFNSTOSIVLCJA-UHFFFAOYSA-L 0.000 description 5
- 238000009713 electroplating Methods 0.000 description 5
- 229910000733 Li alloy Inorganic materials 0.000 description 4
- 238000006243 chemical reaction Methods 0.000 description 4
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- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 description 4
- 238000001556 precipitation Methods 0.000 description 4
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- 239000011248 coating agent Substances 0.000 description 3
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- 239000002245 particle Substances 0.000 description 3
- 238000003860 storage Methods 0.000 description 3
- 230000003746 surface roughness Effects 0.000 description 3
- 238000004804 winding Methods 0.000 description 3
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 2
- 238000010306 acid treatment Methods 0.000 description 2
- 230000032683 aging Effects 0.000 description 2
- 229910045601 alloy Inorganic materials 0.000 description 2
- 239000000956 alloy Substances 0.000 description 2
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 2
- 230000000295 complement effect Effects 0.000 description 2
- 150000001875 compounds Chemical class 0.000 description 2
- 150000001879 copper Chemical class 0.000 description 2
- PCHJSUWPFVWCPO-UHFFFAOYSA-N gold Chemical compound [Au] PCHJSUWPFVWCPO-UHFFFAOYSA-N 0.000 description 2
- 229910052737 gold Inorganic materials 0.000 description 2
- 239000010931 gold Substances 0.000 description 2
- 230000002045 lasting effect Effects 0.000 description 2
- 150000002641 lithium Chemical class 0.000 description 2
- 239000012046 mixed solvent Substances 0.000 description 2
- 235000006408 oxalic acid Nutrition 0.000 description 2
- 239000001301 oxygen Substances 0.000 description 2
- 229910052760 oxygen Inorganic materials 0.000 description 2
- 229910052697 platinum Inorganic materials 0.000 description 2
- 238000004451 qualitative analysis Methods 0.000 description 2
- 238000004445 quantitative analysis Methods 0.000 description 2
- 239000000853 adhesive Substances 0.000 description 1
- 230000001070 adhesive effect Effects 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- UBAZGMLMVVQSCD-UHFFFAOYSA-N carbon dioxide;molecular oxygen Chemical compound O=O.O=C=O UBAZGMLMVVQSCD-UHFFFAOYSA-N 0.000 description 1
- 238000005253 cladding Methods 0.000 description 1
- 239000011247 coating layer Substances 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 229940116318 copper carbonate Drugs 0.000 description 1
- GEZOTWYUIKXWOA-UHFFFAOYSA-L copper;carbonate Chemical compound [Cu+2].[O-]C([O-])=O GEZOTWYUIKXWOA-UHFFFAOYSA-L 0.000 description 1
- 230000005684 electric field Effects 0.000 description 1
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Classifications
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/10—Energy storage using batteries
Abstract
The invention provides a preparation method of a reference electrode and the reference electrode. The preparation method of the reference electrode comprises the following steps: providing a current collector, and carrying out acidification treatment on the surface of the current collector; providing a lithium electrode material, and arranging the lithium electrode material on the surface of a current collector to form a lithium electrode layer; and providing an encapsulating material, and arranging the encapsulating material on the surface of the lithium electrode layer to form an encapsulating layer. The reference electrode prepared by the preparation method has good electrolyte corrosion resistance, can ensure the potential stability of the reference electrode, and has simple and easy preparation process and strong operability.
Description
Technical Field
The invention relates to the technical field of batteries, in particular to a preparation method of a reference electrode and the reference electrode.
Background
In recent years, lithium ion batteries have been widely used in electric vehicles because of their advantages such as high energy density and long cycle life. However, during the use of the battery, the negative pole lithium precipitation reaction is one of the most important factors causing the aging of the battery and often brings about safety risks. Research shows that the reference electrode is implanted in the battery, so that the potentials of the positive electrode and the negative electrode can be tested in situ, and qualitative and quantitative analysis can be performed on the lithium precipitation reaction of the negative electrode of the lithium ion battery. An excellent reference electrode is often required to have the following basic characteristics: reversibility is good, and the electrode potential conforms to Nernst equation; the reference electrode has good chemical stability and electrochemical stability in the cell, and the electrode potential is kept constant.
Metallic lithium, metallic lithium alloy, lithium-containing compound with electrochemical activity, etc. are usually used as reference electrodes, and the common preparation methods include a direct implantation method and an in-situ deposition method. The direct implantation method is to directly put metallic lithium in a battery in the form of a lithium strip as a reference electrode, and the in-situ deposition method is to reduce lithium ions on a target electrode into lithium metal or a lithium metal alloy through electroplating to become the reference electrode. The preparation method does not consider the high activity of the metal lithium, namely the metal lithium is easy to react with the electrolyte and dissolve, so that the service life of the reference electrode is not long enough, and the potential monitoring of the anode and the cathode in the long-term circulation process of the lithium battery cannot be met.
Disclosure of Invention
The embodiment of the invention provides a preparation method of a reference electrode and the reference electrode, the reference electrode prepared by the preparation method has good electrolyte corrosion resistance, the potential stability of the reference electrode can be ensured, and the whole preparation process of the reference electrode is simple and easy to implement and has strong operability.
In a first aspect, an embodiment of the present invention provides a method for preparing a reference electrode, including:
providing a current collector, and performing acidification treatment on the surface of the current collector;
providing a lithium electrode material, and arranging the lithium electrode material on the surface of the current collector to form a lithium electrode layer;
providing an encapsulating material, and arranging the encapsulating material on the surface of the lithium electrode layer to form an encapsulating layer.
In an embodiment, the material of the current collector is one or more of copper, copper alloy, aluminum alloy, nickel alloy, iron, and iron alloy.
In an embodiment, the acidizing the surface of the current collector includes: providing a mixed solution of sulfuric acid, nitric acid and hydrofluoric acid; immersing the current collector in the mixed solution.
In one embodiment, the current collector is in a mesh shape, and the mesh number of the current collector ranges from 8 meshes to 1000 meshes.
In one embodiment, the disposing the lithium electrode material on the surface of the current collector to form a lithium electrode layer includes: and arranging the lithium electrode material on the surface of the current collector by adopting a melting method or a rolling method in an inert gas atmosphere.
In one embodiment, the providing an encapsulation material, disposing the encapsulation material on a surface of the lithium electrode layer to form an encapsulation layer, includes: providing an inert metal material, and arranging the inert metal material on the surface of the lithium electrode layer to form a metal packaging layer.
In one embodiment, the disposing the inert metal material on the surface of the lithium electrode layer to form a metal encapsulation layer includes: and depositing the inert metal material on the surface of the lithium electrode layer by adopting a vacuum coating method or an ion sputtering coating method.
In one embodiment, the thickness of the metal encapsulation layer is 5nm to 10nm.
In an embodiment, after the disposing the inert metal material on the surface of the lithium electrode layer to form a metal encapsulation layer, the method further includes: providing an organic polymer material, and arranging the organic polymer material on the surface of the metal packaging layer to form an organic packaging layer; the organic polymer material comprises one or more of polyethylene, polypropylene, polyvinylidene fluoride-hexafluoropropylene copolymer, and polyethylene oxide.
In a second aspect, embodiments of the present invention provide a reference electrode, comprising:
a current collector, the surface of which is acidified;
the lithium electrode layer is arranged on the surface of the current collector;
and the packaging layer is arranged on the surface of the lithium electrode layer.
In an embodiment of the present invention, a method for manufacturing a reference electrode is provided, where the method includes providing a current collector, a lithium electrode material, and an encapsulation material, performing an acidification treatment on a surface of the current collector, disposing the lithium electrode material on the surface of the current collector to form a lithium electrode layer, and disposing the encapsulation material on a side of the lithium electrode layer away from the current collector to coat the lithium electrode layer. As can be understood, on one hand, the surface roughness of the current collector is increased by performing acidification treatment on the surface of the current collector, so that the firmness of the lithium electrode material attached to the current collector is improved; on the other hand, the lithium electrode layer is coated by the packaging material, so that a packaging layer is formed on the surface of the lithium electrode layer, the lithium electrode layer is prevented from contacting electrolyte, and the stability of the reference electrode is improved. Therefore, the reference electrode prepared by the preparation method has good electrolyte corrosion resistance, the potential stability of the reference electrode can be ensured, and the whole preparation process of the reference electrode is simple and easy to implement and has strong operability.
Drawings
In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the description of the embodiments will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.
Fig. 1 is a schematic flow chart of a method for manufacturing a reference electrode according to an embodiment of the present invention.
Fig. 2 is a graph illustrating the effect of potential variation of the negative electrode-reference electrode of the lithium ion battery using the reference electrode provided by the embodiment of the present invention.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be obtained by a person skilled in the art without inventive step based on the embodiments of the present invention, are within the scope of protection of the present invention. Furthermore, it should be understood that the detailed description and specific examples, while indicating the present invention, are given by way of illustration and explanation only, and are not intended to limit the present invention. In the present invention, unless otherwise specified, the use of directional terms such as "upper" and "lower" generally means upper and lower in the actual use or operation of the device, particularly in the orientation of the figures of the drawings; while "inner" and "outer" are with respect to the outline of the device.
In recent years, lithium ion batteries have been widely used in electric vehicles due to their advantages such as high energy density and long cycle life. However, during the use of the battery, the negative pole lithium precipitation reaction is one of the most important factors causing the aging of the battery and often brings about safety risks. Research shows that the reference electrode is implanted in the battery, so that the potentials of the positive electrode and the negative electrode can be tested in situ, and qualitative and quantitative analysis can be performed on the lithium precipitation reaction of the negative electrode of the lithium ion battery. An excellent reference electrode is often required to have the following basic characteristics: reversibility is good, and the electrode potential conforms to Nernst equation; the reference electrode has good chemical stability and electrochemical stability in the cell, and the electrode potential is kept constant.
Metallic lithium, metallic lithium alloy, lithium-containing compound with electrochemical activity, etc. are usually used as reference electrodes, and the common preparation methods include a direct implantation method and an in-situ deposition method. The direct implantation method is to directly put metallic lithium in a battery in the form of a lithium strip as a reference electrode, and the in-situ deposition method is to reduce lithium ions on a target electrode into lithium metal or a lithium metal alloy through electroplating to become the reference electrode. The preparation method does not consider the high activity of the metal lithium, namely the metal lithium is easy to react with the electrolyte and dissolve, so that the service life of the reference electrode is not long enough, and the potential monitoring of the anode and the cathode in the long-term circulation process of the lithium battery cannot be met.
In contrast, the embodiment of the invention provides a preparation method of a reference electrode and the reference electrode, the reference electrode prepared by the preparation method has good electrolyte corrosion resistance, the potential stability of the reference electrode can be ensured, and the whole preparation process of the reference electrode is simple and easy to implement and has strong operability. The following detailed description is made with reference to the accompanying drawings.
Referring to fig. 1, fig. 1 is a schematic flow chart of a method for manufacturing a reference electrode according to an embodiment of the present invention.
Embodiments of the present application provide a method for manufacturing a reference electrode, which includes the following steps.
S100, providing a current collector, and carrying out acidizing treatment on the surface of the current collector.
The current collector refers to a structure or a part for collecting current, and mainly collects current generated by active substances of a lithium battery so as to form large current to be output to the outside, so that the current collector is in full contact with the active substances, and the resistance value is small.
It can be understood that the current collector is generally made of metal, and has small internal resistance; if the metal is oxidized, the resistance value is likely to increase. So the surface of the current collector is acidified, and on one hand, the metal oxide on the metal surface is removed; on the other hand, the roughness of the current collector can be increased through chemical corrosive acid treatment, the attachment area of the active substances of the reference electrode is increased, and the attachment reliability of the active substances is improved.
The current collector may be made of one or more of copper, copper alloy, aluminum alloy, nickel alloy, iron, and iron alloy.
For example, when the material of the current collector is copper, the copper reacts with oxygen, carbon dioxide, water vapor and other substances in the air to generate basic copper carbonate (Cu (OH) CO), which is also called verdigris. The copper verdigris can be reacted with a chemically aggressive acid to yield a water soluble copper salt. For example, the chemically aggressive acid is hydrochloric acid, sulfuric acid, oxalic acid or hydrofluoric acid or a mixed acid thereof.
The amount or type of the chemically corrosive acid may depend on the material of the current collector and the desired surface area of the current collector for use in the electrochemical process. After the chemically corrosive acid has sufficiently etched the metal oxide on the surface of the current collector, the deionized water can be used to rinse away the copper salts and excess chemically corrosive acid on the surface of the electrode. It should be noted that, in order to avoid the reformation of metal oxide on the surface of the reference electrode, the acidification treatment and the rinsing may be performed in an oxygen-free environment, or before the rinsing, an inert gas may be introduced into the deionized water to reduce oxygen in the deionized water.
Optionally, the chemically aggressive acid may be one or more of sulfuric acid, nitric acid, oxalic acid, and hydrofluoric acid.
The shape of the current collector may be any of a linear shape, a foil shape, and a mesh shape. Optionally, when the current collector is in a net shape, the contact area between the current collector and the lithium electrode material is large, the adhesion degree of the lithium electrode material is tighter, and the reliability of the reference electrode is improved. When the current collector is in a mesh shape, the mesh number of the current collector may range from 8 mesh to 1000 mesh, such as 8 mesh to 20 mesh, 15 mesh to 30 mesh, 25 mesh to 50 mesh, 30 mesh to 100 mesh, 80 mesh to 200 mesh, 100 mesh to 300 mesh, 250 mesh to 500 mesh, 400 mesh to 600 mesh, 500 mesh to 800 mesh, 600 mesh to 900 mesh, or 800 mesh to 1000 mesh; for example, 8 mesh, 20 mesh, 50 mesh, 100 mesh, 200 mesh, 400 mesh, 700 mesh or 1000 mesh. It is understood that, as the mesh number of the metal mesh is smaller, the number of pores per square centimeter is smaller, and the more material per unit volume of the current collector is, which is advantageous to increase the stability of the current collector. When the mesh number of the metal mesh is larger, the number of the holes per square centimeter is larger, the material of the unit volume of the current collector is smaller, and the weight and the cost of the current collector are favorably reduced.
S200, providing a lithium electrode material, and arranging the lithium electrode material on the surface of a current collector to form a lithium electrode layer.
The lithium electrode material may be disposed on the surface of the current collector by an electroplating method, a melting method, a rolling method, or a winding method. When the lithium electrode material is arranged on the surface of the current collector by an electroplating method, the current collector is a cathode, lithium ions in the electrolyte flow to the cathode under the action of an electric field force, and are reduced and deposited to be a metal lithium layer at the plated part of the current collector to form a lithium electrode layer. When the lithium electrode material is arranged on the surface of the current collector through a melting method, the lithium electrode material is heated to a melting state, then the lithium electrode material is coated on the current collector, and a lithium electrode layer is formed on the surface of the current collector after cooling. When the lithium electrode material is arranged on the surface of the current collector through a rolling method, high voltage is applied to the solid lithium electrode material below a melting point, and the particles are effectively fused with the particles through the deformation of the current collector and the particles of the lithium electrode material, so that the lithium electrode material is fixed on the current collector. When the lithium electrode material is disposed on the surface of the current collector by a winding method, the band-shaped lithium electrode material is wound on the current collector.
For example, the electroplating method is to electroplate a lithium electrode material on a linear current collector. The melting method is to melt the lithium electrode material and a foil-like current collector. The roll method refers to a winding method in which a lithium electrode material is rolled on a mesh-shaped current collector, and the lithium electrode material is wound on a linear current collector, and the thickness of the lithium electrode material may be 25 μm.
Alternatively, the lithium electrode material may be metallic lithium or a lithium alloy. Since metallic lithium or lithium alloy is an active metal, it may be oxidized by oxygen in the air. The lithium electrode layer is formed by disposing a lithium electrode material on the surface of a current collector in an inert gas atmosphere.
S300, providing a packaging material, and arranging the packaging material on the surface of the lithium electrode layer to form a packaging layer.
The encapsulating material may be an inert metal material or an organic polymer material. The inert metal material may be an inert metal such as gold or platinum. The organic polymer material may be a polymer such as polyethylene, polypropylene, polyvinylidene fluoride-hexafluoropropylene copolymer, or polyethylene oxide.
In one case, the inert metal material is disposed on the surface of the lithium electrode layer to form a metal encapsulation layer, the organic polymer material is disposed on the surface of the metal encapsulation layer to form an organic encapsulation layer, and finally the encapsulation layer is formed on the surface of the lithium electrode layer. It is understood that, on the one hand, by forming a metal encapsulation layer on the surface of the lithium electrode layer, the metal encapsulation layer is excellent in chemical stability, does not react with hydrofluoric acid in the electrolyte, and can permanently protect the potential stability of the lithium electrode layer; on the other hand, by forming an organic encapsulation layer on the surface of the lithium electrode layer, the organic encapsulation layer has hydrophobicity and ion conduction properties, and can also permanently protect the potential stability of the lithium electrode layer; in addition, the surface of the metal packaging layer may be rough, and the organic packaging layer structure is arranged on the surface of the metal packaging layer to form a smooth surface, that is, a uniform metal-inorganic packaging layer is formed on the surface of the reference electrode, so that the stability of the reference electrode in the electrolyte is greatly improved. The metal packaging layer and the organic packaging layer form a packaging layer with complementary cladding.
In another case, the organic polymer material is first disposed on the surface of the lithium electrode layer to form an organic encapsulation layer, and the inert metal material is then disposed on the surface of the organic encapsulation layer to form a metal encapsulation layer.
In some embodiments, the step of subjecting the surface of the current collector to an acidification treatment includes providing a mixed solution of sulfuric acid, nitric acid, and hydrofluoric acid, and immersing the current collector in the mixed solution. It is understood that the surface of the current collector is acidified by the mixed solution. On one hand, removing the metal oxide on the surface of the metal; on the other hand, the chemical corrosive acid treatment can increase the roughness of the current collector, is beneficial to increasing the attachment area of the active substance of the reference electrode and improves the reliability of the attachment of the active substance. For example, the current collector is made of copper and has a mesh shape, and the mass concentration of the mixed solvent is 10mol/L. The reticulated copper current collector was immersed in the mixed solution for 10 minutes. If the current collector has verdigris, the mixed solvent reacts with the verdigris to remove the verdigris; and reacting the copper current collector to improve the roughness of the copper current collector.
In some embodiments, the step of disposing the lithium electrode material on the surface of the current collector to form the lithium electrode layer includes disposing the lithium electrode material on the surface of the current collector by a melting method or a rolling method in an inert gas atmosphere.
The method comprises the step of depositing the inert metal material on the surface of the lithium electrode layer by adopting a vacuum coating method or an ion sputtering coating method. The thickness of the metal encapsulation layer may be 5nm to 10nm, for example 4.5nm, 5nm, 6nm, 7nm, 8nm, 9nm, 10nm or 10.5nm. It is understood that the thickness of the metal encapsulation layer may vary from place to place due to differences in processing accuracy and surface flatness of the lithium electrode layer.
In some embodiments, after the step of disposing the inert metal material on the surface of the lithium electrode layer to form the metal encapsulation layer, the method for preparing the reference electrode further comprises providing an organic polymer material, and disposing the organic polymer material on the surface of the metal encapsulation layer to form the organic encapsulation layer. The organic polymer material comprises one or more of polyethylene, polypropylene, polyvinylidene fluoride-hexafluoropropylene copolymer, and polyethylene oxide. It can be understood that the surface of the metal encapsulation layer may be rough, and then the organic encapsulation layer structure is disposed on the surface of the metal encapsulation layer to form a smooth surface, that is, a uniform metal-inorganic encapsulation layer is formed on the surface of the reference electrode, which greatly improves the stability of the reference electrode in the electrolyte.
Optionally, the organic polymer material may be uniformly coated on the surface of the metal encapsulation layer through solution foaming, so as to further form an encapsulation layer coated complementarily with the metal encapsulation layer and the organic encapsulation layer. The organic encapsulation layer may have a thickness of 5mm to 10mm, for example 4.5mm, 5mm, 6mm, 7mm, 8mm, 9mm, 10mm or 10.5mm. It is understood that the thickness of the organic encapsulation layer may be different from place to place due to differences in processing accuracy of the organic encapsulation layer or surface flatness of the lithium electrode layer.
In some scenarios, the reference electrode in the present application is prepared by: 1:1:1, carrying out acidification treatment on a current collector of a copper mesh (the aperture range of the copper mesh is 8 meshes to 10000 meshes) by using the mixed solution in the proportion, then carrying out water washing and vacuum drying to obtain a roughened current collector, wherein the treatment method can improve the surface roughness of the current collector and improve the adhesive force of the surface of the current collector; uniformly attaching metal lithium to a copper mesh in a melting coating or cold pressing mode under the atmosphere of inert gas to form a lithium electrode layer; the metal packaging layer of gold or platinum with the thickness of 5-10 nm is plated on the surface of the lithium electrode layer through a vacuum coating method or an ion sputtering coating method, the metal packaging layer is excellent in chemical stability, does not react with hydrofluoric acid in electrolyte, and can permanently protect the potential stability of metal lithium. And uniformly coating the organic polymer on the metal packaging layer by soaking in the solution to further form the reference electrode coated with the metal coating and the organic protective layer in a complementary manner.
The reference electrode is assembled into a lithium ion battery, and the potential change of the negative electrode and the reference electrode is monitored. Referring to fig. 2, fig. 2 is a graph illustrating the effect of potential variation of the negative electrode-reference electrode of the lithium ion battery using the reference electrode according to the embodiment of the present invention. The three-electrode lithium ion battery prepared by adopting the reference electrode has the voltage drop of only 0.03V within 6 months of the potential of the negative electrode-reference electrode under the protection of the metal-organic polymer coating layer. Compared with the traditional reference electrode for the lithium ion battery, the reference electrode has lasting effective time, and can meet the long-term circulation and storage potential monitoring of the commercial power battery.
The embodiment of the application also provides a reference electrode, and this reference electrode includes mass flow body, lithium electrode layer and encapsulated layer. The surface of the current collector is treated with an acid to improve roughness. The lithium electrode layer is arranged on the surface of the current collector. The packaging layer is arranged on the surface of the lithium electrode layer.
Optionally, the lithium electrode layer is coated on the surface of the current collector. The packaging layer is coated on the surface of the lithium electrode layer. It is understood that the current collector serves to support the lithium electrode layer, and the encapsulation layer serves to protect the lithium electrode layer.
Optionally, the encapsulation layer includes a metal encapsulation layer and an organic encapsulation layer. The metal packaging layer is arranged on the surface of the lithium electrode layer, and the organic packaging layer is arranged on the surface of the metal packaging layer. It is understood that the metal encapsulation layer can block the corrosion of the lithium electrode layer by the electrolyte after being arranged on the surface of the lithium electrode layer. However, the surface of the metal encapsulation layer may be rough, and the organic encapsulation layer is disposed on the surface of the metal encapsulation layer, that is, a uniform metal-inorganic encapsulation layer is formed on the surface of the reference electrode. It will be appreciated that the rougher the surface of the material, the greater the contact area with the surrounding medium, and thus the greater the probability and degree of physicochemical changes to the material. The organic packaging layer is arranged on the surface of the metal packaging layer, so that the direct contact between the rough metal packaging layer and the electrolyte can be prevented from generating physical and chemical changes, and the stability of the reference electrode in the electrolyte is greatly improved.
The embodiment of the application also provides a lithium ion battery, which comprises the reference electrode.
In an embodiment of the invention, a preparation method of a reference electrode and the reference electrode are provided, the preparation method of the reference electrode includes providing a current collector, a lithium electrode material and an encapsulation material, performing an acidification treatment on the surface of the current collector, disposing the lithium electrode material on the surface of the current collector to form a lithium electrode layer, and disposing the encapsulation material on a side of the lithium electrode layer away from the current collector to coat the lithium electrode layer. As can be understood, on one hand, the surface roughness of the current collector is increased by performing acidification treatment on the surface of the current collector, so that the firmness of the lithium electrode material attached to the current collector is improved; on the other hand, the lithium electrode layer is coated by the packaging material, so that a packaging layer is formed on the surface of the lithium electrode layer, the lithium electrode layer is prevented from contacting electrolyte, and the stability of the reference electrode is improved. Therefore, the reference electrode prepared by the preparation method has good electrolyte corrosion resistance, the potential stability of the reference electrode can be ensured, and the whole preparation process of the reference electrode is simple and easy to implement and has strong operability.
In addition, the reference electrode and the preparation method thereof provided by the application also have the following technical effects:
firstly, the reference electrode can obviously inhibit the thermodynamic instability of a lithium electrode and the external environment in the practical application process, reduce the contact between wet air and electrolyte and the reference electrode, ensure the exchange of lithium ions at the electrode, and obviously improve the air stability of the reference electrode, thereby further improving the storage and transportation performance and the service life of the reference electrode.
And secondly, a coating method of complementing the metal packaging layer and the organic packaging layer is adopted, so that a uniform metal-inorganic packaging layer is formed on the surface of the reference electrode, and the stability of the reference electrode in electrolyte is greatly improved.
And thirdly, under the protection of the metal-organic packaging layer, the voltage drop of the negative electrode-reference electrode in 6 months of the lithium ion battery prepared by the preparation method of the reference electrode is only 0.03V. Compared with the traditional reference electrode for the lithium ion battery, the reference electrode has lasting effective time, and can meet the long-term circulation and storage potential monitoring of the commercial power battery.
The above embodiments of the present invention are described in detail, and the principle and the implementation of the present invention are explained by applying specific embodiments, and the above description of the embodiments is only used to help understanding the method of the present invention and the core idea thereof; meanwhile, for those skilled in the art, according to the idea of the present invention, the specific embodiments and the application range may be changed, and in summary, the content of the present specification should not be construed as limiting the present invention.
Claims (10)
1. A method of making a reference electrode, comprising:
providing a current collector, and carrying out acidification treatment on the surface of the current collector;
providing a lithium electrode material, and arranging the lithium electrode material on the surface of the current collector to form a lithium electrode layer;
providing an encapsulating material, and arranging the encapsulating material on the surface of the lithium electrode layer to form an encapsulating layer.
2. The method for preparing the reference electrode according to claim 1, wherein the material of the current collector is one or more of copper, copper alloy, aluminum alloy, nickel alloy, iron and iron alloy.
3. The method for preparing a reference electrode according to claim 1, wherein the step of subjecting the surface of the current collector to an acidification treatment comprises: providing a mixed solution of sulfuric acid, nitric acid and hydrofluoric acid; immersing the current collector in the mixed solution.
4. The method for preparing the reference electrode according to claim 1, wherein the current collector is in a mesh shape, and the mesh number of the current collector ranges from 8 meshes to 1000 meshes.
5. The method for preparing the reference electrode according to claim 1, wherein the disposing the lithium electrode material on the surface of the current collector to form a lithium electrode layer comprises: and under the inert gas atmosphere, adopting a melting method or a rolling method to arrange the lithium electrode material on the surface of the current collector.
6. The method for preparing the reference electrode according to any one of claims 1 to 5, wherein the providing of the encapsulating material and the disposing of the encapsulating material on the surface of the lithium electrode layer to form an encapsulating layer comprise: providing an inert metal material, and arranging the inert metal material on the surface of the lithium electrode layer to form a metal packaging layer.
7. The method for preparing the reference electrode according to claim 6, wherein the disposing the inert metal material on the surface of the lithium electrode layer to form a metal encapsulation layer comprises: and depositing the inert metal material on the surface of the lithium electrode layer by adopting a vacuum coating method or an ion sputtering coating method.
8. The method of manufacturing a reference electrode according to claim 6, wherein the metal encapsulation layer has a thickness of 5nm to 10nm.
9. The method for preparing the reference electrode according to claim 6, wherein after disposing the inert metal material on the surface of the lithium electrode layer to form a metal encapsulation layer, the method further comprises: providing an organic polymer material, and arranging the organic polymer material on the surface of the metal packaging layer to form an organic packaging layer; the organic polymer material comprises one or more of polyethylene, polypropylene, polyvinylidene fluoride-hexafluoropropylene copolymer, and polyethylene oxide.
10. A reference electrode, comprising:
a current collector, the surface of which is acidified;
the lithium electrode layer is arranged on the surface of the current collector;
and the packaging layer is arranged on the surface of the lithium electrode layer.
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| CN111969172A (en) * | 2020-07-30 | 2020-11-20 | 北京理工大学 | Air-stable long-acting reference electrode suitable for lithium battery |
| CN112054162A (en) * | 2020-09-16 | 2020-12-08 | 北京理工大学 | Packaging method of metal lithium reference electrode for lithium battery |
| CN114552133A (en) * | 2021-09-15 | 2022-05-27 | 万向一二三股份公司 | Preparation method of negative electrode tab of surface inert metal coating and lithium battery |
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| CN111969172A (en) * | 2020-07-30 | 2020-11-20 | 北京理工大学 | Air-stable long-acting reference electrode suitable for lithium battery |
| CN112054162A (en) * | 2020-09-16 | 2020-12-08 | 北京理工大学 | Packaging method of metal lithium reference electrode for lithium battery |
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