Zinc electrode material and preparation method thereof

Abstract

The invention discloses a zinc electrode material, which is composed of a zinc alloy material and fullerene in a mass ratio of (2-3):1, wherein the zinc alloy material comprises the following components by mass fraction: 8-30ppm of gallium, 80-260ppm of bismuth, 5-12ppm of tin, 0.5-0.8ppm of niobium, 1-4ppm of strontium, 4-8ppm of rare earth elements, and the remainder is inevitable impurity elements and zinc. The zinc electrode material disclosed by the invention has good electrochemical performance, good environmental protection, stable physical and chemical properties, and long service life.

Description

Technical Field

[0001] The present invention relates to the technical field of electrode materials, and in particular to a zinc electrode material and a preparation method thereof. Background Art

[0002] With the miniaturization of household appliances, instruments, mobile communication equipment, portable electronic devices and national defense equipment, people's demand for high specific energy batteries has increased rapidly. Zinc electrode batteries, as a common battery system, have the advantages of low price and high specific energy and are widely used in the field of small and medium-sized civilian mobile power sources. Zinc electrode batteries are batteries with zinc as electrodes, such as zinc / air batteries, zinc / nickel batteries, zinc / silver batteries, etc. Among them, the zinc electrode is one of the key components of zinc electrode batteries, and its performance and cycle life greatly limit the commercial application of zinc-based batteries. Therefore, it is imperative to develop zinc electrode materials with excellent comprehensive performance and performance stability.

[0003] At present, the commonly used zinc electrode materials are mainly Zn-Bi, Zn-In and other alloys. These zinc alloy electrode materials can only improve the performance of zinc electrodes in one or several aspects, but cannot improve the performance of zinc electrodes comprehensively. In addition, the high prices of Bi and In also increase the cost of zinc electrodes, which seriously limits the practical application of zinc electrode batteries. Other types of zinc electrode materials on the market also have more or less problems such as deformation and dendrites of active zinc, and their environmental protection, processability and corrosion resistance still need to be further improved.

[0004] In order to solve the above problems, Chinese invention patent CN1167154C discloses a new type of zinc electrode material, whose chemical composition is: Zn 100-x M x , wherein M is any one or a mixture of rare earth elements such as La, Ce, Pu, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, etc., 0.1≤x≤50, they can be Zn-rare earth metal compounds or solid solutions. The zinc electrode using the invention as the electrode material has excellent electrochemical properties, as well as high discharge capacity and cycle life. The invention also has the advantages of simple process, low cost, non-toxicity and pollution-free, and is particularly suitable for various secondary batteries with zinc as the negative electrode, such as zinc-nickel secondary batteries, zinc-manganese batteries, zinc-silver batteries, zinc-air and zinc-Na3Fe(CN)6. However, the rare earth metals used in the zinc electrode material are relatively expensive, and some rare earth elements are radioactive, and the environmental protection performance needs to be further improved.

[0005] It can be seen that the development of a zinc electrode material with good electrochemical properties, good environmental protection, stable physical and chemical properties, and long service life and its preparation method meets market demand, has broad market value and application prospects, and is of great significance to promoting the development of the zinc electrode battery field. Summary of the invention

[0006] The main purpose of the present invention is to provide a zinc electrode material with good electrochemical performance, good environmental protection, stable physical and chemical properties and long service life and a preparation method thereof.

[0007] To achieve the above purpose, the present invention provides a zinc electrode material, which is composed of a zinc alloy material and fullerene in a mass ratio of (2-3):1, wherein the zinc alloy material includes the following components by mass fraction: gallium 8-30ppm, bismuth 80-260ppm, tin 5-12ppm, niobium 0.5-0.8ppm, strontium 1-4ppm, rare earth elements 4-8ppm, and the balance is inevitable impurity elements and zinc.

[0008] Preferably, the rare earth element is a mixture of lanthanum, cerium, praseodymium and neodymium in a mass ratio of 1:1:(0.8-1.2):0.6.

[0009] Another object of the present invention is to provide a method for preparing the zinc electrode material, comprising the following steps:

[0010] Step S1, mixing the metal powders uniformly according to the mass fraction, and pressing the mixture into a sheet using a mold under a certain pressure;

[0011] Step S2, sealing in a stainless steel container, diffusing in an argon atmosphere at a certain temperature for 1-5 hours, and then cooling to room temperature;

[0012] Step S3, the zinc alloy material and fullerene prepared in step S2 are mixed evenly, ground and sieved, and then heat treated and cooled in sequence to obtain a zinc electrode material.

[0013] Preferably, the certain pressure in step S1 is 8-32 MPa.

[0014] Preferably, the certain temperature in step S2 is 380°C to 480°C.

[0015] Preferably, the mesh number of the grinding and sieving in step S3 is 100-300 meshes.

[0016] Preferably, the heat treatment in step S3 is as follows: firstly heating to 65-85°C at 2-5°C / min and keeping warm for 5-8h; then heating to 100-120°C at 4-6°C / min and keeping warm for 1-2h.

[0017] Preferably, the cooling method in step S3 is air cooling, air cooling or water cooling.

[0018] Due to the application of the above technical solution, the present invention has the following beneficial effects:

[0019] (1) The preparation method of the zinc electrode material disclosed in the present invention does not require special equipment or modification of the original production line, has low capital investment, simple process, convenient operation, high preparation efficiency and finished product qualification rate, and is suitable for continuous large-scale production.

[0020] (2) The zinc electrode material disclosed in the present invention is composed of a zinc alloy material and fullerene in a mass ratio of (2-3):1, wherein the zinc alloy material includes the following components by mass fraction: 8-30ppm gallium, 80-260ppm bismuth, 5-12ppm tin, 0.5-0.8ppm niobium, 1-4ppm strontium, 4-8ppm rare earth elements, and the remainder is inevitable impurity elements and zinc. By rationally selecting the components and their proportions, they can better interact with each other, giving the material excellent electrochemical properties, so that the final material product has good environmental protection, stable physical and chemical properties, and long service life.

[0021] (3) The zinc electrode material disclosed in the present invention improves the conductivity, reduces the corrosion current density, and inhibits the growth of zinc dendrites through the compounding of fullerenes and alloying with other elements, thereby significantly improving the performance of the zinc electrode and effectively reducing the expansion rate and battery leakage rate. DETAILED DESCRIPTION

[0022] The following description is used to disclose the present invention so that those skilled in the art can implement the present invention. The preferred embodiments described below are only examples, and those skilled in the art may think of other obvious variations.

[0023] Example 1

[0024] A zinc electrode material is composed of a zinc alloy material and fullerene in a mass ratio of 2:1, wherein the zinc alloy material comprises the following components by mass fraction: 8 ppm gallium, 80 ppm bismuth, 5 ppm tin, 0.5 ppm niobium, 1 ppm strontium, 4 ppm rare earth elements, and the remainder is unavoidable impurity elements and zinc.

[0025] The rare earth element is a mixture of lanthanum, cerium, praseodymium and neodymium in a mass ratio of 1:1:0.8:0.6.

[0026] A method for preparing the zinc electrode material comprises the following steps:

[0027] Step S1, mixing the metal powders uniformly according to the mass fraction, and pressing the mixture into a sheet using a mold under a certain pressure;

[0028] Step S2, sealing in a stainless steel container, diffusing in an argon atmosphere at a certain temperature for 1 hour, and then cooling to room temperature;

[0029] Step S3, the zinc alloy material and fullerene prepared in step S2 are mixed evenly, ground and sieved, and then heat treated and cooled in sequence to obtain a zinc electrode material.

[0030] The certain pressure in step S1 is 8 MPa; the certain temperature in step S2 is 380°C.

[0031] The mesh number of the grinding and sieving in step S3 is 100 mesh; the heat treatment in step S3 is specifically: first heating to 65°C at 2°C / min and keeping warm for 5 hours; then heating to 100°C at 4°C / min and keeping warm for 2 hours; the cooling method in step S3 is air cooling.

[0032] Example 2

[0033] A zinc electrode material is composed of a zinc alloy material and fullerene in a mass ratio of 2.2:1, wherein the zinc alloy material comprises the following components by mass fraction: 12 ppm gallium, 120 ppm bismuth, 8 ppm tin, 0.6 ppm niobium, 2 ppm strontium, 5 ppm rare earth elements, and the balance is unavoidable impurity elements and zinc.

[0034] The rare earth element is a mixture of lanthanum, cerium, praseodymium and neodymium in a mass ratio of 1:1:0.9:0.6.

[0035] A method for preparing the zinc electrode material comprises the following steps:

[0036] Step S1, mixing the metal powders uniformly according to the mass fraction, and pressing the mixture into a sheet using a mold under a certain pressure;

[0037] Step S2, sealing in a stainless steel container, diffusing in an argon atmosphere at a certain temperature for 2 hours, and then cooling to room temperature;

[0038] Step S3, the zinc alloy material and fullerene prepared in step S2 are mixed evenly, ground and sieved, and then heat treated and cooled in sequence to obtain a zinc electrode material.

[0039] The certain pressure in step S1 is 16 MPa; the certain temperature in step S2 is 400°C.

[0040] The mesh number of the grinding and sieving in step S3 is 150 mesh; the heat treatment in step S3 is specifically: first heating to 70°C at 3°C / min and keeping warm for 6 hours; then heating to 105°C at 4.5°C / min and keeping warm for 1.8 hours; the cooling method in step S3 is air cooling.

[0041] Example 3

[0042] A zinc electrode material is composed of a zinc alloy material and fullerenes in a mass ratio of 2.5:1, wherein the zinc alloy material comprises the following components by mass fraction: 20 ppm gallium, 200 ppm bismuth, 9 ppm tin, 0.65 ppm niobium, 2.5 ppm strontium, 6 ppm rare earth elements, and the remainder is unavoidable impurity elements and zinc.

[0043] The rare earth element is a mixture of lanthanum, cerium, praseodymium and neodymium in a mass ratio of 1:1:1:0.6.

[0044] A method for preparing the zinc electrode material comprises the following steps:

[0045] Step S1, mixing the metal powders uniformly according to the mass fraction, and pressing the mixture into a sheet using a mold under a certain pressure;

[0046] Step S2, sealing in a stainless steel container, diffusing in an argon atmosphere at a certain temperature for 3 hours, and then cooling to room temperature;

[0047] Step S3, the zinc alloy material and fullerene prepared in step S2 are mixed evenly, ground and sieved, and then heat treated and cooled in sequence to obtain a zinc electrode material.

[0048] The certain pressure in step S1 is 26 MPa; the certain temperature in step S2 is 430°C.

[0049] The mesh number of the grinding and sieving in step S3 is 200 mesh; the heat treatment in step S3 is specifically: first heating to 75°C at 3.5°C / min and keeping warm for 6.5h; then heating to 110°C at 5°C / min and keeping warm for 1.5h; the cooling method in step S3 is water cooling.

[0050] Example 4

[0051] A zinc electrode material is composed of a zinc alloy material and fullerene in a mass ratio of 2.8:1, wherein the zinc alloy material comprises the following components by mass fraction: 28 ppm gallium, 240 ppm bismuth, 11 ppm tin, 0.75 ppm niobium, 3.5 ppm strontium, 7 ppm rare earth elements, and the remainder is unavoidable impurity elements and zinc.

[0052] The rare earth element is a mixture of lanthanum, cerium, praseodymium and neodymium in a mass ratio of 1:1:1.1:0.6.

[0053] A method for preparing the zinc electrode material comprises the following steps:

[0054] Step S1, mixing the metal powders uniformly according to the mass fraction, and pressing the mixture into a sheet using a mold under a certain pressure;

[0055] Step S2, sealing in a stainless steel container, diffusing in an argon atmosphere at a certain temperature for 4 hours, and then cooling to room temperature;

[0056] Step S3, the zinc alloy material and fullerene prepared in step S2 are mixed evenly, ground and sieved, and then heat treated and cooled in sequence to obtain a zinc electrode material.

[0057] The certain pressure in step S1 is 28 MPa; the certain temperature in step S2 is 460°C.

[0058] The mesh number of the grinding and sieving in step S3 is 250 mesh; the heat treatment in step S3 is specifically: first heating to 80°C at 4.5°C / min and keeping warm for 7.5h; then heating to 115°C at 5.5°C / min and keeping warm for 1.2h; the cooling method in step S3 is air cooling.

[0059] Example 5

[0060] A zinc electrode material is composed of a zinc alloy material and fullerene in a mass ratio of 3:1, wherein the zinc alloy material comprises the following components by mass fraction: 30 ppm gallium, 260 ppm bismuth, 12 ppm tin, 0.8 ppm niobium, 4 ppm strontium, 8 ppm rare earth elements, and the remainder is unavoidable impurity elements and zinc.

[0061] The rare earth element is a mixture of lanthanum, cerium, praseodymium and neodymium in a mass ratio of 1:1:1.2:0.6.

[0062] A method for preparing the zinc electrode material comprises the following steps:

[0063] Step S1, mixing the metal powders uniformly according to the mass fraction, and pressing the mixture into a sheet using a mold under a certain pressure;

[0064] Step S2, sealing in a stainless steel container, diffusing in an argon atmosphere at a certain temperature for 1-5 hours, and then cooling to room temperature;

[0065] Step S3, the zinc alloy material and fullerene prepared in step S2 are mixed evenly, ground and sieved, and then heat treated and cooled in sequence to obtain a zinc electrode material.

[0066] The certain pressure in step S1 is 32 MPa; the certain temperature in step S2 is 480° C.; and the mesh number of the ground and sieved in step S3 is 300 meshes.

[0067] The heat treatment in step S3 is specifically as follows: firstly, the temperature is raised to 85°C at 5°C / min and kept at that temperature for 8 hours; then, the temperature is raised to 120°C at 6°C / min and kept at that temperature for 1 hour; and the cooling method in step S3 is air cooling.

[0068] Comparative Example 1

[0069] The present invention provides a zinc electrode material, the formula and preparation method of which are similar to those of Example 1, except that strontium and gallium are not added.

[0070] Comparative Example 2

[0071] The present invention provides a zinc electrode material, the formula and preparation method of which are similar to those of Example 1, except that no fullerene is added.

[0072] The zinc electrode material samples prepared in the above Examples 1-5 and Comparative Examples 1-2 were subjected to relevant performance tests. The test results are shown in Table 1. The test method is as follows:

[0073] (1) Corrosion resistance: The zinc electrode materials prepared in each example were immersed in an electrolyte (25 wt% zinc chloride, 2.0 wt% ammonium chloride, and the rest water) at 45°C for 60 hours. After being taken out, washed with water, and dried, the mass retention rate of the zinc material was weighed. The larger the value, the better the corrosion resistance.

[0074] (2) Expansion rate, battery leakage, and discharge performance: The zinc electrode material, sodium polyacrylate powder, indium oxide powder, and electrolyte prepared in each example were mixed in a mass ratio of 90:3.5:1.5:95, and stirred at a stirring speed of 2000 rpm for 60 minutes to form a zinc paste; then, the zinc pastes of each example were used to assemble LR6 batteries on an LR6 battery production line; the zinc pastes of each example were injected into plastic tubes, and liquid paraffin was injected on the zinc pastes after compaction, and the tubes were sealed, and the zinc paste height (H1) and the paraffin liquid level height (H2) were read; the plastic tubes were then placed in a constant temperature box at 90°C for 24 hours, taken out of the constant temperature box, cooled to room temperature, and the paraffin liquid level height (H3) was read. The expansion rate of the zinc paste was calculated according to the following formula: Expansion rate (%) = (H3-H2) / H1×100. 25 batteries of each example were placed in a 90℃ oven, and phenolphthalein indicator was dripped on the bottom of the negative electrode of the battery every 20 days to check whether the battery leaked. Under the condition of 25±2℃, the battery was discharged at 1500mW for 2 seconds, 650mW for 28 seconds, 10 times per hour, 24 hours per day, and the end voltage was 1.05V. The test results are listed in Table 1.

[0075] Table 1

[0076] project Corrosion resistance (%) Expansion rate (%) Number of leaking batteries Discharge times (times) Example 1 99.3 22.8 0 135 Example 2 99.6 22.3 0 137 Example 3 99.7 22.0 0 139 Example 4 99.9 21.7 0 140 Example 5 99.9 21.3 0 143 Comparative Example 1 96.8 25.9 1 122 Comparative Example 2 99.0 23.3 1 129

[0077] As can be seen from Table 1, the zinc electrode material disclosed in the embodiment of the present invention has better corrosion resistance, lower expansion rate and leakage rate, and better discharge performance than the comparative example product, which is the result of the synergistic effect of various formulas and preparation steps. The addition of strontium, gallium and fullerene is beneficial to improving the above properties.

[0078] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions only describe the principles of the present invention. The present invention may be subject to various changes and improvements without departing from the spirit and scope of the present invention. These changes and improvements fall within the scope of the present invention. The scope of protection claimed by the present invention is defined by the attached claims and their equivalents.

Claims

1. A zinc electrode material, characterized in that The invention is composed of a zinc alloy material and fullerene in a mass ratio of (2-3):1, wherein the zinc alloy material includes the following components in mass fraction: 8-30ppm of gallium, 80-260ppm of bismuth, 5-12ppm of tin, 0.5-0.8ppm of niobium, 1-4ppm of strontium, 4-8ppm of rare earth elements, and the remainder is inevitable impurity elements and zinc; the rare earth elements are a mixture of lanthanum, cerium, praseodymium and neodymium in a mass ratio of 1:1:(0.8-1.2):0.6; The method for preparing the zinc electrode material comprises the following steps: Step S1, mixing the metal powders uniformly according to the mass fraction, and pressing the mixture into a sheet using a mold under a certain pressure; Step S2, sealing in a stainless steel container, diffusing in an argon atmosphere at a certain temperature for 1-5 hours, and then cooling to room temperature; Step S3, the zinc alloy material and fullerene prepared in step S2 are mixed evenly, ground and sieved, and then heat treated and cooled in sequence to obtain a zinc electrode material.

2. The method for preparing a zinc electrode material according to claim 1, characterized in that: The certain pressure in step S1 is 8 to 32 MPa.

3. The method for preparing the zinc electrode material according to claim 1, characterized in that: The certain temperature in step S2 is 380°C to 480°C.

4. The method for preparing a zinc electrode material according to claim 1, characterized in that: The mesh number of the grinding and sieving in step S3 is 100-300 meshes.

5. The method for preparing a zinc electrode material according to claim 1, characterized in that: The heat treatment in step S3 is specifically as follows: firstly, the temperature is raised to 65-85°C at 2-5°C / min and kept at that temperature for 5-8h; then, the temperature is raised to 100-120°C at 4-6°C / min and kept at that temperature for 1-2h.

6. The method for preparing a zinc electrode material according to claim 1, characterized in that: The cooling method in step S3 is wind cooling, air cooling or water cooling.