Battery negative electrode, preparation method, and battery

Abstract

A battery negative electrode, a preparation method, and a battery. Active substance, an active substance dissolution inhibitor, a composite hydrogen evolution inhibitor, a rare earth additive, a carbon-based conductive toughening agent and a polytetrafluoroethylene (PTFE) binder are used as raw materials. First, the active substance dissolution inhibitor, the composite hydrogen evolution inhibitor and the rare earth additive are uniformly mixed in a suspension, to ensure the dispersion uniformity; zinc powder and a certain amount of zinc oxide are then added to convert the suspension into viscous slurry; and next, the carbon-based conductive toughening agent is added, and the carbon-based conductive toughening agent is uniformly dispersed by utilizing the frictional shear force between the slurry and powder, to form a three-dimensional conductive network. A large number of dissolution / deposition reaction active sites can be provided for the zinc-based active substance, and the corrosion resistance of the zinc negative electrode is enhanced, improving the capacity and stability of the zinc negative electrode. In addition, in a semi-dry process, PTFE can be fiberized under the action of mechanical force, and the resulting mixture is in the form of a colloidal mass, resembling dough; the processability is high, the electrode sheet loading capacity is high, and the electrode structure is stable; the electrode sheet has excellent film-forming properties and controllable thickness; and the capacity and stability of the zinc negative electrode are improved.

Description

Battery negative electrode, preparation method and battery Technical Field

[0001] The present application relates to the technical field of battery materials, and in particular to a battery negative electrode, a preparation method and a battery. Background Art

[0002] With the global push for low-carbon energy, the booming development of electronic products such as electric vehicles, drones, and wearable devices has created a huge demand for high-energy-density and high-safety battery devices. Currently, the demand for lithium-ion batteries is rising exponentially, resulting in high material costs. Rechargeable aqueous nickel-zinc batteries, with their low-cost raw materials, high safety, and high energy density, have attracted significant attention from both academia and industry.

[0003] Nickel-zinc batteries (NiZn) suffer from active material dissolution in the negative electrode, which is also affected by hydrogen evolution, corrosion, and zinc dendrites. This results in low Coulombic efficiency, insufficient cycle life, and limited capacity. Therefore, there is an urgent need to inhibit active material dissolution and the corresponding side reactions to achieve high-performance Zn batteries.

[0004] Summary of the Invention

[0005] In view of this, it is necessary to provide a battery negative electrode, preparation method and battery with a three-dimensional conductive network, strong corrosion resistance, stable structure, high capacity and good cycle stability to address the problems of low electrode load, insufficient single electrode capacity and short cycle life.

[0006] To solve the above problems, this application adopts the following technical solutions:

[0007] One of the purposes of this application is to provide a method for preparing a battery negative electrode, comprising:

[0008] An active substance dissolution inhibitor, a composite hydrogen evolution inhibitor, and a rare earth additive are mixed to obtain an initial powder A;

[0009] Mixing the initial powder A with the first solvent and stirring to obtain a suspension B;

[0010] The suspension B, zinc powder and zinc oxide powder are mixed and stirred to obtain slurry C;

[0011] Mixing the slurry C with the carbon-based conductive toughening agent to obtain slurry D;

[0012] Continuously stirring the slurry D, the zinc oxide powder, and the second solvent to obtain slurry E;

[0013] The slurry E is mixed with PTFE and stirred to obtain micelle F;

[0014] The micelle F is extruded and molded to obtain the negative electrode.

[0015] In some embodiments, the mass percentage of the sum of the mass of zinc oxide and zinc, the active material dissolution inhibitor, the complex hydrogen evolution inhibitor, the rare earth additive, the carbon-based conductive toughening agent, and the polytetrafluoroethylene binder is 50% to 90%, 4% to 20%, 2% to 10%, 0.5% to 5%, 0.5% to 5%, or 3% to 10%.

[0016] In some embodiments, in the step of mixing the active material dissolution inhibitor, the complex hydrogen evolution inhibitor, and the rare earth additive to obtain the initial powder A, the active material dissolution inhibitor is one or both of strontium hydroxide and barium hydroxide; the complex hydrogen evolution inhibitor is a mixture of indium oxide, tin oxide, bismuth oxide, and aluminum oxide, and the mass ratio of indium oxide, tin oxide, bismuth oxide, and aluminum oxide is 4:3:2:1 or 2:2:1:1 or 3:3:3:1; the rare earth additive is two or more of gadolinium oxide, lanthanum oxide, niobium oxide, praseodymium oxide, scandium oxide, lutetium oxide, terbium oxide, europium oxide, ytterbium oxide, gallium oxide, germanium oxide, neodymium oxide, dysprosium oxide, thulium oxide, holmium oxide, and erbium oxide.

[0017] In some embodiments, in the step of mixing and stirring the initial powder A with the first solvent to obtain a suspension B and in the step of continuing to stir the slurry D, the zinc oxide powder and the second solvent to obtain a slurry E, the first solvent and the second solvent are at least one of ethanol and deionized water.

[0018] In some embodiments, the mass of the first solvent is 10% to 50% of the mass of the initial powder A, the mass of the second solvent is 20% to 50% of the mass of the initial powder A, and the total mass of the first solvent and the second solvent is 30% to 100% of the mass of the initial powder A.

[0019] In some embodiments, in the step of mixing and stirring the suspension B, zinc powder and zinc oxide powder to obtain slurry C, the mass of the zinc oxide accounts for 5% to 85% of the total mass ratio of zinc oxide.

[0020] In some embodiments, in the step of mixing and stirring the slurry C with a carbon-based conductive toughening agent to obtain slurry D, the carbon-based conductive toughening agent is one or more of chopped carbon fiber, chopped carbon fiber, hydrophilic carbon fiber, hydrophobic carbon fiber, homophase graphite, heterophase graphite, multi-walled carbon nanotubes, and single-walled carbon nanotubes, and the stirring time of the mixing and stirring is 10-60 min.

[0021] In some embodiments, the carbon-based conductive toughening agent is a carbon fiber with a length of 3-5 μm; and the stirring time is 20 minutes.

[0022] In some embodiments, the step of mixing and stirring the slurry E with PTFE to obtain micelle F specifically includes: adding PTFE to the slurry E and mixing and stirring, the PTFE molecular chains extend to form a fibrous three-dimensional network structure, thereby forming physical adhesion with the powder, until the surface of the material is no longer adhered, to obtain micelle F, the PTFE is an emulsion with a mass concentration of 5-60%, and the stirring time is 5 to 120 minutes.

[0023] In some embodiments, the step of extruding the micelle F to obtain the negative electrode specifically includes the following steps:

[0024] The gel mass F is squeezed into a sheet, and then graded and rolled on a roller press to obtain a negative electrode single sheet of a certain thickness. The negative electrode single sheet is placed on both sides of a current collector and double-sided rolled and compacted, and then cut to obtain a standard negative electrode sheet.

[0025] In some embodiments, the number of graded rolling is 3-12 times, the thickness of the negative electrode single sheet is 200-800 um, and the thickness of the negative electrode sheet obtained after double-sided rolling is 300-1600 um.

[0026] In some embodiments, the negative electrode current collector is one of tinned punched copper strip, tinned burred copper strip, diagonally stretched tinned copper mesh, galvanized punched copper strip, galvanized burred copper strip, and diagonally stretched galvanized copper mesh.

[0027] The second purpose of this application is to provide a battery negative electrode, which is prepared by the preparation method.

[0028] The third purpose of this application is to provide a battery, including the battery negative electrode.

[0029] This application adopts the above technical solution, and its beneficial effects are as follows:

[0030] The battery negative electrode, preparation method and battery provided by the present application are based on active material, active material dissolution inhibitor, complex hydrogen evolution inhibitor, rare earth additive, carbon-based conductive toughening agent and polytetrafluoroethylene binder as raw materials. The active material dissolution inhibitor, complex hydrogen evolution inhibitor and rare earth additive are first mixed evenly in a suspension to ensure their uniform dispersion. Then zinc powder and a certain amount of zinc oxide are added to convert the suspension into a viscous slurry. After that, the carbon-based conductive toughening agent is added and the friction shear force between the slurry powders is used to evenly disperse the carbon-based conductive toughening agent to form a three-dimensional conductive network, which can provide a large number of dissolution / deposition reaction active sites for the zinc-based active material and enhance the corrosion resistance of the zinc negative electrode, thereby improving the capacity and stability of the zinc negative electrode. In addition, during the semi-dry process, PTFE can be fiberized under mechanical force, and the obtained mixture is in the form of micelles, resembling dough; the process is strong in processability, the pole piece load is high, and the electrode structure is stable; the pole piece film forming property is excellent, and the pole piece thickness is controllable; the capacity and stability of the zinc negative electrode are improved. Moreover, the use of multiple compound additives can effectively alleviate the problems of active material dissolution, hydrogen evolution and corrosion, deformation and zinc dendrites of the zinc negative electrode, thereby increasing the capacity and cycle life of the battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following briefly introduces the drawings required for use in the embodiments of the present application or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0032] FIG1 is a flow chart of the steps of a method for preparing a battery negative electrode according to an embodiment of the present invention;

[0033] FIG2 is a cycle capacity curve of the nickel-zinc battery assembled in Example 2 of the present invention at room temperature of 25° C. and a current density of 1C.

[0034] FIG3 is a charge and discharge curve diagram of the nickel-zinc battery assembled in Example 2 of the present invention at room temperature of 25° C. and a current density of 1C. DETAILED DESCRIPTION

[0035] The following describes in detail embodiments of the present application, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present application, and should not be construed as limiting the present application.

[0036] In the description of this application, it should be understood that the terms "upper", "lower", "horizontal", "inside", "outside", etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on this application.

[0037] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. Throughout the description of this application, "plurality" means two or more, unless otherwise specifically defined.

[0038] In order to make the purpose, technical solutions and advantages of the present application more clearly understood, the present application will be further described in detail below by taking the multifunctional detection of atherosclerosis in blood vessels as an example, in combination with the accompanying drawings and embodiments.

[0039] Please refer to FIG1 , which is a flow chart of the steps of the method for preparing a battery negative electrode provided in an embodiment of the present application, including the following steps:

[0040] S110: mixing an active substance dissolution inhibitor, a composite hydrogen evolution inhibitor, and a rare earth additive to obtain an initial powder A.

[0041] In this embodiment, the active material dissolution inhibitor is one or both of strontium hydroxide and barium hydroxide; the complex hydrogen evolution inhibitor is a mixture of indium oxide, tin oxide, bismuth oxide, and aluminum oxide, and the mass ratio of indium oxide, tin oxide, bismuth oxide, and aluminum oxide is 4:3:2:1 or 2:2:1:1 or 3:3:3:1; the rare earth additive is two or more of gadolinium oxide, lanthanum oxide, niobium oxide, praseodymium oxide, scandium oxide, lutetium oxide, terbium oxide, europium oxide, ytterbium oxide, gallium oxide, germanium oxide, neodymium oxide, dysprosium oxide, thulium oxide, holmium oxide, and erbium oxide.

[0042] It can be understood that the use of multiple compound additives in this embodiment can effectively alleviate the problems of active material dissolution, hydrogen evolution and corrosion, deformation and zinc dendrites of the zinc negative electrode, thereby increasing the capacity and cycle life of the battery.

[0043] S120: Mixing and stirring the initial powder A with a first solvent to obtain a suspension B.

[0044] In this embodiment, the first solvent is at least one of ethanol and deionized water. The mass of the first solvent is 10% to 50% of the mass of the initial powder A.

[0045] S130: The suspension B, zinc powder and zinc oxide powder are mixed and stirred to obtain slurry C.

[0046] In this embodiment, the mass of the zinc oxide accounts for 5% to 85% of the total mass of the zinc oxide.

[0047] Furthermore, the mass of the zinc oxide accounts for 20% to 60% of the total mass ratio of zinc oxide.

[0048] It can be understood that the basis for the amount of zinc oxide added is to transform the suspension into a viscous slurry, so that the friction shear force between the slurry powders can be used to introduce the uniformly dispersed carbon-based conductive toughening agent.

[0049] S140: Mixing the slurry C with the carbon-based conductive toughening agent and stirring to obtain slurry D.

[0050] In this embodiment, the carbon-based conductive toughening agent is one or more of chopped carbon fiber, chopped carbon fiber, hydrophilic carbon fiber, hydrophobic carbon fiber, homogeneous graphite, heterogeneous graphite, multi-walled carbon nanotubes, and single-walled carbon nanotubes, and the mixing time is 10-60 minutes.

[0051] Furthermore, the carbon-based conductive toughening agent is a carbon fiber with a length of 3-5 μm; and the stirring time after adding the carbon-based conductive toughening agent is 20 minutes.

[0052] It can be understood that the uniformly dispersed carbon-based conductive toughening agent can form a three-dimensional conductive network inside the zinc negative electrode, which can provide a large number of dissolution / deposition reaction active sites for the zinc-based active substance. The zinc negative electrode has a large reactive surface area and many reactive active sites, so the capacity is improved; and the corrosion resistance of the zinc negative electrode is enhanced, and the dissolution / deposition of the zinc-based active substance is more uniform and reversible, so the stability is improved.

[0053] S150: Continuously stirring the slurry D, the zinc oxide powder, and the second solvent to obtain slurry E.

[0054] In this embodiment, the second solvent is at least one of ethanol and deionized water. The mass of the second solvent is 20% to 50% of the mass of the initial powder A, and the total mass of the first solvent and the second solvent is 30% to 100% of the mass of the initial powder A.

[0055] S160: The slurry E is mixed with PTFE (polytetrafluoroethylene) and stirred to obtain micelles F.

[0056] In this embodiment, the step of mixing and stirring the slurry E with PTFE to obtain micelle F specifically includes: adding PTFE to the slurry E and mixing and stirring, the PTFE molecular chains extend to form a fibrous three-dimensional network structure, thereby forming physical adhesion with the powder until the surface of the material is no longer adhered, and micelle F is obtained, the PTFE is an emulsion with a mass concentration of 60%, and the stirring time is 5 to 120 minutes.

[0057] Furthermore, the stirring time is 40 min.

[0058] It can be understood that during the semi-dry process, PTFE can be fiberized under the action of mechanical force, and the obtained mixture is in the form of colloids, similar to dough; the processability is strong, the electrode load is high, and the electrode structure is stable; the electrode film-forming property is excellent, and the electrode thickness is controllable; the capacity and stability of the zinc negative electrode are improved.

[0059] S170: Extruding the micelle F to obtain the negative electrode.

[0060] In this embodiment, the step of extruding the gel group F to obtain the negative electrode specifically includes the following steps: extruding the gel group F into a sheet, and then rolling it in a graded manner on a roller press to obtain a negative electrode single sheet of a certain thickness, placing the negative electrode single sheet on both sides of the current collector for double-sided rolling and compacting, and cutting to obtain a standard negative electrode sheet.

[0061] Specifically, the number of graded rolling presses is 3-12 times, the thickness of the negative electrode single sheet is 200-800 μm, and the thickness of the negative electrode sheet obtained after double-sided rolling presses is 300-1600 μm.

[0062] In this embodiment, the negative electrode current collector is one of tinned perforated copper strip, tinned burred copper strip, diagonally drawn tinned copper mesh, galvanized perforated copper strip, galvanized burred copper strip, and diagonally drawn galvanized copper mesh.

[0063] In this embodiment, the mass percentages of the sum of the mass of zinc oxide and zinc, the active material dissolution inhibitor, the complex hydrogen evolution inhibitor, the rare earth additive, the carbon-based conductive toughening agent, and the polytetrafluoroethylene binder are 50% to 90%, 4% to 20%, 2% to 10%, 0.5% to 5%, 0.5% to 5%, and 3% to 10%.

[0064] The battery negative electrode and preparation method provided in the above embodiment of the present application are based on active material, active material dissolution inhibitor, complex hydrogen evolution inhibitor, rare earth additive, carbon-based conductive toughening agent, and polytetrafluoroethylene binder as raw materials. The active material dissolution inhibitor, complex hydrogen evolution inhibitor, and rare earth additive are first mixed evenly in a suspension to ensure their uniform dispersion. Then, zinc powder and a certain amount of zinc oxide are added to convert the suspension into a viscous slurry. After that, the carbon-based conductive toughening agent is added, and the friction shear force between the slurry powders is used to evenly disperse the carbon-based conductive toughening agent to form a three-dimensional conductive network, which can provide a large number of dissolution / deposition reaction active sites for the zinc-based active material, and enhance the corrosion resistance of the zinc negative electrode, thereby improving the capacity and stability of the zinc negative electrode. In addition, during the semi-dry process, PTFE can be fiberized under mechanical force, and the obtained mixture is in the form of micelles, resembling dough; the process is strong in processability, the pole piece load is high, and the electrode structure is stable; the pole piece film forming property is excellent, and the pole piece thickness is controllable; the capacity and stability of the zinc negative electrode are improved. Moreover, the use of multiple compound additives can effectively alleviate the problems of active material dissolution, hydrogen evolution and corrosion, deformation and zinc dendrites of the zinc negative electrode, thereby increasing the capacity and cycle life of the battery.

[0065] The above technical solutions of the present application are described in detail below with reference to specific embodiments.

[0066] Example 1:

[0067] The active material dissolution inhibitor, the composite hydrogen evolution inhibitor, the rare earth additive and other solid powders are mixed in a mass ratio of 4%:8%:2% to obtain an initial powder A, wherein the composite hydrogen evolution inhibitor is added in a ratio of 2:2:1:1 of indium oxide, tin oxide, bismuth oxide and aluminum oxide. The powder A is mixed evenly with an ethanol solvent accounting for 25% of the total mass of the solid powder in a blender to obtain a suspension B. 4% zinc powder and 10% zinc oxide powder are slowly added and stirred evenly to obtain a suspension C containing a slurry. 1% carbon-based conductive toughening agent is added and stirred for 20 minutes. Since less solid active material is added and too much solvent is added, the dispersion of the carbon-based conductive toughening agent depends on the flow of the liquid. The carbon-based conductive toughening agent agglomerated together and dispersed poorly), similar to the wet mixing process, obtained a suspension D containing slurry, added the remaining 65% by mass of zinc oxide powder and 35% by mass of ethanol solvent of the total mass of solid powder and continued stirring to obtain slurry E, added 10% by mass of 60% PTFE emulsion and continued stirring for 40 minutes to extend the PTFE molecular chain to form a network structure and thus form physical adhesion with the powder until the surface is no longer adhered, to obtain a flocculent F, which was roller-pressed to obtain a negative electrode monolith with a thickness of 0.5 mm, and the negative electrode monolith was double-sidedly roller-compacted on both sides of the punched copper belt current collector, and cut to obtain a negative electrode sheet with a thickness of 0.7 mm.

[0068] Nickel-zinc battery assembly: The semi-dry process anode is coated with an anti-dendrite separator, stacked with a commercial spherical nickel cathode, and the tabs are welded. The battery is then packaged into a pouch cell to create an unfilled battery. An aqueous electrolyte containing 6 mol / L KOH is then injected, and the battery is vacuum-treated and allowed to stand for 2 hours to complete the nickel-zinc battery.

[0069] Example 2:

[0070] The active material dissolution inhibitor, the composite hydrogen evolution inhibitor, the rare earth additive and other solid powders were mixed in a mass ratio of 4%:8%:2% to obtain the initial powder A, wherein the composite hydrogen evolution inhibitor was added in a ratio of 2:2:1:1 of indium oxide, tin oxide, bismuth oxide and aluminum oxide. The powder A was mixed evenly with an ethanol solvent accounting for 25% of the total mass of the solid powder in a blender to obtain a suspension B. 4% zinc powder and 25% zinc oxide powder were slowly added and stirred evenly to obtain a viscous slurry C. 1% carbon-based conductive toughening agent was added and stirred for 20 minutes. The friction shear force between the slurry powders was used to disperse the carbon-based conductive toughening agent. The mixture was uniform, and no obvious agglomerated carbon fibers were observed in the slurry, indicating that a uniformly dispersed slurry D was obtained. The remaining 50% by mass of zinc oxide powder and 35% by mass of ethanol solvent of the total mass of the solid powder were added and stirred to obtain slurry E. 10% by mass of 60% PTFE emulsion was added and stirred for 40 min to extend the PTFE molecular chain to form a network structure, thereby forming physical adhesion with the powder until the surface was no longer adhered, and a flocculent F was obtained. The negative electrode monolith with a thickness of 0.5 mm was obtained by roller pressing. The negative electrode monolith was double-sidedly rolled and compacted on both sides of the punched copper belt current collector, and cut to obtain a negative electrode sheet with a thickness of 0.7 mm.

[0071] Nickel-zinc battery assembly: The semi-dry process anode is coated with an anti-dendrite separator, stacked with a commercial spherical nickel cathode, and the tabs are welded. The battery is then packaged into a pouch cell to create an unfilled battery. An aqueous electrolyte containing 6 mol / L KOH is then injected, and the battery is vacuum-treated and allowed to stand for 2 hours to complete the nickel-zinc battery.

[0072] Example 3:

[0073] The active material dissolution inhibitor, hydrogen evolution inhibitor, rare earth additive and other solid powders are mixed in a mass ratio of 4%:8%:2% to obtain initial powder A, wherein the composite hydrogen evolution inhibitor is added in a ratio of 4:3:2:1 of indium oxide, tin oxide, bismuth oxide and aluminum oxide. The powder A is mixed evenly with an ethanol solvent accounting for 25% of the total mass of the solid powder in a blender to obtain a suspension B. 4% zinc powder and 25% zinc oxide powder are slowly added and stirred evenly to obtain a viscous slurry C. 1% carbon-based conductive toughening agent is added and stirred for 20 minutes. The friction shear force between the slurry powders is used to disperse the carbon-based conductive toughening agent evenly. The mixture was stirred evenly until no obvious agglomerated carbon fibers were observed in the slurry, and a uniformly dispersed slurry D was obtained. The remaining 50% by mass of zinc oxide powder and 35% by mass of ethanol solvent of the total mass of the solid powder were added and stirred to obtain slurry E. 10% by mass of 60% PTFE emulsion was added and stirred for 40 min to extend the PTFE molecular chain to form a network structure, thereby forming physical adhesion with the powder until the surface was no longer adhered, and a gel group F was obtained. The negative electrode monolith with a thickness of 0.5 mm was obtained by roller pressing. The negative electrode monolith was double-sidedly rolled and compacted on both sides of the punched copper belt current collector, and cut to obtain a negative electrode sheet with a thickness of 0.7 mm.

[0074] Nickel-zinc battery assembly: The semi-dry process anode is coated with an anti-dendrite separator, stacked with a commercial spherical nickel cathode, and the tabs are welded. The battery is then packaged into a pouch cell to create an unfilled battery. An aqueous electrolyte containing 6 mol / L KOH is then injected, and the battery is vacuum-treated and allowed to stand for 2 hours to complete the nickel-zinc battery.

[0075] Example 4:

[0076] The active material dissolution inhibitor, hydrogen evolution inhibitor, rare earth additive and other solid powders are mixed in a mass ratio of 4%:8%:2% to obtain initial powder A, wherein the composite hydrogen evolution inhibitor is added in a ratio of 3:3:3:1 of indium oxide, tin oxide, bismuth oxide and aluminum oxide. Powder A is mixed evenly with ethanol solvent accounting for 25% of the total mass of the solid powder in a blender to obtain suspension B. 4% zinc powder and 25% zinc oxide powder are slowly added and stirred evenly to obtain a viscous slurry C. 1% carbon-based conductive toughening agent is added and stirred for 20 minutes. The friction shear force between the slurry powders is used to disperse the carbon-based conductive toughening agent evenly. The mixture was stirred evenly until no obvious agglomerated carbon fibers were observed in the slurry, and a uniformly dispersed slurry D was obtained. The remaining 50% by mass of zinc oxide powder and 35% by mass of ethanol solvent of the total mass of the solid powder were added and stirred to obtain slurry E. 10% by mass of 60% PTFE emulsion was added and stirred for 40 min to extend the PTFE molecular chain to form a network structure, thereby forming physical adhesion with the powder until the surface was no longer adhered, and a gel group F was obtained. The negative electrode monolith with a thickness of 0.5 mm was obtained by roller pressing. The negative electrode monolith was double-sidedly rolled and compacted on both sides of the punched copper belt current collector, and cut to obtain a negative electrode sheet with a thickness of 0.7 mm.

[0077] Nickel-zinc battery assembly: The semi-dry process anode is coated with an anti-dendrite separator, stacked with a commercial spherical nickel cathode, and the tabs are welded. The battery is then packaged into a pouch cell to create an unfilled battery. An aqueous electrolyte containing 6 mol / L KOH is then injected, and the battery is vacuum-treated and allowed to stand for 2 hours to complete the nickel-zinc battery.

[0078] Example 5:

[0079] The active material dissolution inhibitor, the composite hydrogen evolution inhibitor, the rare earth additive and other solid powders are mixed in a mass ratio of 4:8:2 to obtain the initial powder A, wherein the composite hydrogen evolution inhibitor is added in a ratio of 2:2:1:1 of indium oxide, tin oxide, bismuth oxide and aluminum oxide. The powder A is mixed evenly with a water solvent accounting for 25% of the total mass of the solid powder in a blender to obtain a suspension B. 4% zinc powder and 25% zinc oxide powder are slowly added and stirred evenly to obtain a viscous slurry C. 1% carbon-based conductive toughening agent is added and stirred for 20 minutes. The friction shear force between the slurry powders is used to disperse the carbon-based conductive toughening agent evenly. The mixture was stirred evenly until no obvious agglomerated carbon fibers were observed in the slurry, and a uniformly dispersed slurry D was obtained. The remaining 50% by mass of zinc oxide powder and 35% by mass of an aqueous solvent of the total mass of the solid powder were added and stirred continuously to obtain a slurry E. 10% by mass of a 60% PTFE emulsion was added and stirred continuously for 40 min to extend the PTFE molecular chains to form a network structure, thereby forming a physical adhesion with the powder, until the surface was no longer adhered, to obtain a gel group F. The negative electrode monolith with a thickness of 0.5 mm was obtained by roller pressing. The negative electrode monolith was double-sidedly rolled and compacted on both sides of the punched copper belt current collector, and cut to obtain a negative electrode sheet with a thickness of 0.7 mm.

[0080] Nickel-zinc battery assembly: The semi-dry process anode is coated with an anti-dendrite separator, stacked with a commercial spherical nickel cathode, and the tabs are welded. The battery is then packaged into a pouch cell to create an unfilled battery. An aqueous electrolyte containing 6 mol / L KOH is then injected, and the battery is vacuum-treated and allowed to stand for 2 hours to complete the nickel-zinc battery.

[0081] Comparative Example 1:

[0082] Without adding active substance dissolution inhibitor, the composite hydrogen evolution inhibitor, rare earth additive and other solid powders are mixed in a mass ratio of 8%:2% to obtain initial powder A, wherein the composite hydrogen evolution inhibitor is added in a ratio of 2:2:1:1 of indium oxide, tin oxide, bismuth oxide and aluminum oxide. Powder A is mixed evenly with ethanol solvent accounting for 25% of the total mass of the solid powder in a blender to obtain suspension B. 4% zinc powder and 25% zinc oxide powder are slowly added and stirred evenly to obtain a viscous slurry C. 1% carbon-based conductive toughening agent is added and stirred for 20 minutes. The friction shear force between the slurry powders is used to disperse the carbon-based conductive toughening agent. The mixture was uniform, and no obvious agglomerated carbon fibers were observed in the slurry, indicating that a uniformly dispersed slurry D was obtained. The remaining 50% by mass of zinc oxide powder and 35% by mass of ethanol solvent of the total mass of the solid powder were added and stirred to obtain slurry E. 10% by mass of 60% PTFE emulsion was added and stirred for 40 min to extend the PTFE molecular chain to form a network structure, thereby forming physical adhesion with the powder until the surface was no longer adhered, and a flocculent F was obtained. The negative electrode monolith with a thickness of 0.5 mm was obtained by roller pressing. The negative electrode monolith was double-sidedly rolled and compacted on both sides of the punched copper belt current collector, and cut to obtain a negative electrode sheet with a thickness of 0.7 mm.

[0083] Nickel-zinc battery assembly: The semi-dry process anode is coated with an anti-dendrite separator, stacked with a commercial spherical nickel cathode, and the tabs are welded. The battery is then packaged into a pouch cell to create an unfilled battery. An aqueous electrolyte containing 6 mol / L KOH is then injected, and the battery is vacuum-treated and allowed to stand for 2 hours to complete the nickel-zinc battery.

[0084] Comparative Example 2:

[0085] Without adding rare earth additives, the active material dissolution inhibitor, the composite hydrogen evolution inhibitor and other solid powders were mixed at a mass ratio of 4%:8% to obtain the initial powder A, wherein the composite hydrogen evolution inhibitor was added in a ratio of 2:2:1:1 of indium oxide, tin oxide, bismuth oxide and aluminum oxide. The powder A was mixed evenly with an ethanol solvent accounting for 25% of the total mass of the solid powder in a blender to obtain a suspension B. 4% zinc powder and 25% zinc oxide powder were slowly added and stirred evenly to obtain a viscous slurry C. 1% carbon-based conductive toughening agent was added and stirred for 20 minutes. The friction shear force between the slurry powders was used to disperse the carbon-based conductive toughening agent. The mixture was uniform, and no obvious agglomerated carbon fibers were observed in the slurry, indicating that a uniformly dispersed slurry D was obtained. The remaining 50% by mass of zinc oxide powder and 35% by mass of ethanol solvent of the total mass of the solid powder were added and stirred to obtain slurry E. 10% by mass of 60% PTFE emulsion was added and stirred for 40 min to extend the PTFE molecular chain to form a network structure, thereby forming physical adhesion with the powder until the surface was no longer adhered, and a flocculent F was obtained. The negative electrode monolith with a thickness of 0.5 mm was obtained by roller pressing. The negative electrode monolith was double-sidedly rolled and compacted on both sides of the punched copper belt current collector, and cut to obtain a negative electrode sheet with a thickness of 0.7 mm.

[0086] Nickel-zinc battery assembly: The semi-dry process anode is coated with an anti-dendrite separator, stacked with a commercial spherical nickel cathode, and the tabs are welded. The battery is then packaged into a pouch cell to create an unfilled battery. An aqueous electrolyte containing 6 mol / L KOH is then injected, and the battery is vacuum-treated and allowed to stand for 2 hours to complete the nickel-zinc battery.

[0087] According to Examples 1-5 and Comparative Examples 1-2, various types of negative electrode sheets with the same loading capacity and area were prepared, matched with the same positive electrode sheets and electrolytes, and assembled into nickel-zinc batteries according to the same assembly method. Charge and discharge tests were performed on them, and the test data are shown in Table 1.

[0088] As shown in Table 1, the zinc negative electrode prepared by the battery negative electrode and the semi-dry electrode manufacturing method provided by the present application shows good electrochemical performance when assembled into a nickel-zinc battery. In the preferred embodiment 2, the semi-dry process disperses the carbon-based conductive toughening agent evenly, and at the same time adds a certain amount of active dissolution inhibitor, rare earth additive and complex hydrogen evolution inhibitor. The initial surface capacity of the battery can reach 27.91 mAh / cm 2 ; However, the traditional mixing method used in Example 1 is similar to the wet process, which cannot generate solid-phase shear force to evenly disperse the carbon-based conductive toughening agent. The carbon-based conductive toughening agent cannot play a corresponding role but instead causes side reactions. This reflects the key role of the unique mixing method created by the present invention in effectively introducing the carbon-based conductive toughening agent.

[0089] In Examples 3-4, the performance of different ratios of the composite hydrogen evolution inhibitor was lower than that of the optimal example, confirming the effect of the optimal ratio of the composite hydrogen evolution inhibitor proposed by the present invention. The performance of the nickel-zinc battery obtained in Example 5 using water as a solvent was inferior to that of the nickel-zinc battery obtained in Example 2 using ethanol as a solvent, indicating the advantage of using alcohol as a solvent in the semi-dry method of the present invention.

[0090] In comparative example 1, the capacity after 200 cycles without adding active dissolution inhibitor is 468 mAh lower than that of the optimal example 2; in comparative example 2, the capacity after 200 cycles without adding rare earth additives is 437 mAh lower than that of the optimal example 2; this confirms the contribution of active material dissolution inhibitors and rare earth additives to the capacity and cycle life of nickel-zinc batteries.

[0091] It can be understood that the various technical features of the above-described embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the various technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0092] The above are merely preferred embodiments of the present application and only specifically describe the technical principles of the present application. These descriptions are intended only to explain the principles of the present application and should not be construed in any way as limiting the scope of protection of the present application. Based on the explanations herein, any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present application, as well as other specific implementations of the present application that can be conceived by those skilled in the art without inventive effort, shall be included within the scope of protection of the present application.

Claims

1. A method for preparing a battery negative electrode, characterized in that, Including: Mixing an active substance dissolution inhibitor, a composite hydrogen evolution inhibitor, and a rare earth additive to obtain an initial powder A; Mixing and stirring the initial powder A with a first solvent to obtain a suspension B; Mixing and stirring the suspension B, zinc powder, and zinc oxide powder to obtain a slurry C; Mixing and stirring the slurry C with a carbon-based conductive toughening agent to obtain a slurry D; Continuing to stir the slurry D, the zinc oxide powder, and the second solvent to obtain a slurry E; Mixing and stirring the slurry E with PTFE to obtain a micelle F; Extruding and molding the micelle F to obtain the negative electrode.

2. The method for preparing a battery negative electrode according to claim 1, characterized in that, The mass percentages of the sum of the mass of zinc oxide and zinc, the active substance dissolution inhibitor, the composite hydrogen evolution inhibitor, the rare earth additive, the carbon-based conductive toughening agent, and the polytetrafluoroethylene binder are 50% - 90%, 4% - 20%, 2% - 10%, 0.5% - 5%, 0.5% - 5%, and 3% - 10%.

3. The method for preparing a battery negative electrode according to claim 1, characterized in that, In the step of mixing an active substance dissolution inhibitor, a composite hydrogen evolution inhibitor, and a rare earth additive to obtain an initial powder A, the active substance dissolution inhibitor is one or both of strontium hydroxide or barium hydroxide; the composite hydrogen evolution inhibitor is a mixture of indium oxide, tin oxide, bismuth oxide, and aluminum oxide, and the mass ratio of indium oxide, tin oxide, bismuth oxide, and aluminum oxide is 4:3:2:1 or 2:2:1:1 or 3:3:3:1; the rare earth additive is two or more of gadolinium oxide, lanthanum oxide, niobium oxide, praseodymium oxide, scandium oxide, lutetium oxide, terbium oxide, europium oxide, ytterbium oxide, gallium oxide, germanium oxide, neodymium oxide, dysprosium oxide, thulium oxide, holmium oxide, and erbium oxide.

4. The method for preparing a battery negative electrode according to claim 1, characterized in that, In the step of mixing and stirring the initial powder A with a first solvent to obtain a suspension B and in the step of continuing to stir the slurry D, the zinc oxide powder, and the second solvent to obtain a slurry E, the first solvent and the second solvent are at least one of ethanol and deionized water.

5. The method for preparing a battery negative electrode according to claim 4, characterized in that, The mass of the first solvent is 10% - 50% of the mass of the initial powder A, the mass of the second solvent is 20% - 50% of the mass of the initial powder A, and the sum of the masses of the first solvent and the second solvent is 30% - 100% of the mass of the initial powder A.

6. The method for preparing a battery negative electrode according to claim 1, characterized in that, In the step of mixing and stirring the suspension B, zinc powder, and zinc oxide powder to obtain a slurry C, the mass of the zinc oxide accounts for 5% - 85% of the overall zinc oxide mass ratio.

7. The method for preparing a battery negative electrode according to claim 1, characterized in that, In the step of mixing and stirring the slurry C with a carbon-based conductive toughening agent to obtain a slurry D, the carbon-based conductive toughening agent is one or more of long-cut carbon fiber, short-cut carbon fiber, hydrophilic carbon fiber, hydrophobic carbon fiber, in-phase graphite, out-of-phase graphite, multi-walled carbon nanotube, and single-walled carbon nanotube, and the stirring time for the mixing and stirring is 10 - 60 min.

8. The method for preparing a battery negative electrode according to claim 7, characterized in that, The carbon-based conductive toughening agent is a carbon fiber with a length of 3 - 5 μm; the stirring time is 20 min.

9. The method for preparing a battery negative electrode according to claim 1, characterized in that, In the step of mixing and stirring the slurry E with PTFE to obtain a micelle F, it specifically includes: PTFE is added to the slurry E and mixed and stirred. The PTFE molecular chains are extended to form a fibrous three-dimensional network structure, thereby forming a physical adhesion with the powder until the surface of the material is not sticky, and the micelle F is obtained. The PTFE is an emulsion with a mass concentration of 5-60%, and the stirring time is 5-120 min.

10. The method for preparing a battery negative electrode according to claim 1, characterized in that, In the step of extruding the micelle F to obtain the negative electrode, the following steps are specifically included: The micelle F is extruded into a sheet, and then passed through a roller press for grading and rolling to obtain a negative electrode single sheet with a certain thickness. The negative electrode single sheet is placed on both sides of the current collector and subjected to double-sided rolling and compaction, and after cutting, a standard negative electrode plate is prepared.

11. The method for preparing a battery negative electrode according to claim 9, characterized in that, The number of times of grading and rolling is 3-12 times, the thickness of the negative electrode single sheet is 200-800 um, and the thickness of the negative electrode sheet obtained after double-sided rolling is 300-1600 um.

12. The method for preparing a battery negative electrode according to claim 9, characterized in that, The negative electrode current collector is one of a tin-plated punched copper strip, a tin-plated burr copper strip, a diagonal-tension tin-plated copper mesh, a zinc-plated punched copper strip, a zinc-plated burr copper strip, and a diagonal-tension zinc-plated copper mesh.

13. A battery negative electrode, characterized in that, Prepared by the preparation method according to any one of claims 1 to 11.

14. A battery, characterized in that, Including the battery negative electrode according to claim 12.

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