In-situ curing electrolyte, polymer electrolyte and solid-state battery
By using chain transfer agents and stabilizing additives with specific structures in the in-situ curing electrolyte, the uniformity problem of in-situ curing polymer electrolyte is solved, which improves conductivity and stability and reduces costs.
Patent Information
- Application Number
- CN202510397645.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-31
- Publication Date
- 2025-07-08
AI Technical Summary
In the prior art, the uniformity of the in-situ cured polymer electrolyte is lacking, resulting in low conductivity at room temperature, unstable chain transfer agents and high cost.
A chain transfer agent containing -C(=S)S- or -SC(=S)S- structure is used, and a stable additive such as hydrofluoric acid removal additive is added to adjust the pH value of the high-temperature curing stage, control the polymerization reaction, and prepare a polymer electrolyte with uniform molecular weight distribution.
The room temperature conductivity of polymer electrolytes and the stability of chain transfer agents are improved, the cost is reduced, and a more uniform molecular weight distribution is achieved.
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Figure CN120280549A_ABST
Abstract
Description
Technical Field
[0001] The present disclosure relates to the technical field of batteries, and in particular, to an in-situ cured electrolyte, a polymer electrolyte, and a solid-state battery. Background Art
[0002] With the development of science and technology, batteries have been increasingly widely used. To improve battery safety, energy density, cycle stability, and simplify the manufacturing process, etc., in-situ cured polymer electrolytes are usually required in batteries.
[0003] Due to the randomness of free radical polymerization, the uniformity of in-situ cured polymer electrolytes is lacking. It has been reported in related technologies that the molecular weight distribution of polymers can be controlled by adding a chain transfer agent. However, the inventors have found that using a general chain transfer agent easily leads to problems such as low conductivity of the polymer electrolyte at room temperature, instability of the chain transfer agent, and high cost. Summary of the Invention
[0004] The object of the present invention is to improve the conductivity of the polymer electrolyte at room temperature, improve the stability of the chain transfer agent, and reduce the cost.
[0005] In a first aspect, an embodiment of the present invention provides an in-situ cured electrolyte, including a chain transfer agent, a stabilizing additive, a reactive monomer, an initiator, and an electrolyte.
[0006] Further, the stabilizing additive is a solvent that can adjust the pH value in the high-temperature curing stage. The stabilizing additive is preferably an acid-removing additive, and further preferably a hydrofluoric acid-removing additive.
[0007] In the above aspect and any possible implementation manner, a further implementation manner is provided. The chain transfer agent is a compound containing a -C(=S)S- or -SC(=S)S- structure, which helps to maintain a high free radical concentration in the polymerization system of the in-situ cured electrolyte, thereby achieving more effective polymerization control and ensuring that the polymer molecular weight increases linearly with the conversion rate.
[0008] A further implementation manner is provided. The transfer agent is further selected from one or more of dithiocarbonate-based chain transfer agents, trithiocarbonate-based chain transfer agents, xanthate-based chain transfer agents, and dithiocarbamate-based chain transfer agents;
[0009] Preferably, the chain transfer agent is selected from one or more of 2-cyano-2-propyl dodecyl trithiocarbonate, 2-cyano-2-propyl-4-cyanophenyl dithiocarbonate, 2-phenylpropyl thioester of thiobenzoic acid, 2-cyano-2-propyl benzodithio, S,S-dibenzyl trithiocarbonate, O-ethyl xanthate, and dithiocarbamate.
[0010] In the above aspects and any possible implementation manners, a further implementation manner is provided, wherein the chain transfer agent includes a polythiocarbonate chain transfer agent.
[0011] The chain transfer agent is preferably a dithiocarbonate chain transfer agent or a trithiocarbonate chain transfer agent.
[0012] More preferably, the chain transfer agent is selected from one or more of 2-cyano-2-propyl dodecyl trithiocarbonate, 4-cyano-4-[(dodecylthio)thiocarbonyl]sulfanyl pentanoic acid, 2,2′-[methylthio bis(thio)]bis[2-methylpropanoic acid], 2-cyano-2-propyl-4-cyanophenyl dithiocarbonate, 2-cyano-2-propyl benzodithio, S,S-dibenzyl trithiocarbonate, and dithiocarbamate.
[0013] In the above aspects and any possible implementation manners, a further implementation manner is provided, wherein the mass fraction of the chain transfer agent in the in-situ cured electrolyte is 0.01%-1%, for example, it can be 0.01%, 0.015%, 0.018%, 0.02%, 0.025%, 0.03%, 0.035%, 0.04%, 0.045%, 0.055%, 0.06%, 0.65%, 0.07%, 0.08%, 0.1%, 0.12%, 0.15%, 0.2%, 0.25%, 0.28%, 0.3%, 0.32%, 0.35, 0.38%, 0.4%, 0.42%, 0.45%, 0.48%, 0.5%, 0.52, 0.55%, 0.58%, 0.6%, 0.65%, 0.7%, 0.75%, 0.8%, 0.85%, 0.9%, 0.95%, 1%; preferably 0.01-0.2%. It should be noted that if the mass fraction of the chain transfer agent is too low, it is likely to fail to achieve the purpose of reducing the relative molecular mass of the in-situ cured electrolyte. If the mass fraction of the chain transfer agent is too high, the polymerization rate will decrease significantly, and too many additives will deteriorate the battery performance.
[0014] In the above aspects and any possible implementation manners, a further implementation manner is provided, wherein the stabilizing additive is selected from acid-removing additives; further, the stabilizing additive is selected from hydrofluoric acid-removing additives;
[0015] Preferably, the stabilizing additive specifically includes one or more of isocyanate group compounds, siloxane compounds, silane compounds, phosphite compounds, and amine compounds. For example: p-toluenesulfonyl isocyanate, trimethylsilyl isocyanate, phenyl isocyanate, hexamethylene diisocyanate, toluene diisocyanate, trimethylsilyl isothiocyanate, aminoalkyl disiloxane, tris(trimethylsilyl) phosphate, methyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, tris(trimethylsilyl) phosphite, trimethyl phosphite, triethyl phosphite, triphenyl phosphite, phthalic anhydride, succinic anhydride, ethanolamine, etc. The stabilizing additive is an acid-inhibiting additive, which reduces the free HF concentration by directly reacting with HF, or optimizes the SEI film structure to inhibit the generation of acidic substances (such as HF) caused by the decomposition of the electrolyte, so as to maintain the stability of the electrolyte pH value, thereby protecting the chain transfer agent from being decomposed.
[0016] The mass fraction of the stabilizing additive in the in-situ cured electrolyte is 0.01%-1%; for example, it can be 0.01%, 0.015%, 0.018%, 0.02%, 0.025%, 0.03%, 0.035%, 0.04%, 0.045%, 0.055%, 0.06%, 0.65%, 0.07%, 0.08%, 0.1%, 0.12%, 0.15%, 0.2%, 0.25%, 0.28%, 0.3%, 0.32%, 0.35, 0.38%, 0.4%, 0.42%, 0.45%, 0.48%, 0.5%, 0.52, 0.55%, 0.58%, 0.6%, 0.65%, 0.7%, 0.75%, 0.8%, 0.85%, 0.9%, 0.95%, 1%; preferably 0.01-0.2%. It should be noted that if the mass fraction of the stabilizing additive is too low, it is likely to fail to achieve the purpose of reducing the risk of decomposition of the chain transfer agent. For example, when the stabilizing additive is an acid-removing additive, if the mass fraction of the acid-removing additive is too low, then in the high-temperature curing stage, the acid-reducing ability of the acid-removing additive may be limited, thus unable to ensure the stability of the chain transfer agent. If the mass fraction of the stabilizing additive is too high, it will cause deterioration of battery performance.
[0017] The reaction monomers in the in-situ cured electrolyte provided by the present invention include: at least one of vinyl monomers containing a carbonyl group, aromatic ring vinyl monomers, alkyl vinyl monomers, or vinyl monomers with a lone pair of electrons connecting oxygen / nitrogen in the reaction monomers;
[0018] The vinyl monomers connected to a carbonyl group or an aromatic ring are preferably acrylate monomers, amide monomers, aromatic vinyl monomers and their copolymer monomers, acrylonitrile monomers, such as: methyl methacrylate, 1,6 - hexanediol diacrylate, methyl acrylate, ethyl acrylate, butyl acrylate, polyethylene glycol methyl ether acrylate, 1,4 - butanediol diacrylate, ethoxylated trimethylolpropane triacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, dipentaerythritol pentaacrylate, dipentaerythritol hexaacrylate, acrylamide, N,N - methylenebisacrylamide, N - isopropylacrylamide, N,N - dimethylacrylamide, N - (2 - hydroxypropyl) methacrylamide, N - methylmaleimide, N - ethylmaleimide, caprolactam, butyrolactam, styrene, acrylonitrile, one or more of them; the vinyl monomers connected to a saturated carbon or a lone pair of electrons of oxygen / nitrogen are preferably one or more of vinyl ester monomers and vinyl pyridine monomers, such as: vinyl acetate, dimethyl allylmalonate, diethyl allylmalonate, 2 - vinylpyridine, 4 - vinylpyridine, 5 - ethyl - 2 - vinylpyridine, one or more of them.
[0019] The reaction monomers account for 5% - 90% of the mass fraction of the in - situ solidified electrolyte.
[0020] In the in - situ solidified electrolyte provided by the present invention, any commercial electrolyte can be selected.
[0021] Among them, the electrolyte accounts for 0% - 95% of the mass fraction of the in - situ solidified electrolyte. It should be noted that when the mass fraction of the electrolyte in the in - situ solidified electrolyte is 0%, the in - situ solidified electrolyte is applied to all - solid - state batteries, and the all - solid - state batteries can be charged and discharged without adding an electrolyte. In the in - situ solidified electrolyte provided by the present invention, any initiator can be selected. For example, the initiator can include one or more of azo initiators, organic peroxide initiators, and inorganic peroxide initiators; preferably azo initiators, organic peroxide initiators, and inorganic peroxide initiators; further preferably one or more of azodiisobutyronitrile, benzoyl peroxide, potassium persulfate, and ammonium persulfate.
[0022] Furthermore, the initiator accounts for 0.2% - 2% of the mass fraction of the reaction monomers.
[0023] In the above - mentioned aspects and any possible implementation manners, a further implementation manner is provided. The pH of the electrolyte is 6 - 8, preferably 6.5 - 7.5, and further preferably 7. The stability additive can adjust the pH value in the high - temperature curing stage, control the electrolyte to be neutral, reduce the risk of instability and easy decomposition of the chain transfer agent due to the increase in acidity in the high - temperature curing stage, and improve the stability of the chain transfer agent in the in - situ solidified electrolyte.
[0024] In a second aspect, an embodiment of the present invention provides an application of the above in-situ solidifying electrolyte in the preparation of a polymer electrolyte. For example, the polymer electrolyte can be directly obtained by high-temperature solidifying the in-situ solidifying electrolyte.
[0025] In a third aspect, an embodiment of the present invention provides a polymer electrolyte, wherein one end of the polymer electrolyte chain contains a dithio functional group and a trithio functional group. That is, when the chain transfer agent is a polythiocarbonate chain transfer agent, one end of the polymer electrolyte chain prepared from the in-situ solidifying electrolyte will contain a dithio functional group and a trithio functional group.
[0026] Further, the polymer electrolyte is a linear polymer, a crosslinked polymer or a graft polymer.
[0027] For the above aspects and any possible implementation manners, a further implementation manner is provided. The polydispersity index (PDI) of the molecular weight distribution of the polymer electrolyte is 1 - 1.8. For example: 1, 1.1, 1.15, 1.2, 1.25, 1.3, 1.35, 1.4, 1.45, 1.5, 1.55, 1.6, 1.65, 1.7, 1.8, preferably 1 - 1.4. For the above aspects and any possible implementation manners, a further implementation manner is provided. The number-average molecular weight range of the polymer electrolyte is 50,000 - 150,000. For example, the number-average molecular weight can be 50,000, 60,000, 70,000, 80,000, 90,000, 100,000, 110,000, 120,000, 130,000, 140,000, 150,000.
[0028] Or, the weight-average molecular weight range of the polymer electrolyte is 50,000 - 150,000. For example, the weight-average molecular weight can be 50,000, 60,000, 70,000, 80,000, 90,000, 100,000, 110,000, 120,000, 130,000, 140,000, 150,000.
[0029] Preferably, the ratio of the maximum weight-average molecular weight to the minimum weight-average molecular weight of the polymer electrolyte is 1 - 30.
[0030] In a fourth aspect, an embodiment of the present invention provides an application of the above in-situ solidifying electrolyte or the above polymer electrolyte in a battery.
[0031] In a fifth aspect, an embodiment of the present invention provides a lithium battery, including the above polymer electrolyte.
[0032] In a sixth aspect, an embodiment of the present invention provides a method for preparing a lithium battery, including the following steps:
[0033] Prepare the above in-situ solidifying electrolyte;
[0034] Inject the above in-situ solidified electrolyte into the battery, and perform battery formation and solidification in sequence to obtain a lithium battery. This is beneficial to improving the battery performance.
[0035] Compared with the prior art, the present invention has the following beneficial effects:
[0036] 1. The present invention applies a chain transfer agent to the battery field, which can improve the problem of uneven molecular weight distribution of the polymer electrolyte. That is, a chain transfer agent is added to the in-situ solidified electrolyte to effectively control the polymerization reaction. The present invention further selects the composition of the chain transfer agent to obtain a polymer electrolyte with a more uniform molecular weight distribution, reduces the molecular weight of the prepared polymer electrolyte, and improves the ionic conductivity and cycle performance of the in-situ solidified electrolyte at room temperature.
[0037] 2. Since the chain transfer agent is extremely easy to hydrolyze in an acidic environment, and the acidity of the electrolyte will increase greatly during the high-temperature curing stage, the chain transfer agent is very unstable. However, the present invention adds a stabilizing additive to the in-situ solidified electrolyte to solve the problem of the unstable and easily decomposed chain transfer agent. The stabilizing additive can adjust the pH value during the high-temperature curing stage, control the electrolyte to be neutral, reduce the risk of instability and easy decomposition of the chain transfer agent due to the increase in acidity during the high-temperature curing stage, improve the stability of the chain transfer agent in the in-situ solidified electrolyte, and reduce the risk of the chain transfer agent being decomposed.
[0038] 3. The in-situ solidified electrolyte of the present invention can obtain a polymer electrolyte only by in-situ polymerization, is compatible with the existing process, has a low cost, and is beneficial to large-scale production and application. Brief Description of the Drawings
[0039] Combined with the drawings and referring to the following detailed description, the above and other features, advantages and aspects of the embodiments of the present disclosure will become more obvious. The drawings are used to better understand the solution and do not constitute a limitation to the present disclosure. In the drawings, the same or similar reference numerals represent the same or similar elements, where:
[0040] Figure 1 It is a comparison diagram of PDI between Examples 1-5 and Comparative Example 1 in the embodiments of the present invention.
[0041] Figure 2 It is the Mw max / Mw min comparison diagram between Examples 1-5 and Comparative Example 1 in the embodiments of the present invention.
[0042] Figure 3 It is a comparison diagram of conductivity between Examples 1-6 and Comparative Examples 1 and 2 in the embodiments of the present invention.
[0043] Figure 4 It is a comparison diagram of charge and discharge performance between Examples 1-6 and Comparative Examples 1 and 2 in the embodiments of the present invention. Detailed implementation manners
[0044] To make the objectives, technical solutions, and advantages of the embodiments of the present disclosure clearer, the technical solutions in the embodiments of the present disclosure will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present disclosure. Apparently, the described embodiments are some, but not all, of the embodiments of the present disclosure. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present disclosure without creative efforts shall fall within the protection scope of the present disclosure.
[0045] The present invention will be further described below in conjunction with embodiments.
[0046] Embodiment 1
[0047] This embodiment provides a method for preparing a polymer electrolyte, including the following steps:
[0048] S1: Prepare an in-situ curing electrolyte
[0049] Prepare an in-situ curing electrolyte according to the mass ratio of 2-cyano-2-propyl-4-cyanophenyl dithiocarbonate: methyl methacrylate: electrolyte: azobisisobutyronitrile = 0.025:5:95:0.05.
[0050] Among them, the electrolyte is a solution of 1 mol / L LiPF6 dissolved in a mixed solvent of EC, DMC, and EMC, and the volume ratio of EC, DMC, and EMC is 1:1:1.
[0051] S2: Cure the in-situ curing electrolyte obtained in S1 at a high temperature, and react at 60°C for 10 h to obtain a polymer electrolyte.
[0052] Embodiment 2
[0053] S1: Prepare an in-situ curing electrolyte
[0054] Prepare an in-situ curing electrolyte according to the mass ratio of 2-cyano-2-propyldodecyltrithiocarbonate: methyl methacrylate: electrolyte: azobisisobutyronitrile = 0.025∶5∶95:0.05.
[0055] Among them, the electrolyte is a solution of 1 mol / L LiPF6 dissolved in a mixed solvent of EC, DMC, and EMC, and the volume ratio of EC, DMC, and EMC is 1:1:1.
[0056] S2: Cure the in-situ curing electrolyte obtained in S1 at a high temperature, and react at 60°C for 10 h.
[0057] Embodiment 3
[0058] S1: Prepare an in-situ curing electrolyte
[0059] Prepare an in-situ curing electrolyte according to the mass ratio of 2-cyano-2-propyl dodecyl trithiocarbonate: tris(trimethylsilyl) phosphite: methyl methacrylate: electrolyte: azobisisobutyronitrile = 0.025: 0.025: 5: 95: 0.05.
[0060] Among them, the electrolyte is a solution of 1 m01 / L LiPF6 dissolved in a mixed solvent of EC, DMC, and EMC, and the volume ratio of EC, DMC, and EMC is 1:1:1.
[0061] S2: Cure the in-situ curing electrolyte obtained in S1 at a high temperature, and react at 60 °C for 10 h.
[0062] Example 4
[0063] S1: Prepare an in-situ curing electrolyte
[0064] Prepare an in-situ curing electrolyte according to the mass ratio of 2-cyano-2-propyl dodecyl trithiocarbonate: p-toluenesulfonyl isocyanate: methyl methacrylate: electrolyte: azobisisobutyronitrile = 0.025: 0.025: 5: 95: 0.05.
[0065] Among them, the electrolyte is a solution of 1 mo1 / L LiPF6 dissolved in a mixed solvent of EC, DMC, and EMC, and the volume ratio of EC, DMC, and EMC is 1:1∶1
[0066] S2: Cure the in-situ curing electrolyte obtained in S1 at a high temperature, and react at 60 °C for 10 h.
[0067] Example 5
[0068] S1: Prepare an in-situ curing electrolyte
[0069] Prepare an in-situ curing electrolyte according to the mass ratio of ethyl O-xanthate: dimethoxydimethylsilane: acrylonitrile: electrolyte: azobisisobutyronitrile = 0.025: 0.025: 5: 95: 0.05.
[0070] Among them, the electrolyte is a solution of 1mol / L LiPF6 dissolved in a mixed solvent of EC, DMC, and EMC, and the volume ratio of EC, DMC, and EMC is 1∶1∶1
[0071] S2: Cure the in-situ curing electrolyte obtained in S1 at a high temperature, and react at 60 °C for 10 h.
[0072] Example 6
[0073] S1: Prepare an in-situ curing electrolyte
[0074] Prepare an in-situ curing electrolyte according to the mass ratio of 2-cyano-2-propyl dodecyl trithiocarbonate: tris(trimethylsilyl) phosphite: polyethylene glycol dimethacrylate: lithium salt: azobisisobutyronitrile = 0.375: 0.375: 75: 25: 0.75. Among them, the lithium salt is LiPF6.
[0075] S2: Cure the in-situ curing electrolyte obtained in S1 at high temperature, and react at 60 °C for 10 h.
[0076] Comparative Example 1
[0077] S1: Prepare an in-situ curing electrolyte
[0078] Prepare an in-situ curing electrolyte according to the mass ratio of methyl methacrylate: electrolyte: azobisisobutyronitrile = 5: 95: 0.05.
[0079] Among them, the electrolyte is a solution of 1 mol / L LiPF6 dissolved in a mixed solvent of EC, DMC, and EMC, and the volume ratio of EC, DMC, and EMC is 1: 1: 1
[0080] S2: Cure the in-situ curing electrolyte obtained in S1 at high temperature, and react at 60 °C for 10 h.
[0081] Comparative Example 2
[0082] S1: Prepare an in-situ curing electrolyte
[0083] Prepare an in-situ curing electrolyte according to the mass ratio of polyethylene glycol dimethacrylate: lithium salt: azobisisobutyronitrile = 75: 25: 0.75. Among them, the lithium salt is LiPF6.
[0084] S2: Cure the in-situ curing electrolyte obtained in S1 at high temperature, and react at 60 °C for 10 h.
[0085] The polydispersity index (PDI), Mn, Mw, and the molecular weight range corresponding to the weight-average molecular weight of the polymer electrolytes prepared in Examples 1-5 and Comparative Example 1 were tested by GPC, and the results are shown in Table 1.
[0086] The test method is as follows: Place the polymer electrolyte system in a dialysis bag with a molecular weight of 1000, dialyze in deionized water for 12 h to wash away the lithium salt. Then dry it by heating at 60 °C for 12 h, and test the number-average molecular weight, weight-average molecular weight, and weight-average molecular weight distribution range with a gel permeation chromatograph.
[0087] Table 1
[0088] Mn Mw PDI Molecular weight range (weight average) <![CDATA[Mw max / Mw min > Example 1 65959 112593 1.71 11147-291830 26.18 Example 2 68495 104797 1.53 12152-237693 19.56 Example 3 59986 77382 1.29 10555-103122 9.77 Example 4 63258 85398 1.35 11487-174028 15.15 Example 5 61466 80520 1.31 10955-125873 11.49 Comparative Example 1 76762 147345 1.92 4846-573846 118.42
[0089] As shown in Table 1, the polymer electrolytes prepared in Examples 1-5 have a smaller average molecular weight and a smaller polydispersity index (PDI) compared to the one prepared in Comparative Example 1. The molecular weight range was measured, and the molecular weight distribution range of the polymer electrolytes prepared in Examples 1-5 is more concentrated.
[0090] The PDI of Examples 1-5 and Comparative Example 1 is presented in the form of a bar chart, and the results are as Figure 1 shown. The ratio of the maximum to the minimum weight-average molecular weight (Mw max / Mw min ) of Examples 1-5 and Comparative Example 1 is presented in the form of a bar chart, and the results are as Figure 2 shown.
[0091] It can be visually seen from Figure 1 and 2 that the molecular weight distribution of the polymer electrolytes prepared in Examples 1-5 is more uniform than that in Comparative Example 1.
[0092] Figure 2 As shown, the Mw max / Mw min of the polymer electrolyte in Example 1 is reduced by 4.52 times compared to the Mw max / Mw min of the polymer electrolyte in Comparative Example 1. The Mw max / Mw min of the polymer electrolyte in Example 2 is reduced by 6.05 times compared to the Mw max / Mw min of the polymer electrolyte in Comparative Example 1. The Mw max / Mw min of the polymer electrolyte in Example 3 is reduced by 12.12 times. The Mw max / Mw min of the polymer electrolyte in Example 4 is reduced by 7.82 times. The Mw max / Mw min of the polymer electrolyte in Example 5 is reduced to 10.31 compared to the Mw max / Mw min of the polymer electrolyte in Comparative Example 1. Thus, it can be further seen that the polymer provided in the examples has a relatively uniform molecular weight distribution and a more concentrated molecular weight distribution.
[0093] The polymer matrix of the polymer electrolytes prepared in Example 6 and Comparative Example 2 is a cross-linked polymer, and its molecular weight cannot be tested by GPC. However, in principle, it should have the same effect of improving polymerization uniformity. Therefore, the degree of improving polymerization uniformity is characterized by electrical property tests.
[0094] The button cells were assembled in the order of CR2032 type negative electrode case, polytetrafluoroethylene gasket, 90 μL in-situ solidified electrolyte, and CR2032 type positive electrode case, and cured at 60 °C for 10 h. Subsequently, the button cells prepared from the polymer electrolytes based on Examples 1-6 and Comparative Examples 1 and 2 were tested for AC impedance spectroscopy with a frequency range of 0.1 Hz - 1000000 Hz and an AC amplitude of 0.005 V. The results are as Figure 3 shown. As can be seen from Figure 3 the figure, the impedance of the polymer electrolytes prepared in Examples 1-5 is less than that of the polymer electrolyte prepared in Comparative Example 1, and the impedance of the polymer electrolyte prepared in Example 6 is less than that of the polymer electrolyte prepared in Comparative Example 2.
[0095] The button cells were assembled in the order of CR2032 type negative electrode case, graphite negative electrode, PE separator (diameter 16.2 mm, thickness 16 μm, coated with 4 μm alumina coating), 90 μL in-situ solidified electrolyte, NCM positive electrode, and CR2032 type positive electrode case, and cured at 60 °C for 10 h. Subsequently, the button cells prepared from the polymer electrolytes based on Examples 1-6 and Comparative Examples 1 and 2 were tested for constant current charge and discharge (2.5 - 4.25 V, activated at 0.1C for 2 cycles, and then cycled at 0.3C). The results are as Figure 4 shown. As can be seen from Figure 3 the figure, the charge and discharge performance of the polymer electrolytes prepared in Examples 1-6 is better than that of the polymer electrolytes prepared in Comparative Examples 1 and 2.
[0096] It should be noted that for the foregoing method embodiments, for the sake of simple description, they are all expressed as a series of action combinations. However, those skilled in the art should know that the present disclosure is not limited by the described action sequence, because according to the present disclosure, certain steps can be performed in other sequences or simultaneously. Secondly, those skilled in the art should also know that the embodiments described in the specification are all optional embodiments, and the actions and modules involved are not necessarily essential to the present disclosure.
[0097] Those skilled in the art can clearly understand that for the convenience and brevity of description, the specific working process of the described modules can refer to the corresponding process in the foregoing method embodiments, and will not be repeated here.
[0098] It should be understood that various forms of the processes shown above can be used, reordering, adding, or deleting steps. For example, the steps described in the present disclosure can be executed in parallel, sequentially, or in different orders, as long as the desired results of the technical solutions of the present disclosure can be achieved. No limitation is imposed herein.
[0099] The above specific embodiments do not constitute a limitation on the protection scope of the present disclosure. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principle of the present disclosure shall be included within the protection scope of the present disclosure.
Claims
1. An in-situ solidifying electrolyte, comprising: A chain transfer agent, a stabilizing additive, a reactive monomer, an initiator, and an electrolyte solution.
2. The in-situ solidified electrolyte according to claim 1, characterized in that, The chain transfer agent is a compound containing a -C(=S)S- or -SC(=S)S- structure.
3. The in-situ solidified electrolyte according to claim 2, wherein The chain transfer agent includes one or more of polythiocarbonate chain transfer agents, thioester chain transfer agents, xanthate chain transfer agents, and polythiocarbamate chain transfer agents.
4. The in-situ curing electrolyte solution according to claim 3, wherein the chain transfer agent is further selected from one or more of dithiocarbonate chain transfer agents, trithiocarbonate chain transfer agents, xanthate chain transfer agents, and dithiocarbamate chain transfer agents; Preferably, the chain transfer agent is selected from one or more of 2-cyano-2-propyl dodecyl trithiocarbonate, 2-cyano-2-propyl-4-cyanophenyl dithiocarbonate, 2-phenylpropyl thioester of thiobenzoic acid, 2-cyano-2-propyl benzodithio, 4-cyano-4-(thiobenzoylthio)valeric acid, S,S-dibenzyl trithiocarbonate, O-ethyl ethyl xanthate, and dithiocarbamate.
5. The in-situ curing electrolyte solution according to claim 1, characterized in that The stabilizing additive is selected from acid-removing additives; Preferably, the stabilizing additive is selected from hydrofluoric acid-removing additives; Preferably, the stabilizing additive includes one or more of isocyanate compounds, siloxane compounds, silane compounds, phosphite compounds, and amine compounds; Preferably, the stabilizing additive includes one or more of p-toluenesulfonyl isocyanate, trimethylsilyl isocyanate, phenyl isocyanate, hexamethylene diisocyanate, toluene diisocyanate, trimethylsilyl isothiocyanate, aminoalkyl disiloxane, tris(trimethylsilyl) phosphate, methyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, tris(trimethylsilyl) phosphite, trimethyl phosphite, triethyl phosphite, triphenyl phosphite, phthalic anhydride, succinic anhydride, and ethanolamine.
6. The in-situ solidified electrolyte according to claim 1, wherein The reactive monomer includes at least one of vinyl monomers having a carbonyl group, aromatic ring vinyl monomers, alkyl vinyl monomers, or vinyl monomers having a lone pair of electrons connecting oxygen / nitrogen; Preferably, the reactive monomer includes one or more of acrylate monomers, amide monomers, benzene vinyl monomers and their copolymers, acrylonitrile monomers, vinyl ester monomers, and vinyl pyridine monomers.
7. The in-situ solidified electrolyte according to claim 1, characterized in that, The chain transfer agent accounts for 0.01% - 1% by mass of the in-situ curing electrolyte solution; preferably 0.01 - 0.2%; And / or, the stabilizing additive accounts for 0.01% - 1% by mass of the in-situ curing electrolyte solution; preferably 0.01 - 0.2%; And / or, the reactive monomer accounts for 5% - 90% by mass of the in-situ curing electrolyte solution; And / or, the electrolyte solution accounts for 0% - 95% by mass of the in-situ curing electrolyte solution; And / or, the initiator accounts for 0.2% - 2% by mass of the reactive monomer.
8. Use of the in-situ curing electrolyte solution according to any one of claims 1 - 7 in the preparation of a polymer electrolyte.
9. A polymer electrolyte, characterized in that, One end of the polymer electrolyte chain contains a dithio functional group and a trithio functional group.
10. The polymer electrolyte according to claim 9, characterized in that, The polymer electrolyte is a linear polymer, a cross-linked polymer or a graft polymer.
11. The polymer electrolyte according to claim 9, characterized in that, The ratio of the maximum weight average molecular weight to the minimum weight average molecular weight of the polymer electrolyte is 1-30; And / or, the molecular weight distribution of the polymer electrolyte, the polydispersity index is 1-1.8, preferably 1-1.
4.
12. Use of the in-situ curing electrolyte according to any one of claims 1-7 or the polymer electrolyte according to any one of claims 9-11 in a battery.
13. A battery, characterized in that, Comprising the in-situ curing electrolyte according to any one of claims 1-7 or the polymer electrolyte according to any one of claims 9-11.
14. A method for preparing a battery, characterized in that, Comprising the following steps: Prepare the in-situ curing electrolyte according to any one of claims 1-7; Inject the in-situ curing electrolyte according to any one of claims 1-7 into the battery, and successively perform battery formation and curing to obtain the battery.