A lithium thionyl chloride primary battery and its preparation method

Abstract

This invention provides a lithium thionyl chloride primary battery and its preparation method. The lithium thionyl chloride primary battery includes a lithium metal anode, a separator, a cathode, and a thionyl chloride electrolyte; wherein, the surface of the lithium metal anode is coated with a nano-metal coating and / or the thionyl chloride electrolyte includes a phthalocyanine metal complex. In this invention, the nano-metal coating protects the lithium metal anode from corrosion by thionyl chloride, prevents self-discharge during storage or idle periods of intermittent discharge, and promotes lithium-ion migration to the cathode; the phthalocyanine metal complex optimizes the reduction reaction of thionyl chloride, increasing the battery's discharge voltage, while reducing the electrolyte resistance, thus improving the high-current discharge performance of the lithium thionyl chloride primary battery. Therefore, this lithium thionyl chloride primary battery can respond quickly when discharge is needed, and does not experience capacity loss when discharge is not required, thereby increasing the overall discharge capacity of the battery.

Description

Technical Field

[0001] This invention belongs to the field of primary battery technology, specifically relating to a lithium thionyl chloride primary battery and its preparation method. Background Technology

[0002] Lithium thionyl chloride primary batteries are non-rechargeable batteries, involving only the discharge reaction. The overall discharge electrochemical reaction is as follows: 2SOCl₂ + 4Li → 4LiCl + SO₂ + S. Here, SOCl₂ is thionyl chloride, a liquid positive electrode component that also serves as the electrolyte (positive electrode electrolyte), contained in the porous carbon electrode or positive electrode current collector; Li is the lithium negative electrode, and also the negative terminal of the battery. The overall discharge electrochemical reaction consists of two half-reaction equations, which occur at the lithium negative electrode (Li → Li₂). + +e) and the positive electrode (2SOCl2+4Li) + +4e→4LiCl+SO2+S). Therefore, during discharge, the lithium anode discharges to generate lithium ions and electrons. Electrons flow to the positive electrode of the battery through the external circuit, while lithium ions move inside the battery. At the positive electrode, thionyl chloride undergoes a reduction reaction after accepting electrons from the external circuit and lithium ions from the electrolyte.

[0003] However, besides the discharge reaction occurring at the positive electrode as required for discharge, the lithium anode can also react on the lithium surface due to direct contact with the thionyl chloride cathode electrolyte within the battery. This reaction triggers corrosion and leads to self-discharge as it continuously consumes the cathode electrolyte and lithium metal. Under normal circumstances, when this reaction occurs on the lithium metal surface, a lithium chloride layer is deposited. This lithium chloride layer, originating from the initial corrosion reaction, has a passivating effect on the lithium metal, inhibiting further rapid corrosion; hence, it is called a passivation layer. However, the naturally formed passivation layer on the lithium metal surface has defects: on the one hand, it increases the impedance of subsequent battery discharge; on the other hand, this layer cannot provide complete corrosion protection for the lithium metal. Therefore, during long-term storage or operation, self-discharge continues, ultimately leading to a significant decrease in battery discharge capacity.

[0004] Furthermore, when a lithium thionyl chloride primary battery is discharged at a high discharge current, the discharge limitation often occurs on the positive electrode side due to the low efficiency of the electrochemical process of thionyl chloride reduction, which affects the discharge performance of the battery.

[0005] Therefore, how to further improve the discharge performance of lithium thionyl chloride primary batteries is an urgent technical problem to be solved. Summary of the Invention

[0006] To address the shortcomings of existing technologies, the present invention aims to provide a lithium thionyl chloride primary battery and its preparation method. The present invention involves depositing a nano-metal coating on the surface of the lithium metal anode and / or introducing a phthalocyanine metal complex into the thionyl chloride electrolyte. The nano-metal coating not only protects the lithium metal anode from corrosion by thionyl chloride and prevents self-discharge during storage or intermittent discharge periods, but also possesses lithium-philic properties, promoting lithium-ion migration to the positive electrode. The phthalocyanine metal complex has a unique molecular structure and electron cloud distribution, which optimizes the reaction process on the electrode surface, making the reduction reaction of thionyl chloride more efficient, reducing electrode polarization, thereby increasing the battery's discharge voltage and enabling the battery to output a more stable and higher voltage. Simultaneously, it reduces the electrolyte resistance and increases the ion migration rate, thus improving the high-current discharge performance of the lithium thionyl chloride primary battery.

[0007] To achieve this objective, the present invention adopts the following technical solution:

[0008] In a first aspect, the present invention provides a lithium thionyl chloride primary battery, the lithium thionyl chloride primary battery comprising a lithium metal negative electrode, a separator, a positive electrode and a thionyl chloride electrolyte.

[0009] The lithium metal anode has a nano-metal coating on its surface and / or the thionyl chloride electrolyte contains a phthalocyanine metal complex.

[0010] This invention involves depositing a nano-metal coating on the surface of the lithium metal anode and / or introducing a phthalocyanine metal complex into the thionyl chloride electrolyte. The nano-metal coating not only protects the lithium metal anode from corrosion by thionyl chloride and prevents self-discharge during storage or intermittent discharge periods, but also possesses lithium-affinity properties, exhibiting a strong affinity for lithium ions. The phthalocyanine metal complex, with its unique molecular structure and electron cloud distribution, optimizes the reaction process on the electrode surface, making the reduction reaction of thionyl chloride more efficient, reducing electrode polarization, and thus increasing the battery's discharge voltage. This results in a more stable and higher voltage output, while simultaneously reducing electrolyte resistance and increasing ion migration rate, thereby improving the high-current discharge performance of the lithium thionyl chloride primary battery. Therefore, by depositing a nano-metal coating on the surface of the lithium metal anode and / or introducing a phthalocyanine metal complex into the thionyl chloride electrolyte, the lithium thionyl chloride primary battery can respond quickly when discharge is needed and does not experience capacity loss when discharge is not required, while also improving the overall discharge capacity of the battery. Furthermore, in lithium thionyl chloride batteries that have been stored at high temperatures and then discharged, the lithium metal anode exhibits no self-discharge, demonstrating excellent stability. The voltage hysteresis problem present in lithium thionyl chloride batteries has also been improved, achieving full-capacity discharge.

[0011] In this invention, phthalocyanine metal complexes are a class of compounds formed by the combination of phthalocyanine ligands and metal ions through coordination bonds. They can promote the discharge reaction of lithium thionyl chloride primary batteries, reduce discharge impedance, and increase electrode potential.

[0012] Preferably, the material of the nano-metal coating includes any one or a combination of at least two of gold nanoparticles, silver nanoparticles, platinum nanoparticles, or tin nanoparticles.

[0013] Preferably, in the nano-metal coating, the particle size D50 of the nano-metal particles is 20-70nm, for example, it can be 20nm, 30nm, 40nm, 50nm, 60nm or 70nm, etc.

[0014] In this invention, nano-metal particles of suitable size can better protect the lithium metal anode from corrosion by thionyl chloride, prevent self-discharge of the battery during storage or idle periods of intermittent discharge, and have lithium-affinity properties, which can generate a strong affinity for lithium ions.

[0015] Preferably, the thickness of the nano-metal coating is ≤2μm, for example, it can be 2μm, 1.5μm, 1μm, 0.5μm, 0.1μm, 50nm or 10nm, etc., and preferably 0.5-1μm.

[0016] In this invention, a nano-metal coating of suitable thickness not only fully realizes its protective and lithium migration-promoting functions, but also does not affect the overall thickness of the lithium metal anode during battery assembly, while simultaneously reducing the additional cost of the coating material. It should be noted that even with a nano-metal coating thickness as low as 50-100 nm, the corresponding effects can be achieved.

[0017] Preferably, the phthalocyanine metal complex includes any one or a combination of at least two of iron phthalocyanine, copper phthalocyanine, cobalt phthalocyanine, or nickel phthalocyanine, and is preferably cobalt phthalocyanine and / or nickel phthalocyanine.

[0018] In this invention, cobalt phthalocyanine and nickel phthalocyanine can better promote the discharge reaction of lithium thionyl chloride primary batteries, reduce discharge impedance, and increase electrode potential.

[0019] Preferably, the concentration of the phthalocyanine metal complex in the thionyl chloride electrolyte is 0.5-4 mg / mL, for example, it can be 0.5 mg / mL, 1 mg / mL, 1.5 mg / mL, 2 mg / mL, 2.5 mg / mL, 3 mg / mL, 3.5 mg / mL or 4 mg / mL, etc.

[0020] In this invention, the appropriate concentration of phthalocyanine metal complex in thionyl chloride electrolyte not only improves the battery discharge performance, but also, in the process of high-temperature aging, works synergistically with the nano-metal coating to enhance the battery discharge capacity.

[0021] Preferably, when the phthalocyanine metal complex is nickel phthalocyanine, the concentration of the phthalocyanine metal complex is 0.5-2 mg / mL, for example, it can be 0.5 mg / mL, 1 mg / mL, 1.5 mg / mL or 2 mg / mL, etc.

[0022] Preferably, the thionyl chloride electrolyte includes a lithium salt, the concentration of which is 0.7-1.4 mol / L, for example, 0.7 mol / L, 0.9 mol / L, 1.1 mol / L, 1.2 mol / L, 1.3 mol / L or 1.4 mol / L.

[0023] Preferably, the lithium salt includes any one or a combination of at least two of LiAlCl4, LiBF4, LiPF6, or LiClO4.

[0024] Preferably, the positive electrode is a porous carbon positive electrode.

[0025] It should be noted that the present invention does not limit the material of the diaphragm; for example, it can be a glass fiber diaphragm.

[0026] In a second aspect, the present invention provides a method for preparing a lithium thionyl chloride primary battery as described in the first aspect, the method comprising the following steps:

[0027] The lithium metal anode, separator, and cathode are assembled, and then thionyl chloride electrolyte is injected to obtain the lithium thionyl chloride primary battery.

[0028] Prior to assembly, a dispersion containing nano-metal particles is coated onto the surface of the lithium metal anode, and after drying, a nano-metal coating is formed; and / or,

[0029] Phthalocyanine metal complexes are added to the thionyl chloride electrolyte.

[0030] Preferably, the solvent of the dispersion includes any one or a combination of at least two of dimethylacetamide, dimethylformamide, N-methylpyrrolidone, or dimethyl sulfoxide.

[0031] Preferably, the coating method includes any one or a combination of at least two of the following: wire rod coating, drop coating, spray coating, dip coating, blade coating, or roller coating.

[0032] The numerical range described in this invention includes not only the point values ​​listed above, but also any point values ​​within the numerical ranges not listed above. Due to space limitations and for the sake of brevity, this invention will not exhaustively list all the specific point values ​​included in the range.

[0033] Compared with the prior art, the present invention has the following beneficial effects:

[0034] This invention involves depositing a nano-metal coating on the surface of the lithium metal anode and / or introducing a phthalocyanine metal complex into the thionyl chloride electrolyte. The nano-metal coating not only protects the lithium metal anode from corrosion by thionyl chloride and prevents self-discharge during storage or intermittent discharge periods, but also possesses lithium-philic properties, promoting lithium-ion migration to the positive electrode. The phthalocyanine metal complex, with its unique molecular structure and electron cloud distribution, optimizes the reaction process on the electrode surface, making the reduction reaction of thionyl chloride more efficient, reducing electrode polarization, and thus increasing the battery's discharge voltage. This results in a more stable and higher voltage output, while simultaneously reducing electrolyte resistance and increasing ion migration rate, thereby improving the high-current discharge performance of the lithium thionyl chloride primary battery. Therefore, by depositing a nano-metal coating on the surface of the lithium metal anode and / or introducing a phthalocyanine metal complex into the thionyl chloride electrolyte, the lithium thionyl chloride primary battery can respond quickly when discharge is needed and does not experience capacity loss when discharge is not required, while also improving the overall discharge capacity of the battery. Furthermore, in lithium thionyl chloride batteries that have been stored at high temperatures and then discharged, the lithium metal anode exhibits no self-discharge, demonstrating excellent stability. The voltage hysteresis problem present in lithium thionyl chloride batteries has also been improved, achieving full-capacity discharge. Attached Figure Description

[0035] Figure 1 This is a physical image of the lithium metal anode provided in Embodiment 1 of the present invention.

[0036] Figure 2 This is a surface SEM image of the lithium metal anode provided in Embodiment 1 of the present invention.

[0037] Figure 3 This is a cross-sectional SEM image of the lithium metal anode provided in Embodiment 1 of the present invention.

[0038] Figure 4 This is a physical image of the lithium metal anode provided in Embodiment 4 of the present invention.

[0039] Figure 5 This is a surface SEM image of the lithium metal anode provided in Embodiment 4 of the present invention.

[0040] Figure 6 This is a cross-sectional SEM image of the lithium metal anode provided in Embodiment 4 of the present invention.

[0041] Figure 7 The discharge curve of the lithium thionyl chloride primary battery provided in Example 1 of the present invention when it is laid flat under a constant current of 2mA.

[0042] Figure 8 The discharge curve of the lithium thionyl chloride primary battery provided in Example 1 of the present invention when it is placed vertically under a constant current of 2mA.

[0043] Figure 9 The discharge curve of the lithium thionyl chloride primary battery provided in Comparative Example 1 of the present invention is shown when it is laid flat under a constant current of 2mA.

[0044] Figure 10 The discharge curve of the lithium thionyl chloride primary battery provided in Comparative Example 1 of the present invention is shown when it is placed vertically under a constant current of 2mA.

[0045] Figure 11 for Figures 7 to 10 The discharge capacity statistics table.

[0046] Figure 12 The discharge curve of the lithium thionyl chloride primary battery provided in Example 1 of the present invention when it is laid flat under a constant current of 10mA.

[0047] Figure 13 The discharge curve of the lithium thionyl chloride primary battery provided in Comparative Example 1 of the present invention is shown when it is laid flat under a constant current of 10mA.

[0048] Figure 14 for Figure 12 and Figure 13 The discharge capacity statistics table.

[0049] Figure 15 The discharge curve of the lithium thionyl chloride primary battery provided in Example 1 of the present invention is obtained by aging discharge at 10mA and 60°C.

[0050] Figure 16 The discharge curve of the lithium thionyl chloride primary battery provided in Comparative Example 1 of this invention is obtained by aging discharge at 10mA and 60°C.

[0051] Figure 17 for Figure 15 and Figure 16 The discharge capacity statistics table.

[0052] Figure 18 The discharge curve of the lithium thionyl chloride primary battery provided in Example 1 of this invention under aging discharge at 2mA and 60°C.

[0053] Figure 19The discharge curve of the lithium thionyl chloride primary battery provided in Comparative Example 1 of this invention is obtained by aging discharge at 2mA and 60°C.

[0054] Figure 20 for Figure 18 and Figure 19 The discharge capacity statistics table. Detailed Implementation

[0055] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention in any way.

[0056] Example 1

[0057] This embodiment provides a lithium thionyl chloride primary battery, which includes a lithium metal negative electrode, a separator, a positive electrode, and a thionyl chloride electrolyte; the surface of the lithium metal negative electrode is provided with a nano-metal coating.

[0058] The nano-metal coating is made of silver nanoparticles with a particle size D50 of 50 nm and a thickness of 800 nm; the separator is a glass fiber separator; the positive electrode is a porous carbon positive electrode; the thionyl chloride electrolyte includes lithium salt and solvent, the lithium salt is LiAlCl4 with a concentration of 1 mol / L, and the solvent is thionyl chloride.

[0059] This embodiment also provides a method for preparing the above-mentioned lithium thionyl chloride primary battery, the method comprising the following steps:

[0060] (1) A dispersion containing silver nanoparticles is coated onto the surface of a lithium metal anode by spraying and then dried to form a nano-metal coating; wherein the solvent of the dispersion is dimethylacetamide with a concentration of 60 mg / mL.

[0061] (2) Assemble the lithium metal anode with the nano-metal coating, the glass fiber membrane and the porous carbon cathode, and then inject the thionyl chloride electrolyte (where the concentration of LiAlCl4 is 1 mol / L) to obtain the lithium thionyl chloride primary battery.

[0062] Figure 1 and Figure 2 The physical image and surface SEM image of the lithium metal anode provided in this embodiment are shown respectively. As can be seen from the images, the surface of the lithium metal anode is coated with silver nanoparticles, and the particle size on the surface is uniform and the density is excellent.

[0063] Figure 3 The cross-sectional SEM image of the lithium metal anode provided in this embodiment is shown. As can be seen from the image, the thickness of the nano-metal coating is 800 nm, and the particle size is uniform in the longitudinal direction, with excellent density.

[0064] Example 2

[0065] This embodiment provides a lithium thionyl chloride primary battery, which includes a lithium metal anode with a nano-metal coating, a separator, a positive electrode, and a thionyl chloride electrolyte.

[0066] The nano-metal coating is made of gold nanoparticles with a particle size D50 of 20 nm and a thickness of 0.5 μm; the separator is a glass fiber separator; the positive electrode is a porous carbon positive electrode; the thionyl chloride electrolyte includes lithium salt and solvent, the lithium salt is LiAlCl4 with a concentration of 0.7 mol / L and the solvent is thionyl chloride.

[0067] This embodiment also provides a method for preparing the above-mentioned lithium thionyl chloride primary battery, the method comprising the following steps:

[0068] (1) A dispersion containing gold nanoparticles was coated onto the surface of a lithium metal anode by a scraping method and dried to form a nano-metal coating; wherein the solvent of the dispersion was dimethylacetamide with a concentration of 60 mg / mL.

[0069] (2) Assemble the lithium metal anode with the nano-metal coating, the glass fiber membrane and the porous carbon cathode, and then inject the thionyl chloride electrolyte (where the concentration of LiAlCl4 is 0.7 mol / L) to obtain the lithium thionyl chloride primary battery.

[0070] Example 3

[0071] This embodiment provides a lithium thionyl chloride primary battery, which includes a lithium metal anode with a nano-metal coating, a separator, a positive electrode, and a thionyl chloride electrolyte.

[0072] The nano-metal coating is made of platinum nanoparticles with a particle size D50 of 70 nm and a thickness of 1 μm; the separator is made of glass fiber; the positive electrode is a porous carbon positive electrode; the thionyl chloride electrolyte includes lithium salt and solvent, the lithium salt is LiAlCl4 with a concentration of 1.4 mol / L and the solvent is thionyl chloride.

[0073] This embodiment also provides a method for preparing the above-mentioned lithium thionyl chloride primary battery, the method comprising the following steps:

[0074] (1) A dispersion containing platinum nanoparticles was coated onto the surface of a lithium metal anode using a drop-coating method, and dried to form a nano-metal coating; wherein the solvent of the dispersion was dimethylacetamide with a concentration of 60 mg / mL.

[0075] (2) Assemble the lithium metal anode with the nano-metal coating, the glass fiber membrane and the porous carbon cathode, and then inject the thionyl chloride electrolyte (where the concentration of LiAlCl4 is 1.4 mol / L) to obtain the lithium thionyl chloride primary battery.

[0076] Example 4

[0077] The difference between this embodiment and embodiment 1 is that the coating method in step (1) is wire bar coating.

[0078] The remaining preparation methods and parameters are consistent with those in Example 1.

[0079] Figure 4 and Figure 5 The image shows a physical picture and a surface SEM image of the lithium metal anode provided in this embodiment. As can be seen from the image, silver nanoparticles are uniformly distributed on the surface of the lithium metal anode.

[0080] Figure 6 A cross-sectional SEM image of the lithium metal anode provided in this embodiment is shown. As can be seen from the image, the particle size D50 of the silver nanoparticles is 50 nm.

[0081] Example 5

[0082] This embodiment provides a lithium thionyl chloride primary battery, which includes a lithium metal negative electrode, a separator, a positive electrode, and a thionyl chloride electrolyte.

[0083] The separator is a glass fiber separator; the positive electrode is a porous carbon positive electrode; the thionyl chloride electrolyte includes lithium salt, phthalocyanine metal complex and solvent, the lithium salt is LiAlCl4 with a concentration of 1 mol / L, the solvent is thionyl chloride, the phthalocyanine metal complex is phthalocyanine iron with a concentration of 0.5 mg / mL.

[0084] This embodiment also provides a method for preparing the above-mentioned lithium thionyl chloride primary battery, the method comprising the following steps:

[0085] A thionyl chloride electrolyte is provided, wherein the thionyl chloride electrolyte comprises LiAlCl4, iron phthalocyanine and thionyl chloride.

[0086] The lithium metal anode, glass fiber membrane, and porous carbon cathode are assembled, and then injected with thionyl chloride electrolyte (where the concentration of LiAlCl4 is 1 mol / L) to obtain the lithium thionyl chloride primary battery.

[0087] Example 6

[0088] The difference between this embodiment and Embodiment 5 is that the phthalocyanine metal complex is copper phthalocyanine.

[0089] The remaining preparation methods and parameters are consistent with those in Example 5.

[0090] Example 7

[0091] The difference between this embodiment and Embodiment 5 is that the phthalocyanine metal complex is cobalt phthalocyanine.

[0092] The remaining preparation methods and parameters are consistent with those in Example 5.

[0093] Example 8

[0094] The difference between this embodiment and Embodiment 5 is that the phthalocyanine metal complex is nickel phthalocyanine.

[0095] The remaining preparation methods and parameters are consistent with those in Example 5.

[0096] Example 9

[0097] The difference between this embodiment and Embodiment 7 is that the concentration of cobalt phthalocyanine is 1 mg / mL.

[0098] The remaining preparation methods and parameters are consistent with those in Example 7.

[0099] Example 10

[0100] The difference between this embodiment and Embodiment 7 is that the concentration of cobalt phthalocyanine is 2 mg / mL.

[0101] The remaining preparation methods and parameters are consistent with those in Example 7.

[0102] Example 11

[0103] The difference between this embodiment and Embodiment 7 is that the concentration of cobalt phthalocyanine is 4 mg / mL.

[0104] The remaining preparation methods and parameters are consistent with those in Example 7.

[0105] Example 12

[0106] The difference between this embodiment and Embodiment 8 is that the concentration of nickel phthalocyanine is 1 mg / mL.

[0107] The remaining preparation methods and parameters are consistent with those in Example 8.

[0108] Example 13

[0109] The difference between this embodiment and Embodiment 8 is that the concentration of nickel phthalocyanine is 2 mg / mL.

[0110] The remaining preparation methods and parameters are consistent with those in Example 8.

[0111] Example 14

[0112] The difference between this embodiment and embodiment 1 is that the thionyl chloride electrolyte in step (2) contains cobalt phthalocyanine, and the concentration of cobalt phthalocyanine is 0.5 mg / mL.

[0113] The remaining preparation methods and parameters are consistent with those in Example 1.

[0114] Example 15

[0115] The difference between this embodiment and embodiment 1 is that the thionyl chloride electrolyte in step (2) contains nickel phthalocyanine, and the concentration of nickel phthalocyanine is 2 mg / mL.

[0116] The remaining preparation methods and parameters are consistent with those in Example 1.

[0117] Example 16

[0118] The difference between this embodiment and embodiment 1 is that the thionyl chloride electrolyte in step (2) contains nickel phthalocyanine, and the concentration of nickel phthalocyanine is 2 mg / mL.

[0119] The remaining preparation methods and parameters are consistent with those in Example 1.

[0120] Example 17

[0121] The difference between this embodiment and Embodiment 1 is that the silver nanoparticles are replaced with micron-sized silver particles with a particle size D50 of 2 μm.

[0122] The remaining preparation methods and parameters are consistent with those in Example 1.

[0123] Comparative Example 1

[0124] The difference between this comparative example and Example 1 is that the surface of the lithium metal anode is not coated with a nano-metal coating, i.e., step (1) is not performed.

[0125] The remaining preparation methods and parameters are consistent with those in Example 1.

[0126] Comparative Example 2

[0127] The difference between this comparative example and Example 7 is that the thionyl chloride electrolyte does not contain nickel phthalocyanine.

[0128] The remaining preparation methods and parameters are consistent with those in Example 7.

[0129] Performance testing

[0130] Several lithium thionyl chloride primary batteries provided in Example 1 were subjected to discharge tests at a constant current of 2mA. The batteries were placed horizontally and vertically, respectively. The test results are as follows: Figure 7 and Figure 8As shown; several lithium thionyl chloride primary batteries provided in Comparative Example 1 were subjected to discharge tests at a constant current of 2mA. The batteries were placed horizontally and vertically, respectively. The test results are as follows. Figure 9 and Figure 10 As shown; the discharge capacity of the battery after the above discharge test was statistically analyzed, and the results are as follows. Figure 11 The discharge capacity statistics are shown in the figure. The results indicate that the nano-metal coating can improve the discharge capacity consistency of lithium thionyl chloride primary batteries under all conditions.

[0131] Several lithium thionyl chloride primary batteries provided in Example 1 were subjected to discharge tests at a constant current of 10mA. The batteries were placed horizontally, and the test results are as follows. Figure 12 As shown; several lithium thionyl chloride primary batteries provided in Comparative Example 1 were discharged under a constant current of 2mA. The batteries were placed horizontally, and the test results are as follows. Figure 13 As shown; the discharge capacity of the battery after the above discharge test was statistically analyzed, and the results are as follows. Figure 14 The discharge capacity statistics are shown in the figure. The results indicate that under high current conditions, the nano-metal coating has no significant effect on improving the discharge performance of the battery.

[0132] Several lithium thionyl chloride primary batteries provided in Example 1 and Comparative Example 1 were subjected to aging discharge tests in a flat-laying state, including: 1) a constant current of 10mA, an aging temperature of 60°C, and an aging time of 20 days. The test results are as follows. Figure 15 and Figure 16 As shown, the discharge capacity after the discharge test was completed was statistically analyzed, and the results are as follows. Figure 17 As shown in the figure. The results show that the nano-metal coating on lithium metal can improve the discharge capacity of aged lithium thionyl chloride primary batteries under a discharge current of 10mA and in a flat state, and also improve the consistency of battery performance; 2) The constant current of the aging discharge test was 2mA, the aging temperature was 60℃, and the aging time was 20 days. The test results are shown in the figure. Figure 18 and Figure 19 As shown, the discharge capacity after the discharge test was completed was statistically analyzed, and the results are as follows. Figure 20 As shown in the figure. The results indicate that applying a nano-metal coating to lithium metal can improve the discharge capacity of aged lithium thionyl chloride primary batteries at a discharge current of 2 mA in a flat position, and also improve the consistency of battery performance.

[0133] Under room temperature of 25°C, the discharge capacity of several lithium thionyl chloride primary batteries provided in Examples 5, 6, 7, 8 and Comparative Example 2 was tested with a DC current of 10mA, and the average value was taken. The test results are shown in Table 1.

[0134] Table 1

[0135]

[0136]

[0137] As shown in Table 1, the introduction of phthalocyanine metal complexes helps to improve the discharge performance of the battery. Among them, the use of cobalt phthalocyanine or nickel phthalocyanine as additives to be introduced into the thionyl chloride electrolyte has the best effect on improving the discharge performance of the battery.

[0138] Under a constant current of 2mA, several lithium thionyl chloride primary batteries provided in Examples 7, 9, 10, 11 and Comparative Example 2 were subjected to aging discharge tests, and the average value was taken. The test environment temperature was 60°C and the test time was 20 days.

[0139] The test results are shown in Table 2.

[0140] Table 2

[0141]

[0142] As shown in Table 2, when cobalt phthalocyanine is introduced into the thionyl chloride electrolyte as an additive, its concentration is between 1-4 mg / mL. After aging at 60°C for 20 days, the performance of the battery deteriorates, and the higher the concentration, the worse the performance. However, when the concentration of cobalt phthalocyanine in the thionyl chloride electrolyte is 0.5 mg / mL, the thermal aging performance of the battery is stable.

[0143] Under a constant current of 10mA, several lithium thionyl chloride primary batteries provided in Examples 7, 9, 10, 11 and Comparative Example 2 were subjected to aging discharge tests, and the average value was taken. The test environment temperature was 60℃ and the test time was 20 days.

[0144] The test results are shown in Table 3.

[0145] Table 3

[0146]

[0147] As shown in Table 3, under high current conditions, introducing only nickel phthalocyanine into the thionyl chloride electrolyte has little effect on the thermal aging performance of the battery.

[0148] Under a constant current of 2mA, several lithium thionyl chloride primary batteries provided in Examples 8, 12, 13 and Comparative Example 2 were subjected to aging discharge tests, and the average value was taken. The test environment temperature was 60°C and the test time was 20 days.

[0149] The test results are shown in Table 4.

[0150] Table 4

[0151]

[0152] As shown in Table 4, the use of nickel phthalocyanine as an additive in the thionyl chloride electrolyte does not have an adverse effect on the thermal aging performance of the battery, even when the concentration of nickel phthalocyanine is increased to 2 mg / mL.

[0153] Under a constant current of 10mA, several lithium thionyl chloride primary batteries provided in Examples 8, 12, 13 and Comparative Example 2 were subjected to aging discharge tests, and the average value was taken. The test environment temperature was 60℃ and the test time was 20 days.

[0154] The test results are shown in Table 5.

[0155] Table 5

[0156]

[0157] As shown in Table 5, under high current conditions, the use of nickel phthalocyanine as an additive in the thionyl chloride electrolyte, even at low concentrations, does not adversely affect the thermal aging performance of the battery.

[0158] Under a constant current of 2mA, several lithium thionyl chloride primary batteries provided in Examples 1, 7, 13, 14, 15 and Comparative Example 1 were subjected to aging discharge tests, and the average value was taken. The test environment temperature was 70°C and the test time was 30 days.

[0159] The test results are shown in Table 6.

[0160] Table 6

[0161]

[0162] As shown in Table 6, when nickel phthalocyanine is introduced as an additive into the thionyl chloride electrolyte, and a silver nanoparticle coating is applied to the surface of the lithium metal anode, the two work synergistically to significantly improve the battery's discharge capacity and exhibit excellent thermal aging stability.

[0163] Furthermore, a comparison between Example 1 and Example 17 shows that if micron-sized silver particles are coated onto the surface of the lithium metal anode to form a micron-sized metal coating, the thinnest possible coating thickness will be at least within the range of micron-sized silver D50 or even thicker (the thickness will be above 2 microns), and maintaining a consistent thickness will be more difficult. Moreover, an excessively thick coating on the lithium sheet may affect battery assembly. Additionally, using micron-sized silver particles means directly introducing more silver into the battery lithium sheet, which increases additional costs and is not conducive to cost reduction and efficiency improvement.

[0164] It should be noted that the present invention is illustrated through the above embodiments, but the present invention is not limited to the above process steps, that is, it does not mean that the present invention must rely on the above process steps to be implemented. Those skilled in the art should understand that any improvements to the present invention, equivalent substitutions of the raw materials used in the present invention, additions of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A lithium thionyl chloride primary battery, characterized in that, The lithium thionyl chloride primary battery includes a lithium metal negative electrode, a separator, a positive electrode, and a thionyl chloride electrolyte; The lithium metal anode is provided with a nano-metal coating on its surface and the thionyl chloride electrolyte includes a phthalocyanine metal complex. The thickness of the nano-metal coating is 0.8-2 μm.

2. The lithium thionyl chloride primary battery according to claim 1, characterized in that, The material of the nano-metal coating includes any one or a combination of at least two of gold nanoparticles, silver nanoparticles, platinum nanoparticles, or tin nanoparticles.

3. The lithium thionyl chloride primary battery according to claim 1, characterized in that, In the nano-metal coating, the particle size D50 of the nano-metal particles is 20-70 nm.

4. The lithium thionyl chloride primary battery according to claim 1, characterized in that, The phthalocyanine metal complex includes any one or a combination of at least two of iron phthalocyanine, copper phthalocyanine, cobalt phthalocyanine, or nickel phthalocyanine.

5. The lithium thionyl chloride primary battery according to claim 4, characterized in that, The phthalocyanine metal complex is cobalt phthalocyanine and / or nickel phthalocyanine.

6. The lithium thionyl chloride primary battery according to claim 1, characterized in that, The concentration of the phthalocyanine metal complex in the thionyl chloride electrolyte is 0.5-4 mg / mL.

7. The lithium thionyl chloride primary battery according to claim 1, characterized in that, The thionyl chloride electrolyte includes a lithium salt, the concentration of which is 0.7-1.4 mol / L; The lithium salt includes any one or a combination of at least two of LiAlCl4, LiBF4, LiPF6, or LiClO4; The cathode is a porous carbon cathode.

8. A method for preparing a lithium thionyl chloride primary battery as described in any one of claims 1-7, characterized in that, The preparation method includes the following steps: The lithium metal anode, separator and cathode are assembled, and then thionyl chloride electrolyte is injected to obtain the lithium thionyl chloride primary battery; Prior to assembly, a dispersion containing nano-metal particles is applied to the surface of the lithium metal anode, and after drying, a nano-metal coating is formed; a phthalocyanine metal complex is added to the thionyl chloride electrolyte.

9. The method for preparing a lithium thionyl chloride primary battery according to claim 8, characterized in that, The solvent of the dispersion includes any one or a combination of at least two of dimethylacetamide, dimethylformamide, N-methylpyrrolidone, or dimethyl sulfoxide.

10. The method for preparing a lithium thionyl chloride primary battery according to claim 9, characterized in that, The coating method includes any one or a combination of at least two of the following: wire rod coating, drop coating, spray coating, dip coating, scraping coating, or roller coating.

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