Sulfur-containing polymer additive, electrolyte and battery
By using sulfur-containing polymer additives in lithium metal batteries to construct a three-dimensional network SEI film and a high-voltage antioxidant interface, the problems of activity loss and dendrite growth in lithium metal anodes are solved, and the long cycle life and stability of the battery are improved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- DKJ NEW ENERGY S & T CO LTD
- Filing Date
- 2025-12-16
- Publication Date
- 2026-04-21
AI Technical Summary
Existing lithium metal anode applications suffer from rapid loss of active lithium and lithium dendrite growth, leading to challenges in battery cycle life and safety. Existing additives cannot stably improve battery interface properties in the long term.
By using sulfur-containing polymer additives, a synergistic mechanism of "negative electrode construction - positive electrode stabilization" is constructed by forming a three-dimensional network SEI film on the negative electrode side and providing high-pressure anti-oxidation on the positive electrode side, thereby improving the battery interface stability and inhibiting irreversible loss of active materials and dendrite growth.
It significantly improves the cycle life and stability of lithium metal batteries, enhances charge and discharge efficiency and long-cycle capacity retention, suppresses lithium dendrite growth, and ensures the long-term stability and safety of the battery.
Smart Images
Figure CN121895579A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of battery technology, specifically relating to a sulfur-containing polymer additive, an electrolyte, and a battery. Background Technology
[0002] Electrochemical energy storage is not geographically limited and has the advantages of precise control and rapid response, ensuring the stable and efficient operation of future new power systems based primarily on new energy sources. Furthermore, high-energy batteries also contribute to the further development of new energy vehicles and reduce carbon emissions from automobiles. Lithium metal anodes possess high theoretical energy density (3860 mAh g⁻¹). -1 With its low electrode potential (-3.04 V vs. SHE), and given the current technological advancements and the demand for high energy density in batteries, there is an urgent need to develop new lithium metal anodes to better meet the needs of energy system transformation and social electrification.
[0003] However, the application of lithium metal anodes also has some problems, such as: (1) rapid loss of active lithium. Highly active metallic lithium will spontaneously react with the liquid electrolyte to form a relatively inert interface electrolyte layer (SEI). However, the stability of this SEI is poor, and the continuous breaking and rebuilding of the structure can easily lead to rapid irreversible loss of active lithium, accelerating the decay of battery capacity. (2) Lithium dendrite growth problem. Due to the uneven microstructure of the SEI, the lithium reaction kinetics are inconsistent at different locations, and uneven lithium deposition is prone to occur at the interface, forming lithium dendrites. Irregular lithium dendrites have a large specific surface area and high reactivity. This poses a challenge to the cycle life and safety of the battery. Developing high-performance electrolytes to enhance the properties of the electrode interface layer can greatly improve the battery cycle performance. After years of exploration, the simplest and most effective way to improve the electrolyte is to add additives to the electrolyte to improve the cycle performance of the battery.
[0004] Currently, lithium battery electrolyte additives are mainly classified by function into positive / negative electrode film-forming additives, high / low temperature additives, overcharge protection additives, flame retardant additives, and other additives (such as water removal, HF removal, and wetting enhancement). Among these, positive / negative electrode film-forming additives are continuously consumed in the electrolyte, resulting in limited long-term improvement of the electrode interface. Other types of additives primarily enhance single battery characteristics; inappropriate amounts can negatively impact battery cycle performance. Existing additive technologies have limited effectiveness, cannot provide long-term stable performance, and cannot achieve long-term battery stability. Therefore, there is an urgent need to develop a performance-improving additive that can persist for an extended period. Summary of the Invention
[0005] The purpose of this invention is to overcome the shortcomings of the prior art and provide a sulfur-containing polymer additive, an electrolyte, and a battery. The electrolyte additive provided by this invention can improve the instability of the negative electrode interface in metal secondary batteries, inhibit irreversible loss of active materials, suppress dendrite growth in the metal negative electrode, improve the battery's charge-discharge efficiency, long-cycle capacity retention, and stability, and greatly enhance the cycle life of secondary batteries.
[0006] This invention provides the following technical solution:
[0007] In a first aspect, a sulfur-containing polymer additive is provided, said sulfur-containing polymer additive comprising one or more polysulfides represented by the following general structural formula:
[0008]
[0009] In the formula, X and Y are carbon atoms or carbon-containing groups; Z is a carbon chain -(C)- b Alternatively, it may contain any one of the following groups: sulfur, boron, aluminum, oxygen, nitrogen, phosphorus, or silicon; b represents the number of carbon atoms attached, and b ≥ 0; R1, R2, R3, and R4 are substituent groups.
[0010] Furthermore, when X and Y are carbon-containing groups, X and Y are independently selected from the carbon chain -(C)- a , where 'a' represents the number of connected carbon atoms, a > 1; or independently selected from any one of the carbon-carbon double bonds, carbon-carbon triple bonds, phenyl, ether, aldehyde, carbonyl, carboxyl, ester, amide, imino, or cyano carbon-containing groups; R1, R2, R3 and R4 are each independently selected from any one or more of hydrogen, halogen, carbonyl, ester, ether, ketone, carboxyl, amino, nitro, nitrile, amide, sulfonic acid, disulfide bond, phosphine, phosphate ester, silyl or phenyl.
[0011] Furthermore, when X and Y are carbon atoms, R1, R2, R3 and R4 are each independently selected from any one of hydrogen, halogen, carbonyl, ester, ether, ketone, carboxyl, amino, nitro, nitrile, amide, sulfonic acid, disulfide bond, phosphine, phosphate ester, silicon, or phenyl.
[0012] Furthermore, when Z is a carbon chain -(C)- b When b≥1, a substituent R is attached to the carbon chain, and the substituent R is selected from any one of hydrogen, halogen, carbonyl, ester, ether, ketone, carboxyl, amino, nitro, nitrile, amide, sulfonic acid, disulfide bond, phosphine, phosphate ester, silyl or phenyl.
[0013] Furthermore, Z is selected from any one of heteroatoms containing sulfur, boron, aluminum, oxygen, nitrogen, phosphorus, or silicon, as well as their functional groups or carbon chains.
[0014] In a second aspect, an electrolyte is provided, comprising a matrix electrolyte and an additive, wherein the additive is a sulfur-containing polymer additive as described in any one of the first aspects.
[0015] Furthermore, the sulfur-containing polymer additive accounts for 0.01 wt% to 15 wt% of the mass of the matrix electrolyte.
[0016] Furthermore, the matrix electrolyte includes any one or more of ester electrolytes, ether electrolytes, sulfone electrolytes, nitrile electrolytes, or amide electrolytes.
[0017] Thirdly, a battery is provided, comprising a positive electrode, a negative electrode, and a separator, wherein the battery further comprises the electrolyte described in any of the second aspects.
[0018] Furthermore, the battery includes a metal secondary battery with one or more of an alkali metal active negative electrode and its alloy, a metal-carbon composite or a metal composite as the negative electrode, or a metal secondary battery with only conductive foil.
[0019] Furthermore, the charge carriers in the metal secondary battery system include L i+ Na + K + Zn 2+ Mg 2+ Ca 2+ Al 3+ Any one or a mixture of several of them.
[0020] Compared with the prior art, the beneficial effects of the present invention are: (1) This invention uses sulfur-containing polymer additives to effectively improve the stability of the battery negative electrode interface through a synergistic mechanism of "negative electrode construction - positive electrode stabilization", thereby achieving long-cycle stability of the battery under high voltage. This invention uses sulfur-containing polymer additives with polysulfide in the general formula. On the negative electrode side, the polymer properties of polysulfide enable it to electrochemically crosslink in situ on the lithium surface, forming a mechanically stable and dense three-dimensional network SEI film, replacing the unstable natural SEI film. On the positive electrode side, through molecular design (such as the introduction of benzene rings), polysulfide has excellent high-voltage oxidation resistance and can exist stably at the positive electrode interface without decomposition, thus simultaneously achieving integrated protection of the high-voltage positive electrode and the lithium metal negative electrode, fundamentally improving the interface stability of the whole battery. (2) The sulfur-containing polymer additive provided by this invention can inhibit the irreversible loss of active materials. The polysulfide used in this invention inhibits the loss of active materials by constructing an efficient barrier. The stable SEI film formed greatly reduces the side reactions between lithium metal and electrolyte and the generation of "dead lithium", significantly improving the coulombic efficiency of lithium deposition / stripping and preserving the negative electrode active materials. At the same time, the high voltage stability of polysulfide on the positive electrode side inhibits the oxidative decomposition of electrolyte and the degradation of positive electrode structure, protecting the positive electrode capacity. This bidirectional protection mechanism together ensures the overall capacity and cycle life of the battery. (3) This invention can suppress dendrite growth in metal anodes. The polysulfide used in this invention physically suppresses dendrites by constructing a strong "artificial interface layer". Its in-situ formed three-dimensional network SEI film has high mechanical strength, which can effectively resist and passivate dendrite penetration; at the same time, the film layer has excellent uniformity and lithium-ion conductivity, which can guide the uniform distribution and deposition of lithium ions, eliminating the driving force for dendrite growth from the root. The combined effect of this physical barrier and ion flow regulation ensures the smooth and safe deposition of lithium metal; (4) This invention greatly improves the capacity retention rate and cycle life of secondary batteries. This invention uses one or more composites of alkali metal active negative electrode and alloy, metal carbon composite, and metal composite as negative electrode, or metal secondary battery with only conductive foil, which can effectively improve the cycle performance of the battery, increase the battery life, and ensure the long-term stable operation of the battery. Attached Figure Description
[0021] Figure 1 These are the cycle performance diagrams of lithium metal symmetric batteries in Embodiment 2 and Comparative Example 1 of the present invention; Figure 2 These are the cycle performance diagrams of lithium metal batteries in Embodiment 2 and Comparative Example 1 of the present invention; Figure 3 This is a scanning electron microscope image of the lithium deposition morphology in Comparative Example 1 of this invention; Figure 4 This is a scanning electron microscope image of the lithium deposition morphology in Example 2 of the present invention. Detailed Implementation
[0022] The present invention will be further described below with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and should not be used to limit the scope of protection of the present invention.
[0023] In the description of this invention, unless otherwise stated, "a plurality of" means two or more. The terms "comprising," "having," "containing," etc., as used herein are open-ended, meaning they include but are not limited to.
[0024] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Every smaller range between any stated value or intermediate value within a stated range, and any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.
[0025] This invention provides a method for preparing an electrolyte, comprising the following steps: The preparation process of the electrolyte of this invention is carried out in a glove box with a moisture content of less than 0.1 ppm and an oxygen content of less than 0.1 ppm. A sulfur-containing polymer additive is added to the matrix electrolyte, wherein the mass of the sulfur-containing polymer additive accounts for 0.01 wt% to 15 wt% of the mass of the matrix electrolyte. The mixture is magnetically stirred at room temperature for 12 hours until homogeneous, and then the electrolyte is obtained and sealed in a glove box for storage.
[0026] This invention provides a battery and its testing method. The battery assembly is carried out in a glove box with a moisture content of less than 0.1 ppm and an oxygen content of less than 0.1 ppm.
[0027] In some possible embodiments, the battery is a lithium-lithium symmetric battery based on the CR2032 coin cell configuration, with both positive and negative electrodes using 500 μm thick lithium sheets, a Celgard 2400 separator, and 50 μL of electrolyte. After assembly, the lithium / lithium symmetric battery is allowed to stand at room temperature for 8 hours, followed by a constant rate test at 1C, with a cycle voltage range of 2.5–3.8 V. A 2-minute rest period is set between each charge / discharge cycle.
[0028] In some possible embodiments, the battery employs a full cell based on the CR2025 coin cell configuration, with commercially available lithium iron phosphate as the positive electrode, a 500 μm thick lithium sheet as the negative electrode, a Celgard 2400 separator, and 50 μL of electrolyte. After assembly, the full cell is first allowed to stand at room temperature for 8 hours, followed by a constant rate test at 1C, with a cycle voltage range of 2.5–3.8 V. A 2-minute rest period is set between each charge / discharge cycle.
[0029] In the above technical solution, the positive electrode preparation process includes the following steps: The active material, conductive agent, and binder are mixed in a specific ratio and then coated onto aluminum foil. In some possible embodiments, the active material is lithium iron phosphate, the conductive agent is acetylene black, and the binder is polytetrafluoroethylene, with the active material, conductive agent, and binder mixed in a mass ratio of 8:1:1.
[0030] Example 1
[0031] This embodiment provides an electrolyte, wherein the base electrolyte is an ester-based electrolyte, and the additive is polyphenylene sulfide (PPS), wherein the mass of PPS accounts for 0.1 wt% of the mass of the ester-based electrolyte. The structural formula of PPS is shown below:
[0032]
[0033] The lithium salt in the ester electrolyte is 1.0 mol / L lithium hexafluorophosphate (LiPF6), and the solvent is a mixed solvent of ethylene carbonate (EC), ethyl methyl carbonate (EMC), and diethyl carbonate (DMC) in a volume ratio of 1:1:1.
[0034] In a glove box with a moisture content of less than 0.1 ppm and an oxygen content of less than 0.1 ppm, polyphenylene sulfide is added to an ester electrolyte and magnetically stirred at room temperature for 12 hours. After the mixture is homogeneous, the target electrolyte is obtained and sealed in a glove box for storage.
[0035] Examples 2 to 5
[0036] Examples 2-5 were prepared based on the electrolyte components and preparation method provided in Example 1. The difference is that the mass ratio of the additives to the mass of the ester electrolyte in Examples 2-5 is different, as shown in Table 1.
[0037] Example 6
[0038] This embodiment provides an electrolyte, in which the base electrolyte is an ether-based electrolyte and the additive is polyphenylene sulfide, wherein the mass of polyphenylene sulfide accounts for 0.2 wt% of the mass of the ether-based electrolyte.
[0039] The lithium salt in the ether electrolyte is 1.0 mol / L lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), and the solvent is a mixed solvent of ethylene glycol dimethyl ether (DME) and 1,3-dioxolane (DOL) in a volume ratio of 1:1.
[0040] In a glove box with a moisture content of less than 0.1 ppm and an oxygen content of less than 0.1 ppm, polyphenylene sulfide is added to an ether electrolyte and magnetically stirred at room temperature for 12 hours. After the mixture is homogeneous, the target electrolyte is obtained and sealed in a glove box for storage.
[0041] Example 7
[0042] This embodiment provides an electrolyte based on the electrolyte and preparation method of Example 1. The difference is that the additive in this embodiment is polyarylene sulfide sulfone, which accounts for 0.2 wt% of the mass of the ester electrolyte. The structural formula of polyarylene sulfide sulfone is shown below:
[0043]
[0044] Example 8
[0045] This embodiment provides an electrolyte based on the electrolyte and preparation method of Example 1. The difference is that the additive in this embodiment is polyarylether thioether ketone, which accounts for 0.2 wt% of the mass of the ester electrolyte. The structural formula of polyarylether thioether ketone is shown below:
[0046]
[0047] Example 9
[0048] This embodiment provides an electrolyte based on the electrolyte and preparation method of Example 1. The difference is that the additive in this embodiment is polyarylene sulfide amide, which accounts for 0.2 wt% of the mass of the ester electrolyte. The structural formula of polyarylene sulfide amide is shown below:
[0049]
[0050] Example 10
[0051] This embodiment provides an electrolyte based on the electrolyte and preparation method of Example 1. The difference is that the additive in this embodiment is polyarylene sulfide nitrile, which accounts for 0.2 wt% of the mass of the ester electrolyte. The structural formula of polyarylene sulfide nitrile is shown below:
[0052]
[0053] Comparative Example 1
[0054] This comparative example provides an electrolyte based on the electrolyte and preparation method of Example 1. The difference is that the electrolyte in this comparative example does not contain any additives and is composed entirely of ester electrolytes.
[0055] Comparative Example 2
[0056] This comparative example provides an electrolyte based on the electrolyte and preparation method of Examples 1 and 6. The difference is that the electrolyte of this comparative example does not contain additives and is composed entirely of ether electrolyte.
[0057] Application examples
[0058] In this application example, the electrolytes prepared in Examples 1-10 and Comparative Examples 1-2 were used in full cells based on the CR2025 coin cell configuration, with each electrolyte being 50 μL. At room temperature, a constant rate test method was used, with a test rate of 1 C and a cycle voltage range of 2.5–3.8 V. A 2-minute rest period was set between each charge-discharge cycle. The test results are shown in Table 1.
[0059] Table 1 Cycle life test results of different embodiments
[0060] The mass percentage refers to the percentage of the additive's mass relative to the mass of the matrix electrolyte, and the cycle life is calculated based on an 80% capacity retention rate.
[0061] As shown in Table 1, the cycle performance of Examples 1-10 is significantly better than that of Comparative Examples 1-2, indicating that the use of ester-based and ether-based electrolytes, along with the introduction of polysulfide additives, can improve battery stability. The cycle life of Examples 1-6 is significantly better than that of Comparative Examples 1-2, indicating that the introduction of polyphenylene sulfide additives can greatly improve the interfacial stability of the lithium metal anode in ester-based electrolytes and extend the electrode's stable cycle time. The introduction of polyphenylene sulfide additives into ester-based electrolytes can significantly improve the cycle life of lithium iron phosphate lithium metal full batteries. In Example 2, the cycle life is optimal when the mass of polyphenylene sulfide accounts for 0.2 wt% of the ester-based electrolyte.
[0062] Based on the testing method for lithium iron phosphate lithium metal full cells, this application example uses the electrolytes of Example 2 and Comparative Example 1 for cycle life testing. Figure 1 The figures shown are the specific cyclic data for Example 2 and Comparison 1. Figure 1 As shown in Table 1, at a 1C test rate, the cycle life of lithium metal full cells based on lithium iron phosphate increased from 183 to 1137 cycles (based on 80% capacity retention) after adding polyphenylene sulfide (PPS) additive, which is 6.2 times that of full cells using blank ester electrolyte. This indicates that the introduction of PPS can effectively improve the cycle stability of lithium metal full cells, alleviate the irreversible loss of active lithium, and improve the cycle capacity retention and cycle life of the battery.
[0063] Based on the testing method for lithium-lithium symmetric batteries, this application example uses the electrolytes of Example 2 and Comparative Example 1 to conduct cycle life tests. Figure 2 This is a cycle performance graph of the lithium metal battery for Example 2 and Comparative Example 1. (Source: [Insert Source Here]) Figure 2It was found that introducing 0.2 wt% polyphenylene sulfide (PPS) additive into the electrolyte extended the stable cycle life of the lithium-ion symmetric battery from less than 300 hours to over 600 hours, while also exhibiting a lower polarization voltage level (15.5 mV at 600 hours of cycling). The shorter cycle life without the additive can be attributed to the inability of the lithium metal electrode to form a stable interfacial film in the electrolyte. Prolonged side reactions led to the formation of thicker byproducts at the interface, increasing the resistance to interfacial ion transport. Simultaneously, these long-term side reactions also caused electrolyte drying, ultimately leading to battery failure. The improved cycle performance of the lithium-ion battery after introducing PPS additive confirms that 0.2 wt% PPS additive can effectively improve the stability of the lithium metal electrode, further demonstrating that PPS additive can enhance battery cycle life.
[0064] In the lithium-lithium symmetric battery cycling test system, after cycling 20 times using the electrolytes of Example 2 and Comparative Example 1, the lithium-deposited side electrode was disassembled, cleaned with solvent, and thoroughly dried before being characterized by scanning electron microscopy.
[0065] Figure 3 The image shows the lithium deposition morphology after 20 cycles using the electrolyte provided in Comparative Example 1. Figure 3 It is evident that in ester-based electrolytes without additives, a significant side reaction layer covers the lithium deposition surface. This layer is porous and contains numerous micropores, confirming the continuous and intense side reactions between the lithium metal interface and the electrolyte. The porous structure also fails to passivate the lithium metal surface, leading to the continuous accumulation of the side reaction layer. This results in the sustained loss of active lithium and deterioration of interfacial kinetics, ultimately causing a decline in battery cycle performance.
[0066] Figure 4 The image shows a scanning electron microscope (SEM) image of the lithium deposition morphology after 20 cycles in the electrolyte provided in Example 2. Figure 4 It is known that after introducing 0.2 wt% polyphenylene sulfide into the ester electrolyte, a relatively dense film is covered on the surface of lithium metal, and the film has a branched structure, which can improve the mechanical strength of the interfacial film. Therefore, the side reactions at the electrode interface can be alleviated, thereby ensuring the long-term cycle stability of the electrode and improving the cycle life of the battery.
[0067] The polysulfide additive used in this application example achieves long-term cycle stability of the battery at high voltage through a unique "negative electrode construction-positive electrode stabilization" synergistic mechanism. Its mechanism of action is as follows:
[0068] On the negative electrode side: an in-situ "crosslinked polymer-reinforced interface film" is constructed. During the first charge and discharge of the battery, multiple sulfide bonds in the polysulfide molecular chain undergo preferential, multi-step reduction reactions at the low potential of the lithium metal negative electrode. This process differs from the simple decomposition of small molecule sulfides; it resembles an in-situ electrochemical crosslinking polymerization process. The result is the formation of a solid electrolyte interface film with a three-dimensional network structure, rich in lithium-ion conductors such as Li₂S and LiPS, on the negative electrode surface. This polymer composite interface film possesses excellent mechanical strength, superior flexibility, and extremely low electrolyte solubility. It effectively resists lithium dendrite penetration and maintains the structural integrity of the interface during long-term cycling, thereby significantly reducing the continuous consumption of active lithium and electrolyte, laying the foundation for a long cycle life.
[0069] On the positive electrode side: "High-voltage stabilization" is achieved through molecular designability. By rationally designing the molecular structure of polysulfides (e.g., introducing stabilizing units with low HOMO energy levels, such as aromatic rings, into the main chain or side chains), the overall molecule's antioxidant capacity can be significantly higher than that of small-molecule sulfides. This allows the selected polysulfide to exist stably at the high-voltage positive electrode interface, avoiding a series of side reactions caused by its own oxidative decomposition. Its stable existence not only protects the electrolyte, but its decomposition products (if present) may also contribute to the formation of a thin and dense CEI film, further suppressing side reactions between the positive electrode material and the electrolyte, and protecting the positive electrode structure.
[0070] The polysulfide provided by this invention stabilizes the lithium deposition / stripping process by forming a robust three-dimensional polymer interface film on the negative electrode side; simultaneously, its high chemical stability on the positive electrode side ensures the stability of the high-voltage interface. This synergistic and integrated protection of the two key electrodes of the battery jointly breaks through the cycle life bottleneck of high-energy-density lithium metal batteries, achieving significant technological progress.
[0071] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.
Claims
1. A sulfur-containing polymer additive, characterized in that, The sulfur-containing polymer additive includes one or more polysulfides represented by the following general structural formula: ； In the formula, X and Y are carbon atoms or carbon-containing groups; Z is a carbon chain -(C)- b Or containing any one of the following groups: sulfur, boron, aluminum, oxygen, nitrogen, phosphorus, or silicon. b Represents the number of carbon atoms bonded. b ≥0; R1, R2, R3 and R4 are substituent groups.
2. The sulfur-containing polymer additive according to claim 1, characterized in that, When X and Y are carbon-containing groups, X and Y are independently selected from the carbon chain -(C)- a ,in a Represents the number of connected carbon atoms. a >1; or independently selected from any one of the carbon-carbon double bonds, carbon-carbon triple bonds, phenyl, ether, aldehyde, carbonyl, carboxyl, ester, amide, imino, or cyano carbon-containing groups; R1, R2, R3 and R4 are each independently selected from any one or more of hydrogen, halogen, carbonyl, ester, ether, ketone, carboxyl, amino, nitro, nitrile, amide, sulfonic acid, disulfide bond, phosphine, phosphate ester, silyl or phenyl.
3. The sulfur-containing polymer additive according to claim 1, characterized in that, When X and Y are carbon atoms, R1, R2, R3 and R4 are each independently selected from any one of hydrogen, halogen, carbonyl, ester, ether, ketone, carboxyl, amino, nitro, nitrile, amide, sulfonic acid, disulfide bond, phosphine, phosphate ester, silicon or phenyl.
4. The sulfur-containing polymer additive according to claim 1, characterized in that, When Z is a carbon chain -(C)- b ,and b When ≥1, the carbon chain is attached to a substituent R, which is selected from any one of hydrogen, halogen, carbonyl, ester, ether, ketone, carboxyl, amino, nitro, nitrile, amide, sulfonic acid, disulfide bond, phosphine, phosphate ester, silyl, or phenyl.
5. The sulfur-containing polymer additive according to claim 1, characterized in that, Z is selected from any one of heteroatoms containing sulfur, boron, aluminum, oxygen, nitrogen, phosphorus, or silicon, as well as their functional groups or carbon chains.
6. An electrolyte comprising a matrix electrolyte and additives, characterized in that, The additive is the sulfur-containing polymer additive as described in any one of claims 1 to 5.
7. The electrolyte according to claim 6, characterized in that, The sulfur-containing polymer additive accounts for 0.01 wt% to 15 wt% of the mass of the matrix electrolyte.
8. The electrolyte according to claim 6, characterized in that, The matrix electrolyte includes any one or more of ester electrolytes, ether electrolytes, sulfone electrolytes, nitrile electrolytes, or amide electrolytes.
9. A battery comprising a positive electrode, a negative electrode, and a separator, characterized in that, The battery further includes the electrolyte as described in any one of claims 6 to 8.
10. The battery according to claim 9, characterized in that, The battery includes a metal secondary battery with one or more of the following as the negative electrode: an alkali metal active negative electrode and its alloy, a metal-carbon composite or a metal composite, or a metal secondary battery with only conductive foil.