Water-based miniature copper battery and preparation method thereof

Abstract

The invention discloses a lithium manganate battery comprising a spinel lithium manganate positive electrode, a copper negative electrode matched with the spinel lithium manganate positive electrode in shape, and a gel electrolyte spaced between the positive electrode and the negative electrode. A novel water-based copper battery system is designed, spinel lithium manganate with relatively high working voltage is used as a positive electrode, and is matched with a hydrogel electrolyte, so that the oxygen evolution problem of the spinel lithium manganate positive electrode under high voltage can be inhibited, and the crosstalk problem of positive and negative electrode ions can be effectively avoided; the miniature battery breaks through the voltage limitation of the existing copper battery, the discharge voltage can reach 1V, and a new implementation way is provided for high voltage of the miniature copper battery; based on large exchange current density of the copper negative electrode, dendritic crystals are not easy to generate, and the battery can be rapidly charged and discharged.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of copper battery, in particular to a water-based micro copper battery and a preparation method thereof. BACKGROUND

[0002] As a new type of secondary battery system, water-based copper battery has attracted much attention due to its abundant copper material resources, low cost and good electrochemical stability. The existing copper ion battery usually uses metal copper as the negative electrode to realize charge storage through copper deposition and dissolution reaction. The positive electrode materials are mostly Prussian blue and its analogues, layered transition metal oxides or some organic compounds. However, due to the limitation of copper ion electrochemical reaction potential and the potential level of existing positive electrode materials, the current copper ion battery system generally has a low working voltage, and the output voltage is usually concentrated in a relatively low voltage range, which is difficult to meet the application scenarios requiring high voltage output.

[0003] The copper tellurium battery system disclosed in patent CN115133109A has a working voltage of less than 0.15V. The copper iodine battery disclosed in patent CN118983616A also has a working voltage of about 0.3V. The above technical solutions reflect the technical bottleneck of current copper ion micro battery in voltage improvement, which has become one of the key factors restricting the energy density improvement and application expansion of copper ion battery. Therefore, how to introduce positive electrode materials with higher working potential to construct a copper ion battery system with high working voltage is still a technical problem to be solved in the field. SUMMARY

[0004] The present application provides a water-based micro copper battery and a preparation method thereof to solve the problems in the prior art. The water-based micro copper battery comprises a spinel lithium manganate positive electrode, a copper negative electrode and a gel electrolyte. The spinel lithium manganate positive electrode with high working voltage is used in combination with the hydrogel electrolyte to avoid oxygen evolution of the spinel lithium manganate in the water-based electrolyte and the problem of abnormal charging and discharging of the battery due to positive and negative electrode reaction crosstalk. The micro battery breaks through the voltage limitation of the existing copper battery and provides a new implementation approach for high voltage of the micro copper battery.

[0005] To solve the above technical problems, the present application provides a water-based micro copper battery in the first aspect, which comprises a spinel lithium manganate positive electrode, a copper negative electrode matching the shape of the spinel lithium manganate positive electrode and a gel electrolyte spaced between the positive electrode and the negative electrode; wherein,

[0006] The positive electrode reaction is: ;

[0007] The negative electrode reaction is: .

[0008] The application designs a new water-based copper battery system, uses spinel lithium manganate with a higher working voltage as a positive electrode, sets a hydrogel electrolyte to inhibit the oxygen evolution problem of the spinel lithium manganate positive electrode under high pressure and effectively avoid the ion cross-talk problem of the positive and negative electrodes, solves the problem that the spinel lithium manganate positive electrode is easy to evolve oxygen in the water-based battery system and the positive and negative electrode reaction cross-talk problem when the spinel lithium manganate positive electrode and the copper negative electrode are combined, the micro battery breaks through the voltage limitation of the existing copper battery, and the discharge voltage can reach 1V, which provides a new implementation approach for the high-voltage of the micro copper battery; meanwhile, the exchange current density of the copper negative electrode is large, and dendrites are not easy to generate, so that the battery can be quickly charged and discharged.

[0009] Further, the copper negative electrode is a copper sheet, a copper foil and a current collector coated with copper powder.

[0010] Further, the raw material components of the gel electrolyte include polyvinyl alcohol, copper salt, lithium salt and water.

[0011] Further, the copper salt is selected from one or more of copper sulfate, copper acetate, copper chloride and copper nitrate.

[0012] The lithium salt is selected from one or more of lithium acetate, lithium sulfate, lithium chloride and lithium nitrate.

[0013] Further, the spinel lithium manganate positive electrode and the copper negative electrode are interdigital electrodes.

[0014] The second aspect of the application provides a preparation method of the water-based micro copper battery of the first aspect, and the preparation method comprises the following steps:

[0015] S1, a slurry containing spinel lithium manganate is coated on a current collector, dried, rolled and laser cut into an interdigital shape to obtain a spinel lithium manganate positive electrode;

[0016] S2, an interdigital copper negative electrode matched with the spinel lithium manganate positive electrode is laser cut;

[0017] S3, under the condition of 80-90 DEG C, polyvinyl alcohol is dissolved in water, then copper salt and lithium salt are sequentially added to obtain a mixed solution;

[0018] S4, the spinel lithium manganate positive electrode and the copper negative electrode are crossed on a substrate, then the mixed solution is added dropwise in the crossing area, the mixed solution is naturally cooled into a gel to form a gel electrolyte, the positive and negative electrodes are insulated and separated, and the water-based micro copper battery is obtained after packaging.

[0019] Further, in S1, the slurry further includes a conductive agent and a binder.

[0020] Further, the conductive agent is selected from one or more of acetylene black, conductive carbon black, carbon nanotubes, activated carbon and carbon fibers.

[0021] The adhesive is selected from one or more of polytetrafluoroethylene, sodium carboxymethyl cellulose, polyvinylidene fluoride, and polyvinyl alcohol.

[0022] Furthermore, in S3, the concentrations of copper salt and lithium salt in the mixture are independently selected from 0.1-1M.

[0023] Furthermore, in S4, encapsulation is performed using a film selected from ethylene-octene copolymer film, polymethyl methacrylate film, or styrene-methyl methacrylate copolymer film.

[0024] The beneficial effects of this invention are:

[0025] This invention designs a novel aqueous copper battery system using spinel lithium manganese oxide, which has a high operating voltage, as the positive electrode, combined with a hydrogel electrolyte. This not only suppresses the oxygen evolution problem of the spinel lithium manganese oxide positive electrode under high voltage, but also effectively avoids the crosstalk problem between the positive and negative electrodes. This micro battery breaks through the voltage limit of existing copper batteries, with a discharge voltage of up to 1V, providing a new way to achieve high voltage in micro copper batteries.

[0026] This invention is based on the high exchange current density of the copper negative electrode, which is less prone to dendrite formation, and the battery can be charged and discharged quickly.

[0027] The battery system of this invention is simple, low-cost, and has a high operating voltage, showing promising prospects in the field of micro energy storage. Attached Figure Description

[0028] To more clearly illustrate the technical solution of the present invention, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0029] Figure 1 This is a charge-discharge curve of the micro copper battery obtained in Embodiment 1 of the present invention;

[0030] Figure 2 This is a charge-discharge cycle diagram of the micro copper battery obtained in Embodiment 1 of the present invention;

[0031] Figure 3 This is the charging curve of the micro copper battery obtained in Comparative Example 1 of the present invention. Detailed Implementation

[0032] The technical solution of the present invention will be clearly and completely described below with reference to specific embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0033] This embodiment relates to an aqueous micro copper battery, comprising a spinel lithium manganese oxide positive electrode, a copper negative electrode with a shape matching the spinel lithium manganese oxide positive electrode, and a gel electrolyte spaced between the positive and negative electrodes; wherein...

[0034] The positive electrode reaction is: ;

[0035] The negative electrode reaction is: .

[0036] This embodiment designs a novel aqueous copper battery system using spinel lithium manganese oxide, which has a high operating voltage, as the positive electrode. Addressing the issues of oxygen evolution in aqueous battery systems caused by spinel lithium manganese oxide positive electrodes and crosstalk between positive and negative electrode reactions when combined with a copper negative electrode, a hydrogel electrolyte is incorporated. This not only suppresses oxygen evolution at high voltage but also effectively avoids crosstalk between positive and negative electrode ions. It breaks through the voltage limitations of existing copper batteries, achieving a discharge voltage of up to 1V, providing a new pathway for high-voltage micro-copper batteries. Furthermore, due to the high exchange current density of the copper negative electrode, dendrite formation is less likely, allowing for rapid charging and discharging of the battery.

[0037] In a preferred embodiment, the copper negative electrode is a current collector for copper sheets, copper foils, and copper powder coatings, and the spinel lithium manganese oxide positive electrode and the copper negative electrode are interdigitated electrodes.

[0038] In a preferred embodiment, the raw material components of the gel electrolyte include polyvinyl alcohol, copper salt, lithium salt and water; the copper salt is selected from one or more of copper sulfate, copper acetate, copper chloride and copper nitrate; the lithium salt is selected from one or more of lithium acetate, lithium sulfate, lithium chloride and lithium nitrate.

[0039] Another embodiment provides a method for preparing the aqueous micro copper battery described in the above embodiments, comprising the following steps:

[0040] S1. A slurry containing spinel lithium manganese oxide is coated onto a current collector, dried, rolled, and laser-cut into an interdigitated shape to obtain a spinel lithium manganese oxide cathode.

[0041] S2. Laser cutting of an interdigitated copper anode that matches the spinel lithium manganese oxide cathode;

[0042] S3. After dissolving polyvinyl alcohol in water at 80-90℃, copper salt and lithium salt are added sequentially to obtain a mixed solution.

[0043] S4. The spinel lithium manganese oxide positive electrode and the copper negative electrode are crossed on the substrate, and then the mixture is dropped into the cross region. The mixture is cooled to form a gel electrolyte that insulates and separates the positive and negative electrodes. After encapsulation, the aqueous micro copper battery is obtained.

[0044] In a preferred embodiment, in S1, the slurry further includes a conductive agent and a binder; the conductive agent is selected from one or more of acetylene black, conductive carbon black, carbon nanotubes, activated carbon and carbon fibers; the binder is selected from one or more of polytetrafluoroethylene, sodium carboxymethyl cellulose, polyvinylidene fluoride and polyvinyl alcohol.

[0045] In a preferred embodiment, in S3, the concentrations of copper salt and lithium salt in the mixture are independently selected from 0.1-1M.

[0046] In a preferred embodiment, in S4, encapsulation is performed using a film selected from ethylene-octene copolymer film, polymethyl methacrylate film, or styrene-methyl methacrylate copolymer film.

[0047] Example 1

[0048] This embodiment relates to a method for preparing an aqueous micro copper battery, comprising the following steps:

[0049] (1) Disperse spinel lithium manganese oxide, conductive carbon black and polyvinylidene fluoride in N-methylpyrrolidone at a mass ratio of 7:2:1, stir evenly to form a slurry, then coat it on the current collector, dry it, and then roll and laser cut it into interdigital shapes to obtain the positive electrode.

[0050] (2) The copper sheet is cut into interdigitated electrode sheets that match the shape of the positive electrode using a laser to obtain the negative electrode.

[0051] (3) At 85°C, polyvinyl alcohol and water are mixed in a mass ratio of 1:1, and 0.2M copper sulfate and 0.2M lithium sulfate are added in sequence to obtain a mixed solution.

[0052] (4) Cross the interdigitated positive and negative electrodes on the polyethylene terephthalate substrate, then drop the mixture obtained in step (3) onto the cross area, cool it to form a gel, and then insulate the positive and negative electrodes. Finally, seal the micro battery with an ethylene-octene copolymer film to obtain an aqueous micro copper battery, and perform performance testing. Figure 1 and Figure 2 The figures show the charge-discharge curves and charge-discharge cycle diagrams of the battery obtained in Example 1, where the micro copper battery has a discharge voltage of approximately 1.0V and a discharge capacity of 0.40 mAh cm⁻¹.-2 Furthermore, it can cycle stably for 50 cycles without capacity decay at a current density of 1C.

[0053] Example 2

[0054] This embodiment relates to a method for preparing an aqueous micro copper battery, comprising the following steps:

[0055] (1) Disperse spinel lithium manganese oxide, activated carbon and polyvinylidene fluoride in N-methylpyrrolidone at a mass ratio of 7:2:1, stir evenly to form a slurry, then coat it on the current collector, dry it and then roll and laser cut it into interdigital shape to obtain the positive electrode.

[0056] (2) The copper foil is cut into interdigitated electrode sheets that match the shape of the positive electrode using a laser to obtain the negative electrode.

[0057] (3) At 85°C, polyvinyl alcohol and water are mixed in a mass ratio of 1:1, and 0.5M copper nitrate and 0.5M lithium nitrate are added in sequence to obtain a mixture.

[0058] (4) Interdigitated positive and negative electrodes were crossed on a polyethylene terephthalate substrate. The mixture obtained in step (3) was then dropped onto the crossed area. After cooling and forming a gel, the positive and negative electrodes were insulated and separated. Finally, a polymethyl methacrylate film was used to seal the micro-battery, resulting in an aqueous micro-copper battery, and its performance was tested. The micro-copper battery obtained in Example 2 had a discharge voltage of approximately 1.0V and a discharge capacity of 0.38 mAh cm⁻¹. -2 Furthermore, it can cycle stably for 50 cycles without capacity decay at a current density of 1C.

[0059] Example 3

[0060] This embodiment relates to a method for preparing an aqueous micro copper battery, comprising the following steps:

[0061] (1) Disperse spinel lithium manganese oxide, carbon nanotubes and polyvinylidene fluoride in N-methylpyrrolidone at a mass ratio of 7:2:1, stir evenly to form a slurry, then coat it on the current collector, dry it, and then roll and laser cut it into interdigital shapes to obtain the positive electrode.

[0062] (2) The copper foil is cut into interdigitated electrode sheets that match the shape of the positive electrode using a laser to obtain the negative electrode.

[0063] (3) At 85°C, polyvinyl alcohol and water are mixed in a mass ratio of 1:1, and 0.5M copper chloride and 0.5M lithium chloride are added in sequence to obtain a mixture.

[0064] (4) Interdigitated positive and negative electrodes were crossed on a polyethylene terephthalate substrate. The mixture obtained in step (3) was then dropped onto the crossed area. After cooling and forming a gel, the positive and negative electrodes were insulated and separated. Finally, the micro battery was sealed with a styrene-methyl methacrylate copolymer film to obtain an aqueous micro copper battery, and its performance was tested. The micro copper battery obtained in Example 3 had a discharge voltage of approximately 1.0V and a discharge capacity of 0.41 mAh cm⁻¹. -2 Furthermore, it can cycle stably for 50 cycles without capacity decay at a current density of 1C.

[0065] Comparative Example 1

[0066] The difference between this comparative example and Example 3 is that a gel electrolyte is not used. Specifically, the steps include the following:

[0067] (1) Disperse spinel lithium manganese oxide, carbon nanotubes and polyvinylidene fluoride in N-methylpyrrolidone at a mass ratio of 7:2:1, stir evenly to form a slurry, then coat it on the current collector, dry it, and then roll and laser cut it into interdigital shapes to obtain the positive electrode.

[0068] (2) The copper foil is cut into interdigitated electrode sheets that match the shape of the positive electrode using a laser to obtain the negative electrode.

[0069] (3) Use a mixed solution of 0.5M copper chloride and 0.5M lithium chloride as the electrolyte;

[0070] (4) Separate the positive and negative electrodes with a glass fiber diaphragm, add 120uL of electrolyte, assemble into a button cell, and perform performance testing. Figure 3 The charging curve of the battery obtained in this comparative example shows that due to the severe oxygen evolution side reaction of the liquid electrolyte, the battery voltage is difficult to increase further after charging to 0.7V, thus preventing the battery from operating normally.

[0071] Comparative Example 2

[0072] The difference between this comparative example and Example 3 is that the positive electrode material does not use spinel lithium manganese oxide. Specifically, the steps include the following:

[0073] This embodiment relates to a method for preparing an aqueous micro copper battery, comprising the following steps:

[0074] (1) Copper sulfide, carbon nanotubes and polyvinylidene fluoride are dispersed in N-methylpyrrolidone at a mass ratio of 7:2:1, stirred evenly to form a slurry, then coated on the current collector, dried and then rolled and laser-cut into interdigitated shapes to obtain the positive electrode.

[0075] (2) The copper foil is cut into interdigitated electrode sheets that match the shape of the positive electrode using a laser to obtain the negative electrode.

[0076] (3) At 85°C, polyvinyl alcohol and water are mixed in a mass ratio of 1:1, and 0.5M copper chloride and 0.5M lithium chloride are added in sequence to obtain a mixture.

[0077] (4) Interdigitated positive and negative electrodes were crossed on a polyethylene terephthalate substrate. The mixture obtained in step (3) was then dropped onto the crossed area. After cooling and forming a gel, the positive and negative electrodes were insulated and separated. Finally, the micro battery was sealed with a styrene-methyl methacrylate copolymer film to obtain an aqueous micro copper battery, and its performance was tested. The discharge plateau voltage was 0.2V. This is because the voltage at which copper sulfide converts to cuprous sulfide is relatively low, resulting in a low discharge plateau voltage.

[0078] Comparative Example 3

[0079] The difference between this comparative example and Example 3 is that the interdigitated electrodes are not cut. Specifically, the steps include the following:

[0080] (1) Disperse spinel lithium manganese oxide, carbon nanotubes and polyvinylidene fluoride in N-methylpyrrolidone at a mass ratio of 7:2:1, stir evenly to form a slurry, then coat it on the current collector, dry it, and then roll and laser cut it into a circle with a radius of 6 mm to obtain the positive electrode.

[0081] (2) Cut the copper foil into a circle with the same shape as the positive electrode using a laser to obtain the negative electrode.

[0082] (3) At 85°C, polyvinyl alcohol and water were mixed in a mass ratio of 1:1, and 0.5M copper chloride and 0.5M lithium chloride were added in sequence. After cooling, a gel electrolyte was obtained.

[0083] (4) A positive electrode, gel electrolyte, and negative electrode were stacked on a polyethylene terephthalate substrate, and finally the micro battery was sealed with a styrene-methyl methacrylate copolymer film to obtain an aqueous micro copper battery, and its performance was tested. The battery capacity was 0.2 mAh cm⁻¹. -2 This is because without interdigitated electrodes, the contact area of ​​the active material is smaller, making it difficult to fully utilize some of the active material, resulting in lower capacity.

[0084] In summary, this invention designs a novel aqueous copper battery system using a spinel lithium manganese oxide cathode with a high operating voltage, combined with a hydrogel electrolyte. This not only suppresses oxygen evolution at the spinel lithium manganese oxide cathode under high voltage but also effectively avoids crosstalk between the positive and negative electrodes. It breaks through the voltage limitations of existing copper batteries, achieving a discharge voltage of up to 1V, providing a new approach to achieving high voltage in micro copper batteries. Due to the high exchange current density of the copper negative electrode, dendrite formation is less likely, allowing for rapid charge and discharge of the battery.

[0085] The present invention has been described in detail above with reference to specific embodiments and exemplary examples; however, these descriptions should not be construed as limiting the present invention. Those skilled in the art will understand that various equivalent substitutions, modifications, or improvements can be made to the technical solutions and embodiments of the present invention without departing from the spirit and scope of the invention, and all such modifications and improvements fall within the scope of the present invention. The scope of protection of the present invention is defined by the appended claims.

Claims

1. A water-based micro copper battery, characterized in that, It includes a spinel lithium manganese oxide positive electrode, a copper negative electrode with a shape matching the spinel lithium manganese oxide positive electrode, and a gel electrolyte spaced between the positive and negative electrodes; wherein, The positive electrode reaction is: ; The negative electrode reaction is: .

2. The aqueous micro copper battery as described in claim 1, characterized in that, The copper negative electrode is selected from copper sheets, copper foils, and current collectors coated with copper powder.

3. The aqueous micro copper battery as described in claim 1, characterized in that, The raw material components of the gel electrolyte include polyvinyl alcohol, copper salt, lithium salt and water.

4. The aqueous micro copper battery as described in claim 3, characterized in that, The copper salt is selected from one or more of copper sulfate, copper acetate, copper chloride, and copper nitrate; The lithium salt is selected from one or more of lithium acetate, lithium sulfate, lithium chloride, and lithium nitrate.

5. The aqueous micro copper battery as described in claim 1, characterized in that, The spinel lithium manganese oxide positive electrode and the copper negative electrode are interdigitated electrodes.

6. A method for preparing an aqueous micro copper battery according to any one of claims 1-5, characterized in that, Includes the following steps: S1. A slurry containing spinel lithium manganese oxide is coated onto a current collector, dried, rolled, and laser-cut into an interdigitated shape to obtain a spinel lithium manganese oxide cathode. S2. Laser cutting of an interdigitated copper anode that matches the spinel lithium manganese oxide cathode; S3. After dissolving polyvinyl alcohol in water at 80-90℃, copper salt and lithium salt are added sequentially to obtain a mixed solution. S4. The spinel lithium manganese oxide positive electrode and the copper negative electrode are crossed on the substrate, and then the mixture is dropped into the cross area. The mixture is naturally cooled to form a gel electrolyte that insulates and separates the positive and negative electrodes. After encapsulation, the aqueous micro copper battery is obtained.

7. The method for preparing an aqueous micro copper battery as described in claim 6, characterized in that, In S1, the slurry also includes a conductive agent and a binder.

8. The method for preparing an aqueous micro copper battery as described in claim 7, characterized in that, The conductive agent is selected from one or more of acetylene black, conductive carbon black, carbon nanotubes, activated carbon, and carbon fiber. The adhesive is selected from one or more of polytetrafluoroethylene, sodium carboxymethyl cellulose, polyvinylidene fluoride, and polyvinyl alcohol.

9. The method for preparing an aqueous micro copper battery as described in claim 6, characterized in that, In S3, the concentrations of copper salt and lithium salt in the mixture are independently selected from 0.1-1M.

10. The method for preparing an aqueous micro copper battery as described in claim 6, characterized in that, In S4, encapsulation is performed using a film selected from ethylene-octene copolymer film, polymethyl methacrylate film, or styrene-methyl methacrylate copolymer film.

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