Aquadag for alkaline battery and application of aquadag

Abstract

The invention discloses aquadag for an alkaline battery and application of the aquadag. The aquadag comprises the following raw materials in percentage by weight: 12-16% of graphite powder, 5-8% of conductive carbon black, 1-2% of graphene, 15-18% of epoxy resin, 30-50% of butanone and 10-20% of cyclohexanone. The preparation method of the aquadag comprises the following steps: (1) uniformly stirring butanone and cyclohexanone to obtain a composite solvent; (2) adding solid epoxy resin into the composite solvent, and stirring at 800-1000 rpm to completely dissolve the solid epoxy resin; (3) slowly adding graphite powder and conductive carbon black graphene into the composite solvent, and dispersing at a high speed of 1100-1200 rpm for 45-50 min to obtain a mixture; and (4) carrying out ball milling on the mixture, sieving with a 200-mesh sieve, and discharging to obtain the aquadag. The graphene is doped into the aquadag, so that the technical effect of improving the comprehensive performance of the battery is achieved.

Description

Technical Field

[0001] This invention relates to the field of alkaline manganese batteries, and more particularly to a graphite emulsion for alkaline batteries and its application. Background Technology

[0002] Alkaline batteries, such as alkaline zinc-manganese batteries, are among the most widely used power sources in modern portable electronic devices. One of the key processes in their manufacturing is coating the inner wall of the battery's steel casing with a graphite emulsion coating. This coating acts as a conductive bridge between the positive electrode ring and the steel casing, and its core function is to reduce contact resistance, ensuring efficient current collection and transmission, thereby directly affecting the battery's discharge performance, especially its high-current discharge capability.

[0003] Currently, the commonly used graphite emulsion coating formulations in the industry mainly contain natural or artificial graphite as conductive materials, supplemented with binders (such as sodium carboxymethyl cellulose, styrene-butadiene rubber latex, etc.) and dispersion media (usually methyl ethyl ketone). Although this traditional graphite emulsion coating meets basic conductivity requirements to a certain extent, with the increasing demands on battery performance from electronic devices, the inherent insufficient conductivity leading to high internal resistance has become increasingly prominent, becoming a bottleneck restricting further improvement in battery discharge performance.

[0004] To address the issue of insufficient conductivity, the industry has made some attempts at improvement. For example, by introducing graphite particles of different sizes for gradation, the filling density and conductivity of the coating can be improved; or small amounts of auxiliary conductive agents such as carbon black and acetylene black can be added to compensate for contact defects between graphite particles, thus constructing a more efficient conductive network. However, these improvements have limited effect on the construction of the conductive network, and there is still room and demand for further improvement in battery discharge performance, especially continuous high-current discharge performance. Summary of the Invention

[0005] The objective of this invention is to provide a graphite emulsion for alkaline batteries and its applications.

[0006] The technical solution to achieve the purpose of this invention is: a graphite emulsion for alkaline batteries, wherein the raw materials are composed of the following weight percentages: 12-16% graphite powder, 5-8% conductive carbon black, 1-2% graphene, 15-18% epoxy resin, 30-50% methyl ethyl ketone and 10-20% cyclohexanone; The method for preparing the graphite emulsion includes the following steps: (1) Stir the above butanone and cyclohexanone together to obtain a composite solvent; (2) Add solid epoxy resin to the composite solvent in step (1) and stir at 800-1000 rpm until it is completely dissolved; (3) Then slowly add the graphite powder and conductive carbon black graphene to the composite solvent and disperse at high speed of 1100-1200 rpm for 45-50 min to obtain a mixture; (4) The mixture from step (3) is ball-milled at a linear speed of 8-10 m / s for 60-80 min; then it is discharged through a 200-mesh sieve to obtain the graphite emulsion.

[0007] In battery conductive agents, graphite and graphene are a classic combination: micron-sized graphite forms the "main channel," undertaking long-distance, low-resistance charge transport; nano-sized graphene acts like "solder," forming flexible short bridges between graphite sheets, filling gaps and eliminating breaks. Their complementary dimensions and synergistic size create a dense, low-percolation-threshold, and highly resilient three-dimensional conductive network, reducing material usage while improving conductivity. Currently, graphene is used in the cathode material of alkaline batteries, and from a particle size distribution perspective, the ratio of graphite to graphene should ideally be controlled within the range of (2-3):1.

[0008] However, the application of graphene in graphite emulsions is still in its infancy. The inventors of this invention have, for the first time, incorporated graphene into graphite emulsions and used a combination of high-speed dispersion and ball milling to break down the π-π stacking between graphene sheets while simultaneously achieving a uniform distribution of graphene around graphite powder and conductive carbon black. At the same time, the inventors optimized the amount of graphene added based on the amount of graphite powder added, but found that when the graphite to graphene ratio was (2-4):1 (corresponding to 4-8% graphene), the overall performance of the battery did not improve when the resulting graphite emulsion was sprayed onto the inner wall of an alkaline battery steel casing. Only when the graphite to graphene ratio was above 6:1 did the overall battery performance show improvement. Therefore, the amounts of graphite powder and graphene added in this invention are controlled at 12-16% and 1-2%, respectively.

[0009] The second objective of this invention is to provide a method for applying the graphite emulsion for alkaline batteries described in the first objective, wherein the graphite emulsion is diluted with the composite solvent composed of butanone and cyclohexanone, and the final viscosity is controlled at 90-120 mPa·s, and then sprayed onto the inner surface of the battery steel shell using a carbon coating machine.

[0010] This invention breaks with convention by incorporating graphene into graphite emulsion, controlling the addition amounts of graphite powder and graphene to 10-15% and 1-2% respectively, and combining this with a dispersion process of "high-speed dispersion + ball milling", thereby improving the overall performance of the battery by more than 2%. Detailed Implementation

[0011] The following provides a detailed description of preferred embodiments of the graphite emulsion for alkaline batteries of the present invention and its applications.

[0012] A graphite emulsion for alkaline batteries has the following raw material weight percentage composition: 12-16% graphite powder, 5-8% conductive carbon black, 1-2% graphene, 15-18% epoxy resin, 30-50% methyl ethyl ketone (MEK), and 10-20% cyclohexanone. The method for preparing the graphite emulsion includes the following steps: (1) Stir the above butanone and cyclohexanone together to obtain a composite solvent; (2) Add solid epoxy resin to the composite solvent in step (1) and stir at 800-1000 rpm until it is completely dissolved; (3) Then slowly add the graphite powder and conductive carbon black graphene to the composite solvent and disperse at high speed of 1100-1200 rpm for 45-50 min to obtain a mixture; (4) The mixture from step (3) is ball-milled using 0.3 mm zirconium beads, with a linear speed controlled at 8-10 m / s for 60-80 min; then it is discharged through a 200-mesh sieve to obtain the graphite emulsion.

[0013] The graphite emulsion prepared above was diluted with the composite solvent composed of methyl ethyl ketone (MEK) and cyclohexanone, and the final viscosity was controlled at 90–120 mPa·s. It was then sprayed onto the inner surface of the steel casing of the alkaline battery using a carbon coating machine. Finally, it was assembled into a No. 5 alkaline battery product according to the general assembly process for alkaline batteries.

[0014] The inventors tested the battery performance with different amounts of graphene added according to the above-mentioned graphene formulation and manufacturing method. The test data are shown in Table 1 below: Table 1

[0015] As shown in Table 1, when graphene is incorporated into graphite emulsion and "high-speed dispersion + ball milling" is used to achieve uniform distribution of graphene around graphite powder and conductive carbon black, and the amount of graphene added is controlled at 1-2%, the overall performance of the battery is significantly improved.

[0016] The above description is merely an embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent transformations made based on the content of the present invention specification, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A graphite emulsion for alkaline batteries, characterized in that... The raw materials are composed of the following weight percentages: graphite powder 12-16%, conductive carbon black 5-8%, graphene 1-2%, epoxy resin 15-18%, methyl ethyl ketone 30-50%, and cyclohexanone 10-20%. The method for preparing the graphite emulsion includes the following steps: (1) Stir the above butanone and cyclohexanone together to obtain a composite solvent; (2) Add solid epoxy resin to the composite solvent in step (1) and stir at 800-1000 rpm until it is completely dissolved; (3) Then slowly add the graphite powder and conductive carbon black graphene to the composite solvent and disperse at high speed of 1100-1200 rpm for 45-50 min to obtain a mixture; (4) The mixture from step (3) is ball-milled at a linear speed of 8-10 m / s for 60-80 min; then it is discharged through a 200-mesh sieve to obtain the graphite emulsion.

2. The application of the graphite emulsion for alkaline batteries according to claim 1 in alkaline batteries, characterized in that: The graphite emulsion was diluted with the composite solvent composed of butanone and cyclohexanone, and the final viscosity was controlled at 90-120 mPa·s. Then, it was sprayed onto the inner surface of the battery steel shell using a carbon coating machine.

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