Lithium thionyl chloride primary battery and preparation method thereof

Abstract

The invention provides a lithium thionyl chloride primary battery and a preparation method thereof. The lithium thionyl chloride primary battery comprises a lithium metal negative electrode, a diaphragm, a positive electrode and thionyl chloride electrolyte; wherein the surface of the lithium metal negative electrode is provided with a nano metal coating and / or the thionyl chloride electrolyte comprises a phthalocyanine metal complex. According to the invention, the nano-metal coating can protect the lithium metal negative electrode from being corroded by thionyl chloride, so that the battery is prevented from self-discharge during a storage period or an idle period of intermittent discharge, and lithium ions can be promoted to migrate to the positive electrode; the phthalocyanine metal complex can preferably enable the reduction reaction of thionyl chloride to be carried out more efficiently, the discharge voltage of the battery is improved, meanwhile, the resistance of the electrolyte can be reduced, and the high-current discharge performance of the lithium thionyl chloride primary battery is improved. Therefore, the lithium thionyl chloride primary battery can quickly respond when discharging is needed, capacity loss is avoided when discharging is not needed, and the overall discharging capacity of the battery can be improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of primary batteries, and particularly relates to a lithium thionyl chloride primary battery and a preparation method thereof. Background Art

[0002] A lithium thionyl chloride primary battery is a non-rechargeable battery that only involves a discharge reaction. The overall discharge electrochemical reaction is as follows: 2SOCl2 + 4Li → 4LiCL + SO2 + S. Among them, SOCl2 is thionyl chloride, and this liquid cathode component also serves as the electrolyte (cathode electrolyte), which is accommodated in a porous carbon electrode or a cathode current collector; Li is the lithium anode, which is also the negative terminal of the battery. The overall discharge electrochemical reaction consists of two half-reaction equations, and these two half-reactions occur at the lithium anode (Li → Li + + e) and the cathode (2SOCl2 + 4Li + + 4e → 4LiCl + SO2 + S) respectively. Therefore, during the discharge process, the lithium anode discharges to generate lithium ions and electrons. The electrons flow through the external circuit to the positive electrode of the battery, while the lithium ions move inside the battery. At the cathode, thionyl chloride undergoes a reduction reaction after receiving electrons from the external circuit and lithium ions from the electrolyte.

[0003] However, in addition to occurring at the cathode as required for discharge, the discharge reaction also occurs on the surface of lithium due to the direct contact of the lithium anode with the thionyl chloride cathode electrolyte in the battery. This reaction will cause corrosion and self-discharge due to the continuous consumption of the cathode electrolyte and lithium metal. Under normal circumstances, when this reaction occurs on the surface of lithium metal, a layer of lithium chloride will be deposited and formed. This lithium chloride layer is derived from the initial corrosion reaction and has a passivation effect on lithium metal, which can inhibit further rapid corrosion. Therefore, it is called a passivation layer. However, the passivation layer naturally formed on the surface of lithium metal has defects: on the one hand, it increases the impedance of the subsequent discharge of the battery; on the other hand, this layer cannot provide complete anti-corrosion protection for lithium metal. Therefore, during long-term storage or operation, the self-discharge phenomenon continues to occur, ultimately resulting in a significant decrease in the discharge capacity of the battery.

[0004] In addition, when the lithium thionyl chloride primary battery discharges at a high discharge current, due to the low efficiency of the electrochemical process of thionyl chloride reduction, the discharge limitation often appears on the cathode side, resulting in the influence on the discharge performance of the battery.

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

[0006] In view of the deficiencies of the prior art, the purpose of the present invention is to provide a primary lithium thionyl chloride battery and a preparation method thereof. In the present invention, a nano-metal coating is provided on the surface of the lithium metal anode and / or a metal phthalocyanine complex is introduced into the thionyl chloride electrolyte. Among them, the nano-metal coating can not only protect the lithium metal anode from the corrosion of thionyl chloride, prevent self-discharge of the battery during storage or the idle period of intermittent discharge, but also has a lithium-philic property, which can promote the migration of lithium ions to the cathode; the metal phthalocyanine complex has a unique molecular structure and electron cloud distribution, which can optimize the reaction process on the electrode surface, make the reduction reaction of thionyl chloride proceed more efficiently, reduce electrode polarization, thereby increasing the discharge voltage of the battery, enabling the battery to output a more stable and higher voltage, and at the same time can reduce the resistance of the electrolyte and improve the ion migration rate, thus being beneficial to improving the high-current discharge performance of the primary lithium thionyl chloride battery.

[0007] To achieve the object of the present invention, the following technical solutions are adopted:

[0008] In the first aspect, the present invention provides a primary lithium thionyl chloride battery, which includes a lithium metal anode, a separator, a cathode, and a thionyl chloride electrolyte.

[0009] Among them, a nano-metal coating is provided on the surface of the lithium metal anode and / or the thionyl chloride electrolyte includes a metal phthalocyanine complex.

[0010] In the present invention, a nano-metal coating is provided on the surface of the lithium metal anode and / or a metal phthalocyanine complex is introduced into the thionyl chloride electrolyte. Among them, the nano-metal coating can not only protect the lithium metal anode from the corrosion of thionyl chloride, prevent self-discharge of the battery during storage or the idle period of intermittent discharge, but also has a lithium-philic property, which can have a strong affinity for lithium ions; the metal phthalocyanine complex has a unique molecular structure and electron cloud distribution, which can optimize the reaction process on the electrode surface, make the reduction reaction of thionyl chloride proceed more efficiently, reduce electrode polarization, thereby increasing the discharge voltage of the battery, enabling the battery to output a more stable and higher voltage, and at the same time can reduce the resistance of the electrolyte and improve the ion migration rate, thus being beneficial to improving the high-current discharge performance of the primary lithium thionyl chloride battery. Therefore, after a nano-metal coating is provided on the surface of the lithium metal anode and / or a metal phthalocyanine complex is introduced into the thionyl chloride electrolyte, the primary lithium thionyl chloride battery can respond quickly when discharging is required, and there will be no capacity loss when discharging is not required, and the overall discharge capacity of the battery can also be improved. In addition, in a lithium thionyl chloride battery discharged after high-temperature storage, there is no self-discharge phenomenon on the lithium metal anode, showing excellent stability. The voltage hysteresis problem existing in the lithium thionyl chloride battery is also improved, and full-capacity discharge is achieved.

[0011] In the present invention, the phthalocyanine metal complex is a class of compounds formed by the combination of a phthalocyanine ligand and a metal ion through a coordination bond, which can promote the discharge reaction of a primary lithium thionyl chloride battery, reduce the discharge impedance, and increase the potential of the electrode.

[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 - 70 nm, for example, it can be 20 nm, 30 nm, 40 nm, 50 nm, 60 nm, or 70 nm, etc.

[0014] In the present invention, nano-metal particles with an appropriate particle size can better protect the lithium metal anode from the corrosion of thionyl chloride, prevent self-discharge of the battery during storage or the idle period of intermittent discharge, and moreover, they have a lithium-philic property and can generate a strong affinity for lithium ions.

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

[0016] In the present invention, a nano-metal coating with an appropriate thickness can not only fully achieve its own protective effect and promote lithium migration effect, but also will not affect the overall thickness of the lithium metal anode during battery assembly, and at the same time, it can also reduce the additional cost of the coating material. It should be noted that even when the thickness of the nano-metal coating is as low as 50 - 100 nm, the corresponding effect 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 preferably cobalt phthalocyanine and / or nickel phthalocyanine.

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

[0019] Preferably, in the thionyl chloride electrolyte, the concentration of the phthalocyanine metal complex 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 the present invention, a phthalocyanine metal complex at an appropriate concentration can not only improve the battery discharge performance in thionyl chloride electrolyte, but also cooperate with the nano-metal coating during the high-temperature aging process to synergistically improve 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, 2 mg / mL, etc.

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

[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 separator. Exemplarily, for example, it can be a glass fiber separator, etc.

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

[0027] Assemble the lithium metal negative electrode, the separator, and the positive electrode, and then inject the thionyl chloride electrolyte to obtain the lithium thionyl chloride primary battery.

[0028] Wherein, before assembly, the surface of the lithium metal negative electrode is coated with a dispersion liquid containing nano-metal particles, and a nano-metal coating is formed after drying; and / or,

[0029] Add the phthalocyanine metal complex to the thionyl chloride electrolyte.

[0030] Preferably, the solvent of the dispersion liquid 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 wire bar coating method, drop coating method, spraying method, dip coating method, scraping method, or roll coating method.

[0032] The numerical ranges described in the present invention include not only the point values listed above, but also any point values between the above numerical ranges that are not listed. Due to space limitations and for the sake of brevity, the present invention does not exhaustively list the specific point values included in the described ranges.

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

[0034] The present invention provides a nano-metal coating on the surface of the lithium metal anode and / or introduces a metal phthalocyanine complex into the thionyl chloride electrolyte. Among them, the nano-metal coating can not only protect the lithium metal anode from corrosion by thionyl chloride, prevent self-discharge of the battery during storage or the idle period of intermittent discharge, but also has a lithium-philic property, which can promote the migration of lithium ions to the positive electrode; the metal phthalocyanine complex has a unique molecular structure and electron cloud distribution, which can optimize the reaction process on the electrode surface, make the reduction reaction of thionyl chloride proceed more efficiently, reduce electrode polarization, thereby increasing the discharge voltage of the battery, enabling the battery to output a more stable and higher voltage, and at the same time can reduce the resistance of the electrolyte and improve the migration rate of ions, thus facilitating the improvement of the high-current discharge performance of the primary lithium thionyl chloride battery. Therefore, after providing a nano-metal coating on the surface of the lithium metal anode and / or introducing a metal phthalocyanine complex into the thionyl chloride electrolyte, the primary lithium thionyl chloride battery can respond quickly when discharging is required, and there will be no capacity loss when discharging is not required, and the overall discharge capacity of the battery can also be improved. In addition, in the lithium thionyl chloride battery discharged after high-temperature storage, there is no self-discharge phenomenon on the lithium metal anode, showing excellent stability. The voltage hysteresis problem existing in the lithium thionyl chloride battery is also improved, achieving full-capacity discharge. BRIEF DESCRIPTION OF THE DRAWINGS

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

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

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

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

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

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

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

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

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

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

[0045] Figure 11 For Figures 7 to 10 Discharge capacity statistical table.

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

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

[0048] Figure 14 For Figure 12 And Figure 13 Discharge capacity statistical table.

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

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

[0051] Figure 17 For Figure 15 And Figure 16 Discharge capacity statistical table.

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

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

[0054] Figure 20 is Figure 18 and Figure 19 the statistical table of discharge capacity. Specific Embodiments

[0055] The technical solution of the present invention will be further described below through specific embodiments. Those skilled in the art should understand that the embodiments are only for helping to understand the present invention and should not be regarded as specific limitations on the present invention.

[0056] Example 1

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

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

[0059] This example also provides a preparation method for the above primary lithium thionyl chloride battery, and the preparation method includes the following steps:

[0060] (1) Using the spraying method, a dispersion liquid containing silver nanoparticles is coated on the surface of the lithium metal negative electrode, and after drying, a nano-metal coating is formed; among them, the solvent of the dispersion liquid is dimethylacetamide, and the concentration is 60 mg / mL.

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

[0062] Figure 1 and Figure 2 respectively show the physical diagram and the surface SEM diagram of the lithium metal negative electrode provided in this example. It can be seen from the figure that a silver nanoparticle coating is provided on the surface of the lithium metal negative electrode, and the particle size on the surface is uniform and the compactness is excellent.

[0063] Figure 3 shows the cross-sectional SEM diagram of the lithium metal negative electrode provided in this example. It can be seen from the figure that the thickness of the nano-metal coating is 800 nm, and the particle size is uniform and the compactness is excellent longitudinally.

[0064] Example 2

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

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

[0067] This example also provides a preparation method for the above primary lithium thionyl chloride battery, and the preparation method includes the following steps:

[0068] (1) Using the doctor blade coating method, a dispersion liquid containing gold nanoparticles is coated on the surface of the lithium metal negative electrode, and after drying, a nano metal coating is formed; among them, the solvent of the dispersion liquid is dimethylacetamide, and the concentration is 60 mg / mL.

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

[0070] Example 3

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

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

[0073] This example also provides a preparation method for the above primary lithium thionyl chloride battery, and the preparation method includes the following steps:

[0074] (1) Using the drop coating method, a dispersion liquid containing platinum nanoparticles is coated on the surface of the lithium metal negative electrode, and after drying, a nano metal coating is formed; among them, the solvent of the dispersion liquid is dimethylacetamide, and the concentration is 60 mg / mL.

[0075] (2) Assemble the lithium metal negative electrode with the nanometal coating, the glass fiber separator, and the porous carbon positive electrode, and then inject thionyl chloride electrolyte (where the concentration of LiAlCl4 is 1.4 mol / L) to obtain the primary lithium thionyl chloride battery.

[0076] Example 4

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

[0078] The remaining preparation methods and parameters are the same as those in Example 1.

[0079] Figure 4 and Figure 5 Figs. show the physical diagram and the surface SEM diagram of the lithium metal negative electrode provided in this example. It can be seen from the figures that silver nanoparticles are evenly distributed on the surface of the lithium metal negative electrode.

[0080] Figure 6 Figs. show the cross-sectional SEM diagram of the lithium metal negative electrode provided in this example. It can be seen from the figures that the particle size D50 of the silver nanoparticles is 50 nm.

[0081] Example 5

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

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

[0084] This example also provides a preparation method for the above primary lithium thionyl chloride battery, and the preparation method includes the following steps:

[0085] Provide a thionyl chloride electrolyte, and the thionyl chloride electrolyte includes LiAlCl4, phthalocyanine iron, and thionyl chloride.

[0086] Assemble the lithium metal negative electrode, the glass fiber separator, and the porous carbon positive electrode, and then inject thionyl chloride electrolyte (where the concentration of LiAlCl4 is 1 mol / L) to obtain the primary lithium thionyl chloride battery.

[0087] Example 6

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

[0089] The remaining preparation methods and parameters are the same as those in Example 5.

[0090] Example 7

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

[0092] The remaining preparation methods and parameters are the same as those in Example 5.

[0093] Example 8

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

[0095] The remaining preparation methods and parameters are the same as those in Example 5.

[0096] Example 9

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

[0098] The remaining preparation methods and parameters are the same as those in Example 7.

[0099] Example 10

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

[0101] The remaining preparation methods and parameters are the same as those in Example 7.

[0102] Example 11

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

[0104] The remaining preparation methods and parameters are the same as those in Example 7.

[0105] Example 12

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

[0107] The remaining preparation methods and parameters are the same as those in Example 8.

[0108] Example 13

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

[0110] The remaining preparation methods and parameters are the same as those in Example 8.

[0111] Example 14

[0112] The difference between this example and Example 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 the same as those in Example 1.

[0114] Example 15

[0115] The difference between this example and Example 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 the same as those in Example 1.

[0117] Example 16

[0118] The difference between this example and Example 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 the same as those in Example 1.

[0120] Example 17

[0121] The difference between this example and Example 1 is that the silver nanoparticles are replaced with micron-sized silver particles, and their D50 particle size is 2 μm.

[0122] The remaining preparation methods and parameters are the same as those in Example 1.

[0123] Comparative Example 1

[0124] The difference between this comparative example and Example 1 is that a nano-metal coating is not provided on the surface of the lithium metal negative electrode, that is, step (1) is not performed.

[0125] The remaining preparation methods and parameters are the same as 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 the same as those in Example 7.

[0129] Performance Test

[0130] Discharge tests were carried out on several primary lithium thionyl chloride batteries provided in Example 1 under a constant current of 2 mA, and the battery states were horizontal and vertical placements respectively. The test results are as Figure 7 and Figure 8As shown; several lithium thionyl chloride primary batteries provided in Comparative Example 1 were subjected to a discharge test at a constant current of 2 mA, and the battery states were horizontal and vertical placement respectively. The test results are as Figure 9 and Figure 10 shown; the discharge capacities of the batteries after the above discharge tests were statistically analyzed, and a discharge capacity statistical chart as shown in Figure 11 was obtained. The results show that the nano-metal coating can improve the discharge capacity consistency of lithium thionyl chloride primary batteries in each case.

[0131] Several lithium thionyl chloride primary batteries provided in Example 1 were subjected to a discharge test at a constant current of 10 mA, and the battery state was horizontal. The test results are as Figure 12 shown; several lithium thionyl chloride primary batteries provided in Comparative Example 1 were subjected to a discharge test at a constant current of 2 mA, and the battery state was horizontal. The test results are as Figure 13 shown; the discharge capacities of the batteries after the above discharge tests were statistically analyzed, and a discharge capacity statistical chart as shown in Figure 14 was obtained. The results show that in the case of high current, the nano-metal coating has no obvious improvement effect on the discharge performance of the battery.

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

[0133] Under the condition of room temperature of 25 °C, the discharge capacity tests were carried out on several lithium thionyl chloride primary batteries provided in Example 5, Example 6, Example 7, Example 8 and Comparative Example 2 with a direct current of 10 mA, and the average values were taken. The test results are shown in Table 1.

[0134] Table 1

[0135]

[0136]

[0137] As can be seen from Table 1, the introduction of metal phthalocyanine complexes helps to improve the discharge performance of the battery. Among them, using cobalt phthalocyanine or nickel phthalocyanine as an additive and introducing it into the thionyl chloride electrolyte has the best effect on improving the discharge performance of the battery.

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

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

[0140] Table 2

[0141]

[0142] As can be seen from Table 2, when using cobalt phthalocyanine as an additive and introducing it into the thionyl chloride electrolyte, when its concentration is between 1 - 4 mg / mL, after the battery is aged at 60 °C for 20 days, the performance will deteriorate, 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 the condition of a constant current of 10 mA, several primary lithium thionyl chloride batteries provided in Example 7, Example 9, Example 10, Example 11 and Comparative Example 2 were subjected to an aging discharge test, and the average value was taken. The temperature of the test environment was 60 °C and the time was 20 days.

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

[0145] Table 3

[0146]

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

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

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

[0150] Table 4

[0151]

[0152] As can be seen from Table 4, when nickel phthalocyanine is used as an additive and introduced into the thionyl chloride electrolyte, even when the concentration of nickel phthalocyanine is increased to 2 mg / mL, it will not have an adverse effect on the thermal aging performance of the battery.

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

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

[0155] Table 5

[0156]

[0157] As can be seen from Table 5, under high current conditions, when nickel phthalocyanine is used as an additive and introduced into the thionyl chloride electrolyte, nickel phthalocyanine with a lower concentration will not have an adverse effect on the thermal aging performance of the battery.

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

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

[0160] Table 6

[0161]

[0162] As can be seen from Table 6, when nickel phthalocyanine is used as an additive and introduced into the thionyl chloride electrolyte, and at the same time a silver nanoparticle coating is provided on the surface of the lithium metal anode, the two cooperate synergistically, which can significantly improve the discharge capacity of the battery and exhibit excellent thermal aging stability.

[0163] In addition, by comparing Example 1 and Example 17, it can be seen that if micron-sized silver particles are coated on the surface of the lithium metal anode to form a micron metal coating, the thinnest thickness that can be coated will be at least in the range of micron silver D50 or thicker (the thickness will be more than 2 microns), and it will be more difficult to maintain a consistent thickness. Moreover, an overly thick coating on the lithium sheet may affect battery assembly. In addition, using micron-sized silver particles means directly introducing more silver into the battery lithium sheet, which will increase additional costs and is not conducive to cost reduction and efficiency improvement.

[0164] It should be noted that the present invention illustrates the process method of the present invention 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 improvement to the present invention, the equivalent substitution of the raw materials selected for the present invention, the addition of auxiliary components, the selection of specific methods, etc. all fall within the protection scope and the disclosure scope of the present invention.

Claims

1. A primary lithium thionyl chloride battery, characterized in that, The primary lithium thionyl chloride battery includes a lithium metal negative electrode, a separator, a positive electrode, and a thionyl chloride electrolyte; wherein, a nano metal coating is provided on the surface of the lithium metal negative electrode and / or the thionyl chloride electrolyte includes a phthalocyanine metal complex.

2. The primary lithium thionyl chloride 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 primary lithium thionyl chloride battery according to claim 1 or 2, characterized in that, In the nano metal coating, the particle size D50 of the nano metal particles is 20 - 70 nm.

4. The primary lithium thionyl chloride battery according to any one of claims 1 to 3, characterized in that, The thickness of the nano metal coating ≤ 5 μm, preferably 0.5 - 2 μm.

5. The primary lithium thionyl chloride battery according to any one of claims 1-4, 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, preferably cobalt phthalocyanine and / or nickel phthalocyanine.

6. The primary lithium thionyl chloride battery according to any one of claims 1-5, characterized in that, In the thionyl chloride electrolyte, the concentration of the phthalocyanine metal complex is 0.5 - 4 mg / mL.

7. The primary lithium thionyl chloride battery according to any one of claims 1-6, characterized in that, The thionyl chloride electrolyte includes a lithium salt, and the concentration of the lithium salt is 0.7 - 1.4 mol / L; and / or, the lithium salt includes any one or a combination of at least two of LiAlCl4, LiBF4, LiPF6, or LiClO4; and / or, the positive electrode is a porous carbon positive electrode.

8. A method for preparing a primary lithium thionyl chloride battery according to any one of claims 1-7, characterized in that, The preparation method includes the following steps: Assemble the lithium metal negative electrode, the separator, and the positive electrode, and then inject the thionyl chloride electrolyte to obtain the primary lithium thionyl chloride battery; wherein, before assembly, the surface of the lithium metal negative electrode is coated with a dispersion liquid containing nano metal particles, and after drying, a nano metal coating is formed; and / or, Add the phthalocyanine metal complex to the thionyl chloride electrolyte.

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

10. The preparation method of the lithium thionyl chloride primary battery according to claim 8 or 9, characterized in that, The coating method includes any one or a combination of at least two of wire bar coating method, drop coating method, spraying method, dip coating method, knife coating method, or roll coating method.

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