Hydrogenated nitrile rubber composite solid electrolyte as well as preparation method and application thereof
By using hydrogenated nitrile rubber composite solid electrolyte, the problems of low ionic conductivity and poor lithium interface stability of the existing HNBR/LiTFSI solid electrolyte are solved, and higher ionic conductivity and longer battery life are achieved.
Patent Information
- Application Number
- CN202510390705.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-31
- Publication Date
- 2025-06-20
AI Technical Summary
The existing HNBR/LiTFSI solid electrolyte has low ionic conductivity and poor lithium interface stability, resulting in a short battery life.
The hydrogenated nitrile rubber composite solid electrolyte is made of hydrogenated nitrile rubber, polyethylene oxide, lithium salt and inorganic filler, and is prepared by solution casting method, which increases the ionic conductivity and oxidation stability of the composite solid electrolyte.
It improves the ionic conductivity of solid electrolytes, improves the stability of lithium interface, extends the service life of lithium metal batteries, and maintains good electrochemical stability at high voltages.
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Figure CN120184344A_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to the field of solid electrolytes, and particularly relates to a hydrogenated nitrile rubber composite solid electrolyte, a preparation method thereof, and an application thereof. Background Art
[0002] Lithium-ion batteries have safety problems such as easy leakage, easy volatilization, flammability, explosiveness, and poor thermal stability, which limit their development. Solid-state lithium-ion batteries using solid electrolytes to replace liquid electrolytes are expected to fundamentally solve the safety problems of batteries. Solid electrolytes are generally divided into three categories: inorganic solid electrolytes, polymer solid electrolytes, and composite solid electrolytes. Among them, inorganic solid electrolytes have characteristics such as high room-temperature ionic conductivity, wide electrochemical window, and high mechanical strength, but they are brittle and have a large solid-solid contact resistance. Polymer solid electrolytes usually have good flexibility, processing performance, and good interfacial contact, but have a low ionic conductivity and relatively poor mechanical strength. Composite solid electrolytes combine the advantages of inorganic solid electrolytes and polymer solid electrolytes, and not only have better ionic conductivity but also excellent mechanical properties.
[0003] The nitrile-based electrolyte system has become an important candidate material for high-voltage solid-state batteries due to its excellent oxidation stability and strong lithium-ion coordination ability. Hydrogenated nitrile rubber (HNBR) is prepared by catalytic hydrogenation of nitrile rubber (NBR) with a metal catalyst and is widely used in applications that require higher oxidation and thermal stability. HNBR has new application explorations in the lithium battery field, such as being used as a battery binder, dispersant, solid electrolyte, etc., which provides new possibilities for the development of the new energy field. Although the HNBR / LiTFSI solid electrolyte has an oxidation stability of more than 5 V, its ionic conductivity is 7.2×10 -6 S / cm at 70 °C, and the HNBR / LiTFSI solid electrolyte has poor lithium interface stability and short circuits after 146 h, with an overpotential of about 0.3 V (ACS Applied Energy Materials, 2019, 2(5): 3264-3273). By introducing a phthalate - diethyl phthalate (DEP) plasticizer, the mobility of polymer segments can be increased and the glass transition temperature can be reduced, and the oxidation stability of the HNBR / LiTFSI solid electrolyte will not be reduced. The ionic conductivity is 4.4×10 -5 S / cm at 70 °C, and the lithium interface stability is improved. Short circuit occurs after 413 h, and at this time the overpotential increases to 0.18 V (ACS Applied Polymer Materials, 2019, 2(1): 80-90). Therefore, there is an urgent need to develop a high-performance HNBR-based solid electrolyte with high ionic conductivity, wide electrochemical window, and good interfacial compatibility. Summary of the Invention
[0004] To solve the problems in the background art, the present invention provides a hydrogenated nitrile rubber composite solid electrolyte and a preparation method thereof. The composite solid electrolyte membrane can effectively improve the interfacial contact between the solid electrolyte and the positive and negative electrodes, reduce the interfacial impedance, and has good ionic conductivity and oxidation stability.
[0005] The object of the present invention is to provide an HNBR composite solid electrolyte with good ion transport ability and strong stability.
[0006] The present invention adopts the following technical solutions: The present invention provides a hydrogenated nitrile rubber composite solid electrolyte, which is composed of hydrogenated nitrile rubber, polyethylene oxide, lithium salt and inorganic filler, and is prepared by a solution casting method.
[0007] Further, the raw materials of the hydrogenated nitrile rubber composite solid electrolyte include, by weight: 100-200 parts of hydrogenated nitrile rubber, 3-10 parts of polyethylene oxide, 20-100 parts of lithium salt, and 10-60 parts of inorganic filler.
[0008] The present invention provides a preparation method of a hydrogenated nitrile rubber composite solid electrolyte. The preparation steps are as follows: Weigh 20-100 parts of lithium salt in proportion, add 2000-4000 parts of solvent, and magnetically stir at 40-65 o °C for 2-4 hours. Add 10-60 parts of inorganic filler in proportion and magnetically stir for 6-12 hours. Add 100-200 parts of hydrogenated nitrile rubber and 3-10 parts of polyethylene oxide in proportion, and continue to heat and magnetically stir for 18-36 hours. Cast into a film and dry in a vacuum oven at 50-80 o °C for 48-72 h.
[0009] The hydrogenated nitrile rubber is prepared by catalytic hydrogenation of nitrile rubber with a metal catalyst. The reaction is carried out in a hydrogenation reactor: dissolve nitrile rubber in one or more of acetone, cyclohexanone, and dichloromethane, add Pd / C catalyst, and react at 40-90 °C, hydrogen pressure of 1-4 MPa, and stirring speed of 400-800 rpm for 0.5-6 h. Then, flocculate the product with deionized water to obtain hydrogenated nitrile rubber.
[0010] The prepared hydrogenated nitrile rubber has a nitrile group content of 33%-44 wt%, a molecular weight of 100,000-400,000, and a hydrogenation degree of 80%-97%.
[0011] The lithium salt is one or more of lithium bis(trifluoromethanesulfonyl)imide, lithium bis(fluorosulfonyl)imide, and lithium perchlorate.
[0012] The inorganic filler is one or more of TiO2, SiO2, lithium lanthanum zirconium oxide (LLZO), and lithium lanthanum zirconium tantalum oxide (LLZTO); The molecular weight of the polyethylene oxide is 300,000 - 5,000,000; The solvent is one or more of N, N-dimethylformamide, toluene, tetrahydrofuran, dichloromethane, and dimethyl sulfoxide; The thickness of the hydrogenated nitrile butadiene rubber composite solid electrolyte membrane is 160 - 220 µm.
[0013] The present invention provides a hydrogenated nitrile butadiene rubber composite solid electrolyte for lithium ion batteries.
[0014] Compared with the prior art, the present invention has achieved the following beneficial effects: (1) By testing the electrochemical properties of different HNBR composite solid electrolytes, the hydrogenated nitrile butadiene rubber with high nitrile content, high molecular weight, and high hydrogenation degree in the present invention has the best performance, and the ionic conductivity is 3.4×10 o S / cm at 70 -4 °C.
[0015] (2) By adding polyethylene oxide and inorganic filler to the HNBR solid electrolyte, the compatibility between the composite solid electrolyte and the lithium metal negative electrode can be improved, the ion transport ability can be enhanced, and the service life of the solid lithium metal battery can be prolonged. Description of the Drawings
[0016] Figure 1 It is the electrochemical window of the solid electrolytes of Example 1, Example 2, Example 3, and Comparative Example 1.
[0017] Figure 2 It is the test chart of the critical current density of the lithium symmetric batteries of Example 1 and Comparative Example 1. Detailed Embodiments
[0018] To facilitate the understanding of the present invention, the following will describe the present invention more comprehensively and meticulously in conjunction with the drawings of the specification and preferred embodiments. However, the protection scope of the present invention is not limited to the following specific embodiments. Unless otherwise defined, all the professional terms used hereinafter have the same meaning as commonly understood by those skilled in the art.
[0019] Example 1 In the HNBR composite solid electrolyte of this example, the nitrile group content of HNBR is 41 wt%, the molecular weight is 360,000, and it is prepared by catalytic hydrogenation of nitrile butadiene rubber in a hydrogenation reaction kettle with a metal catalyst, and the hydrogenation degree is 97%. The molecular weight of polyethylene oxide PEO is 600,000.
[0020] The specific preparation method of the composite solid electrolyte with a thickness of 180 µm is as follows: Weigh lithium bis(trifluoromethanesulfonyl)imide in proportion, add N, N-dimethylformamide, and stir magnetically at 45 o °C for 2 hours. Add lithium lanthanum zirconium tantalum oxide (LLZTO) in proportion and stir magnetically for 12 hours. Then add the above hydrogenated nitrile rubber and polyethylene oxide in proportion, continue heating and stirring magnetically for 24 hours, cast into a film, and dry in a vacuum oven at 60 o °C until the solvent evaporates. Among them, there are 100 parts of hydrogenated nitrile rubber, 3 parts of polyethylene oxide, 45 parts of lithium bis(trifluoromethanesulfonyl)imide, 20 parts of lithium lanthanum zirconium tantalum oxide, and 2000 parts of N, N-dimethylformamide.
[0021] Example 2 It is basically the same as Example 1, except that: there are 100 parts of hydrogenated nitrile rubber, 3 parts of polyethylene oxide, 45 parts of lithium bis(trifluoromethanesulfonyl)imide, and 10 parts of lithium lanthanum zirconium tantalum oxide.
[0022] Example 3 It is basically the same as Example 1, except that: there are 100 parts of hydrogenated nitrile rubber, 3 parts of polyethylene oxide, 45 parts of lithium bis(trifluoromethanesulfonyl)imide, and 30 parts of lithium lanthanum zirconium tantalum oxide.
[0023] Example 4 It is basically the same as Example 1, except that: the hydrogenated nitrile rubber with a nitrile group content of 41 wt%, a molecular weight of 36W, and a hydrogenation degree of 97% is replaced with a hydrogenated nitrile rubber with a nitrile group content of 41 wt%, a molecular weight of 36W, and a hydrogenation degree of 90%.
[0024] Example 5 It is basically the same as Example 1, except that: the hydrogenated nitrile rubber with a nitrile group content of 41 wt%, a molecular weight of 36W, and a hydrogenation degree of 97% is replaced with a hydrogenated nitrile rubber with a nitrile group content of 41 wt%, a molecular weight of 36W, and a hydrogenation degree of 80%.
[0025] Example 6 It is basically the same as Example 1, except that: the hydrogenated nitrile rubber with a nitrile group content of 41 wt%, a molecular weight of 36W, and a hydrogenation degree of 97% is replaced with a hydrogenated nitrile rubber with a nitrile group content of 35 wt%, a molecular weight of 36W, and a hydrogenation degree of 97%.
[0026] Example 7 It is basically the same as Example 1, except that: the hydrogenated nitrile rubber with a nitrile group content of 41 wt%, a molecular weight of 36W, and a hydrogenation degree of 97% is replaced with a hydrogenated nitrile rubber with a nitrile group content of 35 wt%, a molecular weight of 10W, and a hydrogenation degree of 97%.
[0027] Comparative Example 1 It is basically the same as Example 1, except that: PEO and LLZTO are not added, and a solid electrolyte is obtained.
[0028] Comparative Example 2 It is basically the same as Example 1, except that: LLZTO is not added, and a solid electrolyte is obtained.
[0029] Comparative Example 3 It is basically the same as Example 1, except that: PEO is not added, and a solid electrolyte is obtained.
[0030] Comparative Example 4 It is basically the same as Example 1, except that: the hydrogenated nitrile rubber with a hydrogenation degree of 97% is replaced with non-hydrogenated nitrile rubber.
[0031] Application Example The solid electrolytes prepared in Examples 1-7 and Comparative Examples 1-4 are assembled into button cells, and their electrochemical properties are measured.
[0032] The prepared solid electrolyte is assembled into a symmetric cell (SS|composite electrolyte membrane|SS, where SS is a stainless steel sheet). The ionic conductivity is measured by electrochemical impedance spectroscopy. The test temperature ranges from 25 °C to 100 °C, and the test is carried out every 15 °C. The frequency ranges from low frequency 0.01 Hz to high frequency 10 6 Hz, and the AC amplitude is 10 mV. The ionic conductivities of the composite solid electrolytes in Examples 1-7 and Comparative Examples 1-4 are shown in Table 1.
[0033] Table 1 Ionic conductivities of the composite solid electrolytes in Examples 1-7 and Comparative Examples 1-4 (10 -5 S / cm)
[0034] It can be seen from the data in Table 1 that for the composite solid electrolyte, as the hydrogenation degree, nitrile group content, and molecular weight increase, the ionic conductivity also increases. The composite solid electrolyte in Example 1 has the best performance. At 70 °C, the ionic conductivity is 3.4×10 -4 S / cm. Compared with Comparative Examples 1-3, it shows that the addition of appropriate amounts of PEO and LLZTO is beneficial to the improvement of ionic conductivity.
[0035] The linear sweep voltammetry (LSV) is used to test the electrochemical stability window of the electrolyte. After assembling a battery in the order of stainless steel sheet, electrolyte, and lithium sheet, it is tested at a speed of 2 mV S -1 within 2.5 - 6 V until the voltage plateau of the electrolyte material changes, so as to judge the high-voltage stable potential of the electrolyte membrane. The voltage window of the composite solid electrolyte is shown inFigure 1 As shown in the figure, the high-voltage stable potential of the composite solid electrolyte in Example 1 reached 5.1 V, which means that this electrolyte can match the cathode materials with high voltage and can be used in high-voltage all-solid-state lithium-ion batteries. The high-voltage stable potential of the composite solid electrolyte in Example 3 was 5 V, showing a certain degree of decrease in the electrochemical window compared with that in Example 1. This is because the excessive LLZTO nanoparticles agglomerated in the HNBR matrix, resulting in the easier oxidation and decomposition of the composite solid electrolyte.
[0036] The composite films of Example 1 and Comparative Example 1 prepared were respectively assembled into Li / solid electrolyte / Li symmetric batteries, and their stability tests were carried out under a certain current density and a heat preservation environment of 65 °C. The results are as Figure 2 shown. At a current density of 0.1 mA / cm 2 , the overpotential of the solid electrolyte in Comparative Example 1 was 0.04 V, and there was no obvious fluctuation after cycling for 100 h. However, with the extension of time, the overpotential became larger and larger, indicating that the stability of the solid electrolyte at the lithium interface was poor. While the overpotential of Example 1 was 0.031 V, and there was no obvious fluctuation after cycling for 500 h. This shows that the addition of PEO and LLZTO particles can improve the compatibility between the composite solid electrolyte and the lithium metal anode, and extend the service life of the all-solid-state lithium metal battery.
[0037] The above is only the specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention.
Claims
1. A hydrogenated nitrile rubber composite solid electrolyte, characterized in that: The raw materials of the hydrogenated nitrile rubber composite solid electrolyte include, by weight: 100-200 parts of hydrogenated nitrile rubber, 3-10 parts of polyethylene oxide, 20-100 parts of lithium salt, and 10-60 parts of inorganic filler.
2. The hydrogenated nitrile rubber composite solid electrolyte according to claim 1, characterized in that: The molecular weight of the polyethylene oxide is 300,000-5,000,000.
3. The hydrogenated nitrile rubber composite solid electrolyte according to claim 1, characterized in that: The lithium salt is one or more of lithium bis(trifluoromethanesulfonyl)imide, lithium bis(fluorosulfonyl)imide and lithium perchlorate.
4. The hydrogenated nitrile rubber composite solid electrolyte according to claim 1, characterized in that: The inorganic filler is one or more of TiO2, SiO2, lithium lanthanum zirconium oxide, and lithium lanthanum zirconium tantalum oxide.
5. The hydrogenated nitrile rubber composite solid electrolyte according to claim 1, characterized in that: The hydrogenated nitrile rubber is prepared by hydrogenating nitrile rubber with a metal catalyst. The reaction is carried out in a hydrogenation reactor, specifically comprising: dissolving the nitrile rubber in one or more of acetone, cyclohexanone and dichloromethane, adding a Pd / C catalyst, reacting for 0.5-6 h at 40-90° C., a hydrogen pressure of 1-4 MPa and a stirring speed of 400-800 rpm, and then flocculating the product with deionized water to obtain the hydrogenated nitrile rubber.
6. The hydrogenated nitrile rubber according to claim 1, wherein The hydrogenated nitrile rubber has a nitrile group content of 33-44 wt %, a molecular weight of 100000-400000, and a degree of hydrogenation of 80%-97%.
7. A method for preparing a hydrogenated nitrile rubber composite solid electrolyte according to any one of claims 1 to 6, characterized in that: The following steps are involved: Weigh 20-100 parts of lithium salt by weight, add 2000-4000 parts of solvent, and heat at 40-65 oC Stir under magnetic force for 2-4 hours, add 10-60 parts of inorganic filler, stir under magnetic force for 6-12 hours, add 100-200 parts of hydrogenated nitrile rubber and 3-10 parts of polyethylene oxide, continue heating and stirring under magnetic force for 18-36 hours, cast into film, and place in vacuum oven at 50-80 o C and dried for 48-72h to obtain a hydrogenated nitrile rubber composite solid electrolyte.
8. The method for preparing the hydrogenated nitrile rubber composite solid electrolyte according to claim 7, characterized in that: The solvent is one or more of N, N-dimethylformamide, toluene, tetrahydrofuran, dichloromethane, and dimethyl sulfoxide.
9. The method for preparing the hydrogenated nitrile rubber composite solid electrolyte according to claim 7, characterized in that: The thickness of the hydrogenated nitrile rubber composite solid electrolyte is 160-220 µm.
10. An application of the hydrogenated nitrile rubber composite solid electrolyte according to any one of claims 1 to 6, characterized in that: For lithium-ion batteries.