A battery and an interface pretreatment method thereof

Abstract

The application provides a battery and an interface pretreatment method thereof. The positive active material of the battery comprises a primary battery material and a lithium source material; and the interface pretreatment method comprises charging the battery or performing multiple charge-discharge cycles. The application provides a battery and an interface pretreatment method thereof. By performing interface pretreatment on the battery, the quality of the solid-state electrolyte interface film of the battery can be greatly improved, the self-discharge rate of the battery can be significantly reduced, and the voltage hysteresis can be effectively alleviated or eliminated, so that the performance consistency and storage reliability of the battery are improved.

Description

Technical Field

[0001] This application relates to the field of battery technology, and in particular to a battery and a method for interface preprocessing of the battery. Background Technology

[0002] Lithium metal primary batteries offer advantages such as high energy density, long storage life, and stable operating voltage, leading to their widespread application in fields such as IoT sensors, remote monitoring, medical implants, and military equipment. However, lithium metal primary batteries generally suffer from significant self-discharge and voltage hysteresis. The root cause of these issues lies in the porous and unevenly composed solid electrolyte interface film spontaneously formed between the lithium metal anode and the electrolyte. This makes it difficult to effectively prevent continuous side reactions between the electrolyte and lithium, resulting in the continuous consumption of active materials and a sharp voltage drop during the initial discharge phase after long-term storage.

[0003] In the field of rechargeable lithium batteries, a dense and uniform solid electrolyte interface film can be formed on the surface of the negative electrode through the first controlled charge. However, the positive electrode active material of a primary battery can only undergo an irreversible lithium intercalation reaction and cannot be formed through controlled charging. Forcing charging will damage the positive electrode structure and cause safety problems.

[0004] Based on this, this application provides a battery and a battery interface pretreatment method, which can effectively generate a dense and uniform solid electrolyte interface film in a primary battery. Summary of the Invention

[0005] This application provides a battery and a battery interface pretreatment method, which can effectively generate a dense and uniform solid electrolyte interface film in a lithium metal primary battery, thereby significantly suppressing self-discharge and eliminating voltage hysteresis.

[0006] This application provides a battery, comprising: a positive electrode and a negative electrode, wherein the positive electrode comprises a positive electrode current collector and a positive electrode active material coated on the positive electrode current collector, the positive electrode active material comprising a primary battery material and a lithium source material, and the negative electrode comprises a negative electrode current collector and a negative electrode active material coated on the negative electrode current collector.

[0007] In some embodiments of this application, the capacity provided by the primary battery material accounts for more than or equal to 90% of the total capacity of the battery.

[0008] In some embodiments of this application, the primary battery material includes any one of manganese dioxide, vanadium pentoxide, carbon fluoride, iron disulfide, and copper oxide.

[0009] In some embodiments of this application, the lithium source material includes any one of the following: lithium iron phosphate, lithium manganese phosphate, nickel-cobalt-manganese ternary materials, nickel-cobalt-aluminum ternary materials, lithium-rich manganese-based materials, lithium manganese oxide, lithium oxalate, lithium peroxide, lithium nickel oxide, lithium copper oxide, and lithium sulfide.

[0010] In some embodiments of this application, the negative electrode material includes any one of metallic lithium, metallic lithium foil, and lithium alloy.

[0011] Another aspect of this application provides a battery interface pretreatment method, comprising: providing a battery as described above; charging the battery within the capacity range provided by the lithium source material, or performing multiple charge and discharge cycles on the battery.

[0012] In some embodiments of this application, the charging current during interface preprocessing of the battery is DC or DC superimposed with sinusoidal AC.

[0013] In some embodiments of this application, the charging temperature for charging the battery is 20 to 25 degrees Celsius, and the charging rate for charging the battery is 0.1C to 0.3C.

[0014] In some embodiments of this application, at least one of the charging current and discharging current for multiple charge and discharge cycles of the battery is a DC superimposed sinusoidal AC.

[0015] In some embodiments of this application, when the battery undergoes multiple charge and discharge cycles, the charging temperature is 20 to 25 degrees Celsius, the charging rate is 0.1C to 0.3C, and when the charging current is DC superimposed with sinusoidal AC, the charging frequency is 1kHz to 1MHz, and the charging amplitude is 50% of the DC charging rate. Similarly, when the battery undergoes multiple charge and discharge cycles, the discharging temperature is 20 to 25 degrees Celsius, the discharging rate is 0.1C to 0.3C, and when the discharging current is DC superimposed with sinusoidal AC, the discharging frequency is 1kHz to 1MHz, and the discharging amplitude is 50% of the DC discharging rate.

[0016] This application provides a battery and a battery interface pretreatment method, which can effectively generate a dense and uniform solid electrolyte interface film in a lithium metal primary battery, thereby significantly suppressing self-discharge and eliminating voltage hysteresis. Attached Figure Description

[0017] The following accompanying drawings describe in detail the exemplary embodiments disclosed in this application. The same reference numerals denote similar structures in several views of the drawings. Those skilled in the art will understand that these embodiments are non-limiting and exemplary, and the drawings are for illustrative purposes only and are not intended to limit the scope of this application. Other embodiments may similarly fulfill the inventive intent of this application. It should be understood that the drawings are not drawn to scale. Wherein: Figure 1 This is a flowchart of a battery interface preprocessing method described in some embodiments of this application; Figure 2 This is a comparison chart of EIS test results before and after battery interface pretreatment in Embodiment 1 of this application; Figure 3 This is a comparison chart of EIS test results before and after battery interface pretreatment in Embodiment 2 of this application. Detailed Implementation

[0018] The following description provides specific application scenarios and requirements for this application, intended to enable those skilled in the art to make and use the content of this application. Various partial modifications to the embodiments of the application will be apparent to those skilled in the art, and the general principles defined herein can be applied to other embodiments and applications without departing from the spirit and scope of this application. Therefore, this application is not limited to the embodiments shown, but rather to the widest scope consistent with the claims.

[0019] The technical solution of the present invention will be described in detail below with reference to the embodiments and accompanying drawings.

[0020] Lithium metal primary batteries offer advantages such as high specific energy, long storage life, and stable operating voltage. However, the solid electrolyte interface film that spontaneously forms when lithium metal comes into contact with the electrolyte, without the regulation of an external electric field, inherently suffers from a loose structure and uneven composition. This solid electrolyte interface film cannot effectively isolate the continuous side reactions between the electrolyte and lithium metal, leading to irreversible consumption of active lithium and electrolyte. This is the fundamental reason for the increased self-discharge and internal resistance after long-term battery storage. Simultaneously, the continuously thickening and disordered solid electrolyte interface film during storage forces lithium-ion transport to overcome an additional energy barrier during the initial stage of discharge, causing voltage hysteresis and severely affecting the immediate start-up reliability of electrical equipment.

[0021] In the field of rechargeable lithium batteries, a thin, dense, and uniformly composed solid electrolyte interfacial film can be formed on the surface of the negative electrode through controlled charging, i.e., formation processes. However, this film formation mechanism is inherently impossible for primary battery systems. The fundamental obstacle lies in the fact that the irreversible lithium-intercalated cathode material of primary batteries does not contain lithium ions available for extraction in its initial state, and its delithiation reaction is highly irreversible electrochemically. Forcibly applying a charging current not only fails to effectively delithigate lithium but also causes safety issues such as damage to the cathode structure and decomposition of the electrolyte.

[0022] Based on this, this application provides a battery and method that enables a primary battery system to obtain a solid electrolyte interface film with an effect equivalent to that of a rechargeable battery, thereby systematically solving the problems of self-discharge and voltage hysteresis.

[0023] This application provides a battery, comprising: a positive electrode and a negative electrode, wherein the positive electrode comprises a positive electrode current collector and a positive electrode active material coated on the positive electrode current collector, the positive electrode active material comprising a primary battery material and a lithium source material, and the negative electrode comprises a negative electrode current collector and a negative electrode active material coated on the negative electrode current collector.

[0024] In some embodiments of this application, the capacity provided by the primary battery material accounts for more than or equal to 90% of the total capacity of the battery. Because such batteries are designed for "primary energy conversion" and require the use of primary battery materials to provide high specific energy and a stable discharge platform, the proportion of primary battery materials needs to exceed 90%.

[0025] In some embodiments of this application, the primary battery material includes any one of manganese dioxide, vanadium pentoxide, carbon fluoride, iron disulfide, and copper oxide.

[0026] In some embodiments of this application, the lithium source material includes any one of the following: lithium iron phosphate, lithium manganese phosphate, nickel-cobalt-manganese ternary materials, nickel-cobalt-aluminum ternary materials, lithium-rich manganese-based materials, lithium manganese oxide, lithium oxalate, lithium peroxide, lithium nickel oxide, lithium copper oxide, and lithium sulfide.

[0027] In some embodiments of this application, the negative electrode material includes lithium metal, lithium metal foil, or lithium alloy.

[0028] This application provides a battery in which a positive electrode material is a mixture of primary battery materials and lithium source materials in a certain ratio. This provides a certain capacity of charging capability to a primary battery system using irreversible positive electrode active materials.

[0029] This application also provides an interface pretreatment method for the above-mentioned battery, which enables the battery to effectively generate a dense and uniform solid electrolyte interface film.

[0030] Figure 1This is a flowchart of a battery interface preprocessing method described in some embodiments of this application.

[0031] refer to Figure 1 As shown, this application provides a battery interface preprocessing method, including: Step S1: Provide a battery as described above; Step S2: Charge the battery, or perform multiple charge and discharge cycles on the battery.

[0032] In some embodiments of this application, charging the battery or performing multiple charge and discharge cycles on the battery needs to be controlled within the capacity range provided by the lithium source material.

[0033] In some embodiments of this application, other methods may also be used for interface pretreatment of the lithium battery. The specific method needs to be selected based on different materials, time and economic costs, battery requirements, etc.

[0034] In some embodiments of this application, the charging current during interface preprocessing of the battery is DC or DC superimposed with sinusoidal AC.

[0035] In some embodiments of this application, the battery is charged at a temperature of 20 to 25 degrees Celsius, and the charging rate is 0.1C to 0.3C. The specific charging rate can be selected according to different cathode materials and lithium source materials.

[0036] In some embodiments of this application, at least one of the charging current and discharging current for multiple charge and discharge cycles of the battery is AC or DC superimposed sinusoidal AC.

[0037] In some embodiments of this application, when the battery undergoes multiple charge and discharge cycles, the charging temperature is 20 to 25 degrees Celsius, the charging rate is 0.1C to 0.3C, and when the charging current is DC superimposed with sinusoidal AC, the charging frequency is 1kHz to 1MHz, and the charging amplitude is 50% of the DC charging rate. Similarly, when the battery undergoes multiple charge and discharge cycles, the discharging temperature is 20 to 25 degrees Celsius, the discharging rate is 0.1C to 0.3C, and when the discharging current is DC superimposed with sinusoidal AC, the discharging frequency is 1kHz to 1MHz, and the discharging amplitude is 50% of the DC discharging rate.

[0038] Preferably, in the technical solution of this application, the battery is subjected to multiple charge and discharge cycles, and both the charging current and the discharging current are DC superimposed sinusoidal AC.

[0039] The technical solution of this application can greatly improve the quality of the solid electrolyte interface film in a primary battery system. Compared with ordinary primary batteries, it can significantly suppress battery self-discharge and solve or delay the voltage hysteresis problem that occurs after long-term storage of primary batteries.

[0040] Example 1 A coin cell with a theoretical capacity of 200 mAh was assembled in an argon-filled glove box. The positive electrode active material of the coin cell was a mixture of primary battery material and lithium source material at a capacity ratio of 9:1; the negative electrode active material was lithium metal. Specifically, the primary electrode material was electrolytic manganese dioxide, with a theoretical capacity of 308 mAh / g; the lithium source material was lithium iron phosphate, with an effective delithiation specific capacity of 145 mAh / g during the first charge.

[0041] The relationship between capacity ratio and mass ratio is as follows: Actual design capacity percentage ÷ theoretical gram capacity = mass of material; Specifically: The amount of manganese dioxide used in the positive electrode is determined based on the net discharge capacity (180mAh) after deducting the pre-treatment charge from the total capacity of 200mAh, that is: 180mAh ÷ 308mAh / g ≈ 0.584g.

[0042] The amount of lithium source material used in the positive electrode is: 20mAh ÷ 145mAh / g ≈ 0.138g.

[0043] That is, in this embodiment, the actual mass ratio of manganese dioxide to lithium iron phosphate used in the positive electrode active material of the battery is approximately 81:19.

[0044] Manganese dioxide and lithium iron phosphate were mixed in the above proportions to make a positive electrode sheet, and lithium metal was used as the negative electrode. The coin cell was assembled in a glove box filled with argon gas.

[0045] After the assembled battery was left to stand for 24 hours, an EIS test was performed to obtain the solid electrolyte interfacial membrane impedance of the battery without complete interface pretreatment.

[0046] The assembled battery then underwent interface pretreatment within a 16mAh capacity range, specifically by charging the battery with a 0.1C current superimposed with sinusoidal AC (frequency 50kHz, amplitude ±10mA). After charging, the battery was subjected to EIS testing.

[0047] Example 2 The mass ratio calculation and coin cell preparation in this embodiment are the same as in Example 1. The difference is that in this embodiment, fluorinated carbon is used as the primary battery material, and lithium manganese oxide is used as the lithium source material. The mass ratio is 59:41. After fabrication, the interface pretreatment scheme involves charging the battery with a 0.2C current superimposed with sinusoidal AC (frequency 50kHz, amplitude ±20mA) within a 16mAh capacity range, followed by discharging the battery with 0.2C. After two cycles, the battery is subjected to EIS testing.

[0048] The EIS test results for Implementation Case 1 and Example 2 are as follows: Figure 2 and Figure 3 As shown in the figure, it is clear that compared to the battery without interface pretreatment, the impedance of the solid electrolyte interface film of the battery after interface pretreatment is significantly reduced, proving that the technical solution of this application can greatly improve the quality of the solid electrolyte interface film in the primary battery system.

[0049] The above describes some of the embodiments of this application in detail. However, this application is not limited to the specific details of the above embodiments. Within the scope of the technical concept of this application, various simple modifications can be made to the technical solution of this application, and these simple modifications all fall within the protection scope of this application.

[0050] It should also be noted that the various specific technical features described in the above embodiments can be combined in any suitable manner without contradiction. To avoid unnecessary repetition, this application will not describe the various possible combinations separately.

[0051] Furthermore, various different implementations of this application can be combined in any way, as long as they do not violate the spirit of this application, they should also be regarded as the content of this application.

[0052] In summary, after reading this application, those skilled in the art will understand that the foregoing application content is presented by way of example only and is not restrictive. Although not explicitly stated herein, those skilled in the art will understand that this application is intended to encompass various reasonable changes, improvements, and modifications to the embodiments. These changes, improvements, and modifications are all within the spirit and scope of the exemplary embodiments of this application.

[0053] It should be understood that the term "and / or" as used in this embodiment includes any or all combinations of one or more of the associated listed items. It should be understood that when an element is referred to as "connected" or "coupled" to another element, it may be directly connected or coupled to the other element, or there may be an intermediate element.

[0054] It should also be understood that the terms “comprising,” “containing,” “including,” or “comprise”, when used in this application, indicate the presence of the described features, wholes, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, components, and / or groups thereof.

[0055] It should also be understood that although the terms first, second, third, etc., may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. Therefore, without departing from the teachings of this application, a first element in some embodiments may be referred to as a second element in other embodiments. The same reference numerals or the same reference signs denote the same elements throughout the specification.

[0056] Furthermore, this application specification describes exemplary embodiments by referring to idealized exemplary cross-sectional views and / or plan views and / or perspective views. Therefore, differences from the illustrated shapes are foreseeable due to factors such as manufacturing techniques and / or tolerances. Therefore, exemplary embodiments should not be construed as limited to the shapes of the regions shown herein, but should include deviations in shape caused, for example, by manufacturing processes. Thus, the regions shown in the figures are substantially schematic, and their shapes are not intended to illustrate the actual shapes of the regions of the device, nor are they intended to limit the scope of the exemplary embodiments.

Claims

1. A battery, characterized in that, include: The device comprises a positive electrode and a negative electrode. The positive electrode includes a positive electrode current collector and a positive electrode active material coated on the positive electrode current collector. The positive electrode active material includes a primary battery material and a lithium source material. The negative electrode includes a negative electrode current collector and a negative electrode active material coated on the negative electrode current collector.

2. The battery as described in claim 1, characterized in that, The capacity provided by the primary battery material accounts for more than or equal to 90% of the total capacity of the battery.

3. The battery as described in claim 1, characterized in that, The primary battery material includes any one of manganese dioxide, vanadium pentoxide, carbon fluoride, iron disulfide, and copper oxide.

4. The battery as described in claim 1, characterized in that, The lithium source material includes any one of the following: lithium iron phosphate, lithium manganese phosphate, nickel-cobalt-manganese ternary materials, nickel-cobalt-aluminum ternary materials, lithium-rich manganese-based materials, lithium manganese oxide, lithium oxalate, lithium peroxide, lithium nickel oxide, lithium copper oxide, and lithium sulfide.

5. The battery as described in claim 1, characterized in that, The negative electrode material includes any one of lithium metal, lithium metal foil, and lithium alloy.

6. A battery interface pretreatment method, characterized in that, include: Provide a battery as described in any one of claims 1 to 5; The battery is charged within the capacity range provided by the lithium source material, or the battery is subjected to multiple charge and discharge cycles.

7. The interface preprocessing method as described in claim 6, characterized in that, The charging current during interface pretreatment of the battery is either DC or DC superimposed with sinusoidal AC.

8. The interface preprocessing method as described in claim 6, characterized in that, The charging temperature for charging the battery is 20 to 25 degrees Celsius, and the charging rate for charging the battery is 0.1C to 0.3C.

9. The interface preprocessing method as described in claim 6, characterized in that, At least one of the charging current and discharging current during multiple charge and discharge cycles of the battery is a superimposed DC sinusoidal AC current.

10. The interface preprocessing method as described in claim 9, characterized in that, When the battery undergoes multiple charge and discharge cycles, the charging temperature is 20 to 25 degrees Celsius, the charging rate is 0.1C to 0.3C, and when the charging current is DC superimposed with sinusoidal AC, the charging frequency is 1kHz to 1MHz, and the charging amplitude is 50% of the DC charging rate. Similarly, when the battery undergoes multiple charge and discharge cycles, the discharging temperature is 20 to 25 degrees Celsius, the discharging rate is 0.1C to 0.3C, and when the discharging current is DC superimposed with sinusoidal AC, the discharging frequency is 1kHz to 1MHz, and the discharging amplitude is 50% of the DC discharging rate.

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