CN109786869B - Application of polymer containing hindered amine structure in secondary lithium battery - Google Patents

Abstract

The invention relates to the application of a polymer containing a hindered amine structure in a secondary lithium battery. The polymer contains hindered amine structural units, which can capture oxygen radical species generated during battery operation, quench hydroperoxides, capture heavy metals, and quench singlet oxygen generated during battery operation, so it is beneficial to suppress side effects at the positive electrode interface. Reaction, reducing oxygen-containing exhaust gas, improving the Coulombic efficiency and long-term cycle performance of the battery.

Description

Application of a polymer containing hindered amine structure in secondary lithium battery

technical field

The invention relates to the field of secondary lithium batteries, in particular to the application of a polymer containing hindered amine structure in secondary lithium batteries.

Background technique

Due to the advantages of high energy density and good reliability, lithium-ion batteries have achieved great development in mobile devices, electric vehicles, smart grids and other fields. However, the recent serious battery burning accidents in Tesla Model S cars (the battery pack uses NCA as the positive electrode active material) have sounded the alarm for the commercial application of lithium batteries. According to literature reports, in the case of no obvious short circuit in the battery, the thermal runaway of the battery is closely related to the chemical shuttling of oxygen (especially singlet oxygen) generated by the cathode material (Joule 2018, DOI: 10.1016/j.joule.2018.06.015) . Specifically, the highly active singlet oxygen produced by the positive electrode material not only leads to the decomposition of the electrolyte, but also diffuses to the negative electrode interface to cause violent side reactions and release a large amount of heat, thus inducing the thermal runaway of the battery.

In order to avoid the risk of battery thermal runaway, scientists have made many beneficial attempts in the development of flame-retardant electrolytes and the research of new solid-state polymer electrolytes. For example, Cao Yuliang's research group at Wuhan University recently developed a non-combustible electrolyte system triethyl phosphate/LiFSI (molar ratio=2:1). The 18650 pouch battery assembled with this system not only exhibited high coulombic efficiency (99.7%) and stable cycle performance (90% capacity retention after 50 cycles), but also passed needle punching, short circuit, and heavy impact. and other safety tests, showing excellent safety performance (Nature Energy2018, DOI: 10.1038/s41560-018-0196-y); our research group prepared solid-state Polymer electrolyte, the assembled LiCoO ₂ /Li button cell not only exhibits superior rate performance and stable cycle performance (Adv. Sci. 2017, 4, 1600377), but also exhibits excellent safety. Although these methods can effectively improve the electrochemical and safety performance of batteries, the severe side reactions caused by highly active oxygen species at the positive electrode interface and the risk of thermal runaway induced by them have not been fundamentally suppressed or resolved. In view of the urgent need for high-safety and high-energy-density lithium batteries, developing a solution to effectively reduce the side reactions induced by reactive oxygen species is of great significance for the commercial application of high-safety and high-energy-density lithium batteries.

To sum up, how to avoid the thermal runaway problem of lithium-ion batteries has become one of the research hotspots in the scientific community. According to literature reports, severe side reactions and large heat release caused by active oxygen species are one of the causes of battery thermal runaway. Although scientists have made many active explorations in avoiding battery thermal runaway, the severe side reactions caused by highly active oxygen species at the positive electrode interface have not been fundamentally suppressed or resolved. Therefore, the development of a material system (polymer electrolyte or cathode coating) that can effectively suppress the side reactions caused by reactive oxygen species is of great significance for the commercial application of secondary lithium batteries.

Contents of the invention

The object of the present invention is to provide an application of a polymer containing hindered amine structure in a secondary lithium battery.

In order to achieve the above object, the technical solution adopted by the present invention is: to provide an application of a polymer containing hindered amine structure in a secondary lithium battery, and the polymer structure contains hindered amine structural units.

The application of a polymer containing a hindered amine structure in a secondary lithium battery, the polymer containing a hindered amine structure can capture oxygen free radical species generated during battery operation, quench hydroperoxides, capture heavy metals and Quenching the singlet oxygen generated during battery operation is beneficial to suppress side reactions at the positive electrode interface, reduce oxygen-containing waste gas, and improve the coulombic efficiency and cycle performance of the battery.

The application of a polymer containing a hindered amine structure in a secondary lithium battery, the structure of the polymer is shown in general formula 1:

(a的取值为1～250)，

(b的取值为1～250)，

(c的取值为1～250)，

(B的取值为NH，O，OCH₂；E^-的取值为PF₆ˉ，BF₄ˉ，TFSIˉ，FSIˉ，CH₃OSO₃ˉ)，

(B的取值为NH，O，OCH₂)，

(v的取值为1-4)；B取自O，NH，OCH₂；W的取值为0～4；X取自H，氧自由基，十八碳以下的烷氧基，十八碳以下的烷基，十八碳以下的酰基；Y取自H，甲基，甲氧基，CN，F；Z取自H，甲基，三氟甲基，氯甲基，氰基甲基。Among them, the value of m is 0-2000, and the value of n is 1-2000; A ₁ and A ₂ are respectively independently selected from H, COOH, CN, CONH ₂ , alkoxycarbonyl groups below octadecyl carbon, octadecyl Perfluoroalkoxycarbonyl with less than 18 carbons, alkylaminoacyl with less than 18 carbons, alkyl with less than 18 carbons, alkoxy with less than 18 carbons, aryl with less than 18 carbons,

(the value of a is 1~250),

(The value of b is 1~250),

(The value of c is 1~250),

(The value of B is NH, O, OCH ₂ ; the value of E ^- is PF ₆ ˉ, BF ₄ ˉ, TFSI ˉ, FSI ˉ, CH ₃ OSO ₃ ˉ),

(The value of B is NH, O, OCH ₂ ),

(The value of v is 1-4); B is taken from O, NH, OCH ₂ ; the value of W is 0-4; X is taken from H, oxygen radical, alkoxy group below octadecyl carbon, octadecyl Alkyl group with less than 10 carbons, acyl group with less than 18 carbons; Y is derived from H, methyl, methoxy, CN, F; Z is derived from H, methyl, trifluoromethyl, chloromethyl, cyanomethyl .

The application of a polymer containing a hindered amine structure in a secondary lithium battery, the lithium battery includes a negative electrode, a positive electrode, a separator placed between the negative electrode and the positive electrode, and a non-aqueous electrolyte; wherein the positive electrode includes a positive electrode Active material, binder, conductive carbon material and current collector; the positive electrode surface of the lithium battery is coated with the polymer or the non-aqueous electrolyte contains the polymer or the positive electrode binder contains the polymer.

The active material of the negative electrode is lithium metal, lithium metal alloy, graphite, hard carbon, molybdenum disulfide, lithium titanate, carbon-silicon composite material, carbon-germanium composite material, carbon-tin composite material, antimony oxide, antimony-carbon composite material, One or more of tin-antimony composite materials, lithium titanium oxide, and lithium metal nitride.

The active material of the positive electrode is lithium cobalt oxide, lithium manganese iron phosphate, lithium manganate, lithium nickel manganese oxide, lithium-rich manganese base, ternary material, lithium ion fluorophosphate, lithium vanadium fluorophosphate, lithium iron fluorophosphate One or more of salt, lithium manganese oxide; the binder of the positive electrode contains one or more of the polymer, wherein the polymer accounts for 0.001% to 20% of the positive electrode material

The diaphragm material is cellulose non-woven film, seaweed fiber non-woven film, aramid non-woven film, polyarylsulfonamide non-woven film, polypropylene non-woven film, glass fiber, polyethylene terephthalate film , One of the polyimide non-woven membranes.

The non-aqueous electrolyte includes lithium salt, organic matrix, and inorganic lithium ion conductor, wherein the polymer accounts for 0% to 60% of the total weight of the non-aqueous electrolyte.

The lithium salt is lithium hexafluorophosphate (LiPF ₆ ), lithium perchlorate (LiClO ₄ ), lithium bisoxalate borate (LiBOB), lithium difluorooxalate borate (LiDFOB), lithium trifluoromethanesulfonate (CF ₃ SO ₃ Li ), lithium bistrifluoromethylsulfonimide (LiTFSI), and lithium bisfluorosulfonimide (LiFSI), wherein the lithium salt accounts for 0% to 40% of the non-aqueous electrolyte.

The organic matrix is ethylene carbonate, dimethyl carbonate, ethyl methyl carbonate, propylene carbonate, diethyl carbonate, succinonitrile, ethanedinitrile, fluoroethylene carbonate, tetraethylene glycol dimethyl ether , Sulfolane, Polyvinylene Carbonate, Polyacrylonitrile, Polymethacrylate, Polyethylene Oxide, Polyethylene Carbonate, Polypropylene Carbonate, etc., the organic matrix accounts for 0% of the total weight of the electrolyte ~70%.

The inorganic lithium ion conductors are Li _3a La _(2/3)-a TiO ₃ (0.04<a<0.14), Li _3+a X _a Y _1-a O ₄ (X=Si, Sc, Ge, Ti ; Y=P, As, V, Cr, 0<a<1), LiZr ₂ (PO ₄ ) ₃ , Li ₇ La ₃ Zr ₂ O ₁₂ , Li _1+a Al _a Ti _2-a (PO ₄ ) ₃ (0<a<2), Li _1+a Al _a Ge _2-a (PO ₄ ) ₃ (0<a<2), Li ₃ OCl, Li ₃ OCl _0.5 Br _0.5 , Li ₁₀ GeP ₂ S ₁₂ , Li ₁₄ Zn(GeO ₄ ) ₄ , Li ₅ La ₃ M ₂ O ₁₂ (M=Ta, Nb), Li _5.5 La ₃ Nb _1.75 In _0.25 O ₁₂ , Li ₃ N-LiX (X=Cl, Br, I), Li _9-na M _a N ₂ Cl ₃ (M=Na, K, Rb, Cs, Mg, Al, 0<a<9, 0<n<4), 3Li ₃ N-MI (X=Li, Na, K), LiPON, Li ₂ SM _a S _b (M=Al, Si, P, 0<a<3, 0<b<6), Li ₆ PS ₅ X (X=F, Cl, Br, I) One or more, inorganic lithium ion conductors account for 0% to 99.9% of the total mass of the electrolyte.

The application of a polymer that prevents thermal runaway in a secondary lithium metal battery, the positive electrode coated with the polymer is prepared by the following method: the polymer is dissolved in a solvent to form a uniform solution, and the polymer containing the The solution is spin-coated on the surface of the positive electrode, and then dried in a vacuum oven at 80 degrees to obtain a positive electrode with a polymer coating, wherein the thickness of the coating is 0.001-50 μm.

The solution containing the polymer, the solvent for dissolving the polymer is dichloromethane, chloroform, 1,4-dioxane, ethylene glycol dimethyl ether, acetone, acetonitrile, dimethyl sulfoxide, sulfolane, sulfurous acid Dimethyl ester, diethyl sulfite, tetrahydrofuran, 1,2-dichloroethane, ethyl acetate, N-methylpyrrolidone, N,N-dimethylformamide and N,N-dimethylacetamide One or more of them, the polymer accounts for 10%-80% of the total weight of the solution.

The invention relates to the application of a polymer containing a hindered amine structure in a secondary lithium battery, which has the following advantages:

1. The polymer itself contains more lithium ion conductive groups and has higher lithium ion conductivity;

2. The polymer contains a hindered amine structure, which can capture oxygen free radical species generated during battery operation, quench hydroperoxide, capture heavy metals, and quench singlet oxygen generated during battery operation, so it is beneficial to suppress the side effects of the positive electrode interface. Reaction, reducing oxygen-containing exhaust gas, improving the Coulombic efficiency and cycle performance of the battery.

The technical scheme of the invention is easy to operate, has strong innovation and important application value. The scheme can be applied to high-voltage lithium batteries, solid-state lithium batteries (including lithium-sulfur batteries), and other secondary high-energy lithium batteries.

Description of drawings

The long-term cycle performance of the battery assembled in Fig. 1 Example 1 at room temperature at 1.0C.

The long-term cycle performance of the battery assembled in Fig. 2 Example 2 at 1.0C at room temperature.

Fig. 3 The long-term cycle performance of the battery assembled in Example 3 at room temperature at 0.2C.

Fig. 4 The long-term cycle performance of the battery assembled in Example 4 at room temperature at 0.5C.

Fig. 5 Long-term cycle performance at 0.5C at room temperature of the battery assembled in Example 5.

Fig. 6 Long cycle performance at 0.5C at room temperature of the battery assembled in Example 6.

Fig. 7 The long-term cycle performance of the battery assembled in Example 7 at room temperature at 0.5C.

Fig. 8 Long-term cycle performance at 0.1C at room temperature of the battery assembled in Example 8.

Fig. 9 Long cycle performance at room temperature of 0.1C of the battery assembled in Example 9.

Figure 10 is the long-term cycle performance at 0.5C at room temperature of the battery assembled in Example 10.

Fig. 11 Oxygen output of the battery assembled in Example 11 at room temperature in the first cycle at 0.5C.

Fig. 12 The carbon dioxide output of the battery assembled in Example 12 at 60 degrees Celsius in the first cycle of 1C cycle.

Fig. 13 The carbon monoxide output of the battery assembled in Example 13 at room temperature in the first cycle of 1C.

Figure 14 The long-term cycle performance of the battery assembled in Example 15 at 60°C at 2C.

detailed description

Example 1

(n＝80)的氯仿溶液(25wt％)，涂覆在正极上，静置干燥后，得到含有聚合物保护层(厚度约1nm)的正极。将含有保护层的正极用于锂离子电池中，在1.0C充放电下，电池循环100圈后，放电比容量为141mAh/g，效率稳定在99％以上。In the glove box, polymer P1

(n=80) in chloroform solution (25wt%), coated on the positive electrode, and after standing and drying, a positive electrode containing a polymer protective layer (thickness about 1 nm) was obtained. The positive electrode containing the protective layer is used in the lithium-ion battery. Under 1.0C charge and discharge, after 100 cycles of the battery, the discharge specific capacity is 141mAh/g, and the efficiency is stable above 99%.

Example 2

(n＝40,20wt％)涂覆在正极上，静置干燥后，得到含有聚合物保护层(厚度约15μm)的正极。将含有保护层的正极用于锂离子电池中，在1.0C充放电下，电池循环100圈后，放电比容量仍保持126mAh/g。In the glove box, polymer P2

(n=40, 20wt%) was coated on the positive electrode, and after standing and drying, a positive electrode containing a polymer protective layer (thickness about 15 μm) was obtained. The positive electrode containing the protective layer is used in the lithium-ion battery. Under 1.0C charge and discharge, the discharge specific capacity still maintains 126mAh/g after 100 cycles of the battery.

Example 3

(n＝5)的N,N-二甲基甲酰胺溶液(50wt％)，涂覆在正极上，静置干燥。将含有聚合物保护层(厚度约50μm)的正极用于锂硫电池中，在0.2C充放电下，电池循环200圈后，放电比容量仍保持891mAh/g，效率保持在99％以上。In the glove box, polymer P3

(n=5) N,N-dimethylformamide solution (50wt%), coated on the positive electrode, and left to dry. A positive electrode containing a polymer protective layer (thickness about 50 μm) is used in a lithium-sulfur battery. After 200 cycles of charging and discharging at 0.2C, the discharge specific capacity still maintains 891mAh/g, and the efficiency remains above 99%.

Example 4

(m＝100,n＝80)与LiDFOB(massratio＝10:70:20)在二甲基亚砜中混合溶解，然后以玻璃纤维为支撑材料，制备电解质复合隔膜，将其应用在碳锡复合材料/三元材料电池中，从图4中可以看出，0.5C下电池循环100圈后具有95％的容量保持率。In the glove box, the block copolymer P4

(m=100, n=80) and LiDFOB (massratio=10:70:20) were mixed and dissolved in dimethyl sulfoxide, and then glass fiber was used as a support material to prepare an electrolyte composite separator, which was applied in carbon-tin composite In the material/ternary material battery, it can be seen from Figure 4 that the battery has a capacity retention rate of 95% after 100 cycles at 0.5C.

Example 5

与Li₇La₃Zr₂O₁₂在二甲基亚砜(30wt％)中混合溶解，压片制得固态电解质，与正负极材料组装电池。In the glove box, polymer P5

Mix and dissolve Li ₇ La ₃ Zr ₂ O ₁₂ in dimethyl sulfoxide (30wt%), press into tablets to prepare a solid electrolyte, and assemble batteries with positive and negative materials.

As shown in Figure 5, after 100 cycles at 0.5C, the capacity retention rate of the battery is 93.5%.

Example 6

(n＝3,m＝3)在N-甲基吡咯烷酮(20wt％)溶解后，涂覆在正极上，静置干燥。组装电池并对相应电池性能进行测试，如图6所示，电池具有优良的循环性能，0.5C循环50圈后依然具有140mAh/g的容量。In the glove box, place the oligomer P6

(n=3, m=3) After N-methylpyrrolidone (20wt%) was dissolved, it was coated on the positive electrode and left to dry. Assemble the battery and test the corresponding battery performance. As shown in Figure 6, the battery has excellent cycle performance, and still has a capacity of 140mAh/g after 50 cycles at 0.5C.

Example 7

(n＝10)在二甲基亚砜(25wt％)溶解后，涂覆在正极上，静置干燥。组装电池并对相应电池性能进行测试，如图7所示，电池具有优良的循环性能，0.5C循环100圈后仍然具有161mAh/g的放电比容量。In the glove box, the polymer P7

(n=10) After dissolving dimethyl sulfoxide (25 wt%), it was coated on the positive electrode and left to dry. Assemble the battery and test the performance of the corresponding battery. As shown in Figure 7, the battery has excellent cycle performance, and still has a discharge specific capacity of 161mAh/g after 100 cycles at 0.5C.

Example 8

(n＝m＝100)在氯仿(30wt％)溶解后，涂覆在正极上，静置干燥。组装电池并对相应电池性能进行测试，如图8所示，室温下电池具有优异的循环性能(充电截止电压为1.8-2.8V)，0.1C循环100圈后仍然具有900mAh/g的放电比容量。In the glove box, the random copolymer P8

(n=m=100) After dissolving in chloroform (30wt%), it was coated on the positive electrode and left to dry. Assemble the battery and test the performance of the corresponding battery. As shown in Figure 8, the battery has excellent cycle performance at room temperature (the charge cut-off voltage is 1.8-2.8V), and it still has a specific discharge capacity of 900mAh/g after 100 cycles at 0.1C .

Example 9

(n＝m＝200)在N,N-二甲基乙酰胺(35wt％)溶解后，涂覆在正极上，静置干燥。组装电池并对相应电池性能进行测试，如图9所示，电池具有优良的循环性能(充电截止电压为1.8-2.8V)，室温0.1C下循环100圈后仍然具有780mAh/g的放电比容量。In the glove box, the random polymer P9

(n=m=200) After N,N-dimethylacetamide (35wt%) was dissolved, it was coated on the positive electrode and left to dry. Assemble the battery and test the performance of the corresponding battery. As shown in Figure 9, the battery has excellent cycle performance (charging cut-off voltage is 1.8-2.8V), and after 100 cycles at room temperature 0.1C, it still has a discharge specific capacity of 780mAh/g .

Example 10

(n＝90)在二甲基亚砜(25wt％)溶解后，涂覆在正极上，静置干燥。组装电池并对相应电池性能进行测试，如图7所示，电池具有优良的循环性能(充电截止电压为3.0-4.8V)，0.5C室温下循环200圈后仍然具有120mAh/g的放电比容量，容量保持率为75％。In the glove box, polymer P10

(n=90) After dissolving dimethyl sulfoxide (25 wt%), it was coated on the positive electrode and left to dry. Assemble the battery and test the performance of the corresponding battery. As shown in Figure 7, the battery has excellent cycle performance (charging cut-off voltage is 3.0-4.8V), and it still has a discharge specific capacity of 120mAh/g after 200 cycles at room temperature of 0.5C , The capacity retention rate is 75%.

Example 11

(n＝70,m＝10)与LiPF₆(mass ratio＝15:65:20)在N,N-二甲基甲酰胺中混合溶解，然后以玻璃纤维为支撑材料，制备电解质复合隔膜，将其应用在锂金属/富锂锰基电池中，从图11中可以看出，0.5C下电池首圈循环的氧气产量相比于商用的液态电解质明显减少。In the glove box, the polymer P11

(n=70, m=10) and LiPF ₆ (mass ratio=15:65:20) were mixed and dissolved in N,N-dimethylformamide, and then glass fiber was used as a support material to prepare an electrolyte composite separator. It is applied in lithium metal/lithium-rich manganese-based batteries. It can be seen from Figure 11 that the oxygen production of the first cycle of the battery at 0.5C is significantly lower than that of commercial liquid electrolytes.

Example 12

(n＝30)在氯仿(35wt％)中溶解，作为粘结剂应用到锂金属/三元材料电池(占正极含量)中，并用原位电化学质谱测试其产气状况。从图12中可以看出，1C下电池首圈二氧化碳产量比商用电解液明显减少。In the glove box, polymer P12

(n=30) was dissolved in chloroform (35wt%), applied as a binder in lithium metal/ternary material batteries (accounting for positive electrode content), and its gas production status was tested by in-situ electrochemical mass spectrometry. It can be seen from Figure 12 that the carbon dioxide production in the first cycle of the battery at 1C is significantly lower than that of the commercial electrolyte.

Example 13

(n＝10)在二甲基亚砜(25wt％)溶解后，涂覆在正极上，静置干燥。组装电池石墨/镍锰酸锂电池，在室温1C下循环，并用原位电化学质谱测首圈电池产气量。如图13所示，一氧化碳的产量只有1.8g mol^-1,远低于商用电解液的一氧化碳产量。In the glove box, the polymer P13

(n=10) After dissolving dimethyl sulfoxide (25 wt%), it was coated on the positive electrode and left to dry. Assemble the battery graphite/lithium nickel manganese oxide battery, cycle at room temperature 1C, and use in-situ electrochemical mass spectrometry to measure the gas production of the battery in the first cycle. As shown in Figure 13, the production of carbon monoxide is only 1.8g mol ^-1 , much lower than that of commercial electrolytes.

Example 14

(n＝20,m＝100)作为粘结剂(0.001％)，制备镍锰酸锂正极。组装的石墨/镍锰酸锂电池，在室温2C下循环300圈后，容量保持率为80％。random copolymer P14

(n=20, m=100) was used as a binder (0.001%) to prepare a lithium nickel manganese oxide positive electrode. The assembled graphite/lithium nickel manganese oxide battery has a capacity retention rate of 80% after 300 cycles at room temperature 2C.

Example 15

(n＝5,m＝60)作为粘结剂(20％)，制备镍钴锰酸锂(NCM532)正极。组装的电池在60度2C下循环200圈后，容量保持率为53％。The block copolymer P15

(n=5, m=60) was used as a binder (20%) to prepare a positive electrode of nickel cobalt lithium manganese oxide (NCM532). The assembled battery has a capacity retention rate of 53% after 200 cycles at 60°C and 2C.

Example 16

(n＝2000,m＝10)作为粘结剂(10％)，制备镍钴锰酸锂(NCM111)正极。组装的电池在60度1C下循环100圈后，容量保持率为90％。Copolymer P16

(n=2000, m=10) was used as a binder (10%) to prepare a positive electrode of nickel cobalt lithium manganese oxide (NCM111). The assembled battery has a capacity retention rate of 90% after 100 cycles at 60°C and 1C.

Testing battery performance involves the following steps:

(1) Preparation of positive electrode sheet

A Dissolve polyvinylidene fluoride (PVDF) in N-methylpyrrolidone at a concentration of 0.1mol/L.

B After mixing the binder, positive electrode active material, and conductive carbon black at a mass ratio of 10:80:10, grind for at least 1 hour.

C Scrape the slurry obtained in the previous step evenly on the aluminum foil with a thickness of 100-120 μm, first dry it in an oven at 60°C, then dry it in a vacuum oven at 120°C, roll it, punch it, weigh it and continue to dry it at 120°C °C in a vacuum oven and stored in a glove box for later use.

(2) Preparation of negative electrode sheet

A Dissolve PVDF in N-methylpyrrolidone at a concentration of 0.1mol/L.

B Mix PVDF, negative electrode active material, and conductive carbon black at a mass ratio of 10:80:10, and grind for at least 1 hour.

C Scrape the slurry obtained in the previous step evenly on the copper foil with a thickness of 100-120μm, first dry it in an oven at 60°C, then dry it in a vacuum oven at 120°C, roll it, punch it, weigh it and continue to dry it. Dry in a vacuum oven at 120°C and store in a glove box for later use.

(3) Battery assembly

The corresponding half-cell or battery structure is placed in the battery case, and the battery is obtained by sealing.

(4) Battery electrical performance test

The long-term cycle performance and rate performance of the secondary lithium battery were tested with a LAND battery charge and discharge instrument.

The above-mentioned embodiments are only examples for clearly illustrating the present invention, rather than limiting the implementation of the present invention. For those of ordinary skill in the art, other changes or changes in different forms can be made on the basis of the above description. All the implementation manners cannot be exhaustively listed here. All obvious changes or variations derived from the technical solutions of the present invention are still within the protection scope of the present invention.

Claims (12)

1. Use of a polymer comprising a hindered amine structure in a secondary lithium battery, wherein: the polymer has a structure shown in a general formula (1):

wherein m is 0-2000 and n is 1-2000; a. The ₁ 、A ₂ Each independently selected from H, COOH, CN, CONH ₂ An alkoxycarbonyl group not more than eighteen carbon atoms, a perfluoroalkoxycarbonyl group not more than eighteen carbon atoms, an alkylaminoacyl group not more than eighteen carbon atoms, an alkyl group not more than eighteen carbon atoms, an alkoxy group not more than eighteen carbon atoms, an aryl group not more than eighteen carbon atoms,

the value of a is 1 to 250,

the value of b is 1 to 250,

c takes a value of 1 to 250;

B ₁ is taken from NH, O, OCH ₂ ；E ^- Is taken from PF ₆ ^- ，BF ₄ ^- ，TFSI ^- ，FSI ^- ，CH ₃ OSO ₃ ^- ，

B ₂ Taken from NH, O, OCH ₂ ，

v is 1-4; b is selected from O, OCH ₂ (ii) a The value of W is 0-4; x is selected from H, oxygen free radical, alkoxy under octadecyl, alkyl under octadecyl, acyl under octadecyl; y is selected from H, methyl, methoxy, CN, F; z is selected from H, methyl, trifluoromethyl, chloromethyl, cyanomethyl;

the lithium battery comprises a negative electrode, a positive electrode, a diaphragm arranged between the negative electrode and the positive electrode and a non-aqueous electrolyte; the positive electrode comprises a positive active material, a binder, a conductive carbon material and a current collector; the polymer is coated on the surface of the positive electrode of the lithium battery;

the positive active material is one or more of lithium cobaltate, lithium manganese iron phosphate, lithium manganate, lithium nickel manganese oxide, lithium-rich manganese base, ternary material, lithium ion fluorophosphate and lithium manganese oxide;

the positive electrode having a surface coated with a polymer is prepared by the following method: dissolving a polymer in a solvent to form a uniform solution, spin-coating the solution containing the polymer on the surface of the positive electrode, and then drying the solution in a vacuum drying oven at 80 ℃ to obtain the positive electrode containing the polymer coating, wherein the thickness of the coating is 0.001-10 mu m.

2. The use of a polymer containing a hindered amine structure in a secondary lithium battery as claimed in claim 1, wherein: the polymer is selected from:

n＝80、

n＝40、

n＝5、

n＝3,m＝3、

n＝10、

n＝m＝100、

n＝m＝200、

n＝90、

n＝10。

3. the use of a polymer containing a hindered amine structure in a secondary lithium battery as claimed in claim 1, wherein: the active material of the negative electrode is one or more of metal lithium, metal lithium alloy, graphite, hard carbon, molybdenum disulfide, lithium titanate, carbon-silicon composite material, carbon-germanium composite material, carbon-tin composite material, antimony oxide, antimony-carbon composite material, tin-antimony composite material, lithium-titanium oxide and lithium metal nitride;

the binder of the positive electrode contains one or more polymers of claim 1, wherein the polymers account for 0.001-20% of the positive electrode material;

the diaphragm material is one of a cellulose non-woven film, a alginate fiber non-woven film, an aramid fiber non-woven film, a polyarylsulfone amide non-woven film, a polypropylene non-woven film, glass fiber, a polyethylene terephthalate film and a polyimide non-woven film;

the non-aqueous electrolyte comprises lithium salt, organic matrix and inorganic lithium ion conductor.

4. Use of a polymer comprising a hindered amine structure according to claim 3 in a secondary lithium battery, wherein: the lithium salt is lithium hexafluorophosphate (LiPF) ₆ ) Lithium perchlorate (LiClO) ₄ ) Lithium bis (oxalato) borate (LiBOB), lithium difluoro (oxalato) borate (LiDFOB), lithium trifluoro (CF) ₃ SO ₃ One or more of Li), lithium bis (trifluoromethyl) sulfonyl imide (LiTFSI) and lithium bis (fluoro) sulfonyl imide (LiFSI);

the organic matrix is selected from the following group: the material comprises a polymer containing a hindered amine structure, ethylene carbonate, dimethyl carbonate, ethyl methyl carbonate, propylene carbonate, diethyl carbonate, succinonitrile, ethanedinitrile, fluoroethylene carbonate, tetraethylene glycol dimethyl ether, sulfolane, polyethylene carbonate, polyacrylonitrile, polymethacrylate, polyethylene carbonate and polypropylene carbonate;

the inorganic lithium ion conductor is Li _3a La _(2/3)-a TiO ₃ ,0.04<a<0.14、Li _3+a X _a Y _1-a O ₄ ,X＝Si、Sc、Ge、Ti；Y＝P、As、V、Cr，0<a<1、LiZr ₂ (PO ₄ ) ₃ 、Li ₇ La ₃ Zr ₂ O ₁₂ 、Li _1+a Al _a Ti _2-a (PO ₄ ) ₃ ,0<a<2、Li _{1+ a} Al _a Ge _2-a (PO ₄ ) ₃ ,0<a<2、Li ₃ OCl、Li ₃ OCl _0.5 Br _0.5 、Li ₁₀ GeP ₂ S ₁₂ 、Li ₁₄ Zn(GeO ₄ ) ₄ 、Li ₅ La ₃ M ₂ O ₁₂ ,M＝Ta、Nb、Li _5.5 La ₃ Nb _1.75 In _0.25 O ₁₂ 、Li ₃ N-LiX,X＝Cl、Br、I、Li _9-na M _a N ₂ Cl ₃ ,M＝Na、K、Rb、Cs、Mg、Al，0<a<9，0<n<4、3Li ₃ N-MI,X＝Li、Na、K、LiPON、Li ₂ S-M _a S _b ,M＝Al、Si、P，0<a<3，0<b<6、Li ₆ PS ₅ X, X = F, cl, br, I.

5. The use of a polymer comprising a hindered amine structure in a secondary lithium battery as claimed in claim 1, wherein: the solvent for dissolving the polymer is one or more of dichloromethane, chloroform, 1,4-dioxane, glycol dimethyl ether, acetone, acetonitrile, dimethyl sulfoxide, sulfolane, dimethyl sulfite, diethyl sulfite, tetrahydrofuran, 1,2-dichloroethane, ethyl acetate, N-methylpyrrolidone, N-dimethylformamide and N, N-dimethylacetamide, and the polymer accounts for 10-80% of the total weight of the solution.

6. The use according to claim 1, wherein the lithium ion fluorophosphate is selected from the group consisting of: lithium vanadium fluorophosphate, lithium iron fluorophosphate.

7. A lithium secondary battery comprising a negative electrode, a positive electrode, a separator interposed between the negative electrode and the positive electrode, and a nonaqueous electrolyte; wherein,

the positive electrode comprises a positive active material, a binder, a conductive carbon material and a current collector;

the positive active material is one or more of lithium cobaltate, lithium manganese iron phosphate, lithium manganate, lithium nickel manganese, lithium-rich manganese base, ternary material, lithium ion fluorophosphate and lithium manganese oxide;

the surface of the lithium battery positive electrode is coated with a polymer with a hindered amine structure;

the positive electrode having a polymer coated surface was prepared by the following method: dissolving a polymer in a solvent to form a uniform solution, spin-coating the solution containing the polymer on the surface of a positive electrode, and then drying the solution in a vacuum drying oven at 80 ℃ to obtain the positive electrode containing a polymer coating, wherein the thickness of the coating is 0.001-10 mu m;

the polymer has a structure shown in a general formula (1):

wherein m is 0-2000 and n is 1-2000; a. The ₁ 、A ₂ Independently of each other from H, COOH, CN, CONH ₂ Alkoxycarbonyl of not more than eighteen carbon, perfluoroalkoxycarbonyl of not more than eighteen carbon, alkylaminoacyl of not more than eighteen carbon, alkyl of not more than eighteen carbon, decaAlkoxy of eight carbons or less, aryl of eighteen carbons or less,

the value of a is 1 to 250,

the value of b is 1 to 250,

c takes a value of 1 to 250;

B ₁ is taken from NH, O, OCH ₂ ；E ^- Is taken from PF ₆ ^- ，BF ₄ ^- ，TFSI ^- ，FSI ^- ，CH ₃ OSO ₃ ^- ，

B ₂ Is taken from NH, O, OCH ₂ ，

v is 1-4; b is selected from O, OCH ₂ (ii) a The value of W is 0-4; x is selected from H, oxygen free radical, alkoxy under octadecyl, alkyl under octadecyl, acyl under octadecyl; y is selected from H, methyl, methoxy, CN, F; z is selected from H, methyl, trifluoromethyl, chloromethyl and cyanomethyl.

8. A lithium secondary battery as claimed in claim 7, characterized in that said polymer is selected from the group consisting of:

n＝80、

n＝40、

n＝5、

n＝3,m＝3、

n＝10、

n＝m＝100、

n＝m＝200、

n＝90、

n＝10。

9. the secondary lithium battery as claimed in claim 7, wherein the active material of the negative electrode is one or more of metallic lithium, metallic lithium alloy, graphite, hard carbon, molybdenum disulfide, lithium titanate, carbon-silicon composite material, carbon-germanium composite material, carbon-tin composite material, antimony oxide, antimony-carbon composite material, tin-antimony composite material, lithium-titanium oxide, and lithium metal nitride;

the binder of the positive electrode contains one or more polymers of claim 1, wherein the polymers account for 0.001-20% of the positive electrode material;

the diaphragm material is one of a cellulose non-woven film, a alginate fiber non-woven film, an aramid fiber non-woven film, a polyarylsulfone amide non-woven film, a polypropylene non-woven film, glass fiber, a polyethylene terephthalate film and a polyimide non-woven film;

the non-aqueous electrolyte comprises lithium salt, organic matrix and inorganic lithium ion conductor.

10. The secondary lithium battery of claim 9 wherein said lithium salt is lithium hexafluorophosphate (LiPF) ₆ ) Lithium perchlorate (LiClO) ₄ ) Lithium bis (oxalato) borate (LiBOB), lithium difluoro (oxalato) borate (LiDFOB), lithium trifluoro (CF) ₃ SO ₃ Li), lithium bis (trifluoromethyl) sulfonyl imide (LiTFSI) and lithium bis (fluoro) sulfonyl imide (LiFSI);

the organic matrix is selected from the following group: the material comprises a polymer containing a hindered amine structure, ethylene carbonate, dimethyl carbonate, ethyl methyl carbonate, propylene carbonate, diethyl carbonate, succinonitrile, ethanedinitrile, fluoroethylene carbonate, tetraethylene glycol dimethyl ether, sulfolane, polyethylene carbonate, polyacrylonitrile, polymethacrylate, polyethylene carbonate and polypropylene carbonate;

the inorganic lithium ion conductor is Li _3a La _(2/3)-a TiO ₃ ,0.04<a<0.14、Li _3+a X _a Y _1-a O ₄ ,X＝Si、Sc、Ge、Ti；Y＝P、As、V、Cr，0<a<1、LiZr ₂ (PO ₄ ) ₃ 、Li ₇ La ₃ Zr ₂ O ₁₂ 、Li _1+a Al _a Ti _2-a (PO ₄ ) ₃ ,0<a<2、Li _{1+ a} Al _a Ge _2-a (PO ₄ ) ₃ ,0<a<2、Li ₃ OCl、Li ₃ OCl _0.5 Br _0.5 、Li ₁₀ GeP ₂ S ₁₂ 、Li ₁₄ Zn(GeO ₄ ) ₄ 、Li ₅ La ₃ M ₂ O ₁₂ ,M＝Ta、Nb、Li _5.5 La ₃ Nb _1.75 In _0.25 O ₁₂ 、Li ₃ N-LiX,X＝Cl、Br、I、Li _9-na M _a N ₂ Cl ₃ ,M＝Na、K、Rb、Cs、Mg、Al，0<a<9，0<n<4、3Li ₃ N-MI,X＝Li、Na、K、LiPON、Li ₂ S-M _a S _b ,M＝Al、Si、P，0<a<3，0<b<6、Li ₆ PS ₅ X, X = F, cl, br and I.

11. The lithium secondary battery of claim 7 wherein the solvent to dissolve the polymer is one or more of dichloromethane, chloroform, 1,4-dioxane, ethylene glycol dimethyl ether, acetone, acetonitrile, dimethyl sulfoxide, sulfolane, dimethyl sulfite, diethyl sulfite, tetrahydrofuran, 1,2-dichloroethane, ethyl acetate, N-methylpyrrolidone, N-dimethylformamide, and N, N-dimethylacetamide, and wherein the polymer comprises 10% to 80% of the total weight of the solution.

12. A lithium secondary battery as claimed in claim 7, characterized in that the lithium ion fluorophosphate is selected from the group consisting of: lithium vanadium fluorophosphate, lithium iron fluorophosphate.

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