A method for preparing a lithium manganese dioxide battery

Abstract

The present invention discloses a method for preparing a lithium manganese dioxide battery with excellent low-temperature, high-current pulse discharge performance. The method comprises first uniformly mixing a manganese dioxide material, a lithium intercalation material, and a conductive agent, then adding a binder to form a self-supporting film. The film is then rolled and coated onto an aluminum current collector to form a positive electrode. The positive electrode, lithium negative electrode, lithium ion-conducting non-aqueous electrolyte, polyolefin separator, and aluminum-plastic film casing are then assembled into a battery cell. Finally, the lithium manganese dioxide battery cell is charged to deintercalate lithium ions from the lithium intercalation material into the lithium negative electrode, thereby obtaining a lithium manganese dioxide battery. The method has the advantage of significantly improving the pulse discharge performance of the resulting lithium manganese dioxide battery under low-temperature conditions.

Description

Technical Field

[0001] The present invention belongs to the technical field of lithium primary batteries, and in particular relates to a method for preparing a lithium manganese dioxide battery. Background Art

[0002] Lithium primary batteries have the advantages of high energy density, low self-discharge rate and long storage life. They are widely used in civilian fields such as smart meters, smart bank cards, electronic tags, automobile ETC, as well as military fields such as unmanned autonomous vehicles, submarines, buoys, and individual soldiers.

[0003] Lithium / manganese dioxide batteries are an important type of lithium primary battery system, boasting energy densities exceeding 300Wh / kg, annual self-discharge rates of less than 2%, a storage life of more than five years, and excellent safety and environmental adaptability. Their primary drawback is poor low-temperature performance, particularly under low-temperature, high-current pulse conditions. During initial discharge, they exhibit significant voltage hysteresis, resulting in excessive voltage drop and insufficient performance.

[0004] The main ways to improve the low-temperature, high-current pulse discharge performance of lithium / manganese dioxide batteries include metal oxide doping, process optimization, and conductive agent optimization. However, due to the poor conductivity of the manganese dioxide material itself, it is difficult to achieve good high-current pulse discharge performance under low-temperature conditions, especially below -20°C. Summary of the Invention

[0005] The purpose of the present invention is to address the shortcomings of existing lithium manganese dioxide batteries, which have poor low-temperature and high-current pulse performance, and to provide a method for preparing a lithium manganese dioxide battery to improve the high-current pulse discharge performance of the lithium manganese dioxide battery under low-temperature conditions, especially to increase the starting discharge voltage under the high-current pulse discharge voltage.

[0006] In order to achieve the above object, the technical solution adopted by the present invention to solve the technical problem is: a method for preparing a lithium manganese dioxide battery, comprising the following steps: 87-90g of manganese dioxide material, 2-5g of lithium intercalation material, and 2.5-3.5g of conductive agent are mixed evenly, and then 4.5-6.5g of binder is added to form a self-supporting film, which is heated and rolled to cover an aluminum current collector to obtain a positive electrode sheet with a thickness of 180mm, a length of 110mm, and a width of 76mm; a layer of copper foil is laminated on a 170μm thick lithium metal sheet as a current collector to obtain a lithium negative electrode sheet with a length of 112mm and a width of 74mm; the above-mentioned positive electrode sheet and lithium negative electrode sheet are mixed with a lithium ion conductive non-aqueous electrolyte, a polyolefin separator and an aluminum plastic film. The membrane shell is assembled into a battery cell: a polyethylene ceramic diaphragm is stacked on the positive electrode sheet, a negative electrode sheet is stacked on the polyethylene ceramic diaphragm, and then the positive electrode sheet is stacked and repeated in sequence. After the stacking is completed, the number of positive electrode, negative electrode and diaphragm layers is at least 5 to obtain positive and negative electrode current collectors, and then the positive and negative electrode current collectors are welded to the electrode tabs to obtain an electrode group. The electrode group is placed in an aluminum-plastic film shell, and the aluminum-plastic film is heat-sealed on the side. 45-50g of lithium perchlorate organic electrolyte is injected, and then the top or upper aluminum-plastic film shell is heat-sealed to obtain a lithium manganese dioxide battery cell; the lithium manganese dioxide battery cell is connected to a charger and discharger, and charged for 1 hour under the condition of a current of 0.2-0.35A to deintercalate lithium ions in the lithium intercalation material into the lithium negative electrode to obtain a lithium manganese dioxide battery.

[0007] In the preparation method of the lithium manganese dioxide battery, the manganese dioxide material is electrolytic manganese dioxide, and the manganese dioxide accounts for 82.86-93.75% of the mass of the self-supporting film.

[0008] The preparation method of a lithium manganese dioxide battery, wherein the lithium embedded material is LiCoO2, LiMn2O4, Li2TiO3, LiVO2, LiNi 1-x-y Co x Mn y O2(0<x<0.5, 0<y<0.5), LiNi 1-x-y Co x Al y O2 (0<x<0.5, 0<y<0.5), the lithium insertion material accounts for 1.9~5.21% of the mass of the self-supporting film.

[0009] In the preparation method of the lithium manganese dioxide battery, the conductive agent is one or more of carbon black, graphite, nano-carbon fiber, and caustic black, and the conductive agent accounts for 2.38-3.65% of the mass of the self-supporting film.

[0010] In the preparation method of the lithium manganese dioxide battery, the binder is one or both of polytetrafluoroethylene (PTFE) and styrene-butadiene rubber, and the binder accounts for 4.29-6.77% of the mass of the self-supporting film.

[0011] The beneficial effects of the present invention are as follows: compared with the prior art, the lithium manganese dioxide battery prepared according to the method of the present invention adopts a solvent-free positive electrode production process and utilizes the higher lithium ion conductivity of the lithium-intercalated material to improve the pulse discharge performance of the lithium manganese dioxide battery under low temperature conditions, and the starting discharge voltage under high current pulse discharge voltage is significantly improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 This is a schematic diagram of the structure of the positive electrode sheet according to Example 1 of the present invention;

[0013] Figure 2 This is a schematic diagram of the structure of the metallic lithium negative electrode in Example 1 of the present invention;

[0014] Figure 3 This is a schematic structural diagram of a lithium manganese dioxide battery according to Example 1 of the present invention. DETAILED DESCRIPTION

[0015] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Example 1

[0016] The method for preparing a lithium manganese dioxide battery in this embodiment includes the following steps.

[0017] 87g of manganese dioxide material, 5g of LiCoO2 material, 2g of carbon black and 1g of graphite conductive agent were mixed evenly and then 5g of PTFE binder was added to form a self-supporting film. The film was heated and rolled into a positive electrode sheet with a thickness of 180mm, a length of 110mm and a width of 76mm. Figure 1 shown.

[0018] A layer of copper foil is attached to a 170μm thick lithium metal sheet as a current collector to obtain a negative electrode sheet with a length of 112mm and a width of 74mm. Figure 2 shown.

[0019] A polyethylene ceramic diaphragm is stacked on the positive electrode sheet, and a negative electrode sheet is stacked on the diaphragm, and this process is repeated. After stacking, the number of positive, negative, and diaphragm layers is 5. The positive and negative electrode current collectors are then welded to the tabs 4 to form an electrode group. The electrode group is placed in an aluminum-plastic film casing, the sides of which are heat-sealed, 45g of lithium perchlorate organic electrolyte is injected, and the top aluminum-plastic film is heat-sealed to obtain a lithium manganese dioxide battery cell.

[0020] Connect the lithium manganese dioxide battery cell to the charger and discharge machine, charge it at 0.35A current for 1 hour, and the lithium ions in the lithium cobalt oxide will be deintercalated from the positive electrode to the surface of the metal lithium negative electrode to obtain a lithium manganese dioxide battery. Figure 3 shown.

[0021] The lithium manganese dioxide battery prepared according to Example 1 was kept at a low temperature of -20°C for 8 hours and then pulse-discharged at a rate of 5C. The initial discharge voltage reached 2.7V. Example 2

[0022] The method for preparing a lithium manganese dioxide battery in this embodiment includes the following steps.

[0023] 90g of manganese dioxide material, 3g of material, 1.5g of graphite and 1g of nano-carbon fiber conductive agent were mixed evenly, and then 4.5g of PTFE binder was added to form a self-supporting film, which was heated and rolled into a positive electrode sheet with a thickness of 180mm, a length of 110mm and a width of 76mm.

[0024] A layer of copper foil was laminated on a 170 μm thick lithium metal sheet as a current collector to obtain a negative electrode sheet with a length of 112 mm and a width of 74 mm.

[0025] A polyethylene ceramic diaphragm is stacked on the positive electrode sheet, and a negative electrode sheet is stacked on the diaphragm, and this process is repeated. After stacking, the number of positive, negative, and diaphragm layers is 5. The positive and negative electrode current collectors are then welded to the tabs 4 to form an electrode group. The electrode group is placed in an aluminum-plastic film casing, the sides of which are heat-sealed, 50g of lithium perchlorate organic electrolyte is injected, and the upper aluminum-plastic film is heat-sealed to obtain a lithium manganese dioxide battery cell.

[0026] The lithium manganese dioxide battery cell was connected to a charger and discharger and charged at a current of 0.2A for 1 hour. The lithium ions were deintercalated from the positive electrode to the surface of the metallic lithium negative electrode to obtain a lithium manganese dioxide battery.

[0027] The lithium manganese dioxide battery prepared according to Example 2 was kept at a low temperature of -20°C for 8 hours and then pulse-discharged at a rate of 5C, with an initial discharge voltage reaching 2.6V. Example 3

[0028] The method for preparing a lithium manganese dioxide battery in this embodiment includes the following steps.

[0029] 90g of manganese dioxide material, 2g of Li2TiO3 material, 2.0g of graphite and 1.5g of caustic black conductive agent were mixed evenly, and then 4.5g of PTFE and 2g of styrene-butadiene rubber binder were added to form a self-supporting film, which was then heated and rolled into a positive electrode sheet with a thickness of 180mm, a length of 110mm and a width of 76mm.

[0030] A layer of copper foil was laminated on a 170 μm thick lithium metal sheet as a current collector to obtain a negative electrode sheet with a length of 112 mm and a width of 74 mm.

[0031] A polyethylene ceramic diaphragm is stacked on the positive electrode sheet, and a negative electrode sheet is stacked on the diaphragm, and this process is repeated until the number of positive, negative, and diaphragm layers is at least 5. The positive and negative electrode current collectors are then welded to the tabs 4 to form an electrode group, which is then placed in an aluminum-plastic film housing, heat-sealed on the sides, and injected with 50g of lithium perchlorate organic electrolyte. The upper aluminum-plastic film is then heat-sealed to form a lithium manganese dioxide battery cell.

[0032] The lithium manganese dioxide battery cell was connected to a charger and discharger and charged for 1 hour at a current of 0.2A. The lithium ions in Li2TiO3 were deintercalated from the positive electrode to the surface of the metallic lithium negative electrode to obtain a lithium manganese dioxide battery.

[0033] The lithium manganese dioxide battery prepared according to Example 2 was kept at a low temperature of -20°C for 8 hours and then pulse-discharged at a rate of 5C, with an initial discharge voltage reaching 2.6V. Example 4

[0034] Except that Li2TiO3 material is replaced by LiVO2, the lithium insertion material is LiNi 1-x-y Co x Mn y O2 (0<x<0.5, 0<y<0.5), the rest remained the same as in Example 3. The lithium manganese dioxide battery prepared according to Example 4 was kept at a low temperature of -20°C for 8 hours and then pulse-discharged at a rate of 5C, with an initial discharge voltage reaching 2.6V. Example 5

[0035] Except that Li2TiO3 material is replaced by LiMn2O4, the lithium embedded material is LiNi 1-x-y Co x Al y Except for O2 (0<x<0.5, 0<y<0.5), the other parameters remain unchanged as in Example 3. The lithium manganese dioxide battery prepared according to Example 5 was kept at a low temperature of -20°C for 8 hours and then pulse-discharged at a rate of 5C, with an initial discharge voltage of 2.6V.

[0036] The above embodiments are merely illustrative of the principles and effects of the present invention, as well as some embodiments of its application. A person skilled in the art may make several modifications and improvements without departing from the inventive concept of the present invention, and all of these modifications and improvements fall within the scope of protection of the present invention.

Claims

1. A method for preparing a lithium manganese dioxide battery, characterized in that: Includes the following steps The manganese dioxide material, lithium intercalation material and conductive agent are mixed evenly and then a binder is added to form a self-supporting film, which is then heated and rolled onto an aluminum current collector to obtain a positive electrode sheet; A layer of copper foil is laminated on the lithium metal sheet as a current collector to obtain a lithium negative electrode sheet; The positive electrode sheet, the lithium negative electrode sheet, the lithium ion conductive non-aqueous electrolyte, the polyolefin separator and the aluminum-plastic film shell are assembled into a battery cell: a polyethylene ceramic separator is stacked on the positive electrode sheet, a negative electrode sheet is stacked on the polyethylene ceramic separator, and then the positive electrode sheet is stacked and repeated in sequence. After the stacking is completed, the number of positive electrode, negative electrode and separator layers is at least 5 to obtain positive and negative electrode current collectors, and then the positive and negative electrode current collectors are welded to the tabs to obtain an electrode group, the electrode group is placed in an aluminum-plastic film shell, the aluminum-plastic film is heat-sealed on the sides, lithium perchlorate organic electrolyte is injected, and then the aluminum-plastic film shell is heat-sealed to obtain a lithium manganese dioxide battery cell; The lithium manganese dioxide battery cell is connected to a charger and discharger for charging, so that the lithium ions in the lithium intercalation material are deintercalated into the lithium negative electrode to obtain a lithium manganese dioxide battery.

2. The method for preparing a lithium manganese dioxide battery according to claim 1, wherein: The manganese dioxide material is electrolytic manganese dioxide, and manganese dioxide accounts for 82.86-93.75% of the mass of the self-supporting film.

3. The method for preparing a lithium manganese dioxide battery according to claim 1, wherein: The lithium-intercalation material is LiCoO2, LiMn2O4, Li2TiO3, LiVO2, LiNi 1-x-y Co x Mn y O2(0<x<0.5, 0<y<0.5), LiNi 1-x- y Co x Al y O2 (0<x<0.5, 0<y<0.5), the lithium insertion material accounts for 1.9~5.21% of the mass of the self-supporting film.

4. The method for preparing a lithium manganese dioxide battery according to claim 1, 2 or 3, wherein: The conductive agent is one or more of carbon black, graphite, nano carbon fiber and caustic black, and the conductive agent accounts for 2.38-3.65% of the mass of the self-supporting film.

5. The method for preparing a lithium manganese dioxide battery according to claim 4, characterized in that: The binder is polytetrafluoroethylene (PTFE) and / or styrene-butadiene rubber, and the binder accounts for 4.29-6.77% of the mass of the self-supporting film.

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