Battery cell gas absorption and enrichment material, preparation method thereof and anti-bulge lithium battery

Abstract

The invention discloses a cell gas absorption and enrichment material, a preparation method thereof and an anti-bulge lithium battery in the field of battery cells, the material is composed of a conductive support skeleton, a gradient adsorption layer coated on the surface of the conductive support skeleton, and a catalytic conversion layer deposited on the surface of the gradient adsorption layer, and carrying out pre-expansion treatment and gas-permeable membrane packaging. Boron-doped graphene aerogel with a Li3PO4 nano layer deposited on the surface is adopted as the conductive supporting framework; the gradient adsorption layer comprises a first-stage adsorption layer and a second-stage adsorption layer, the first-stage adsorption layer adopts ZIF-8 active carbon core-shell slurry, and the second-stage adsorption layer adopts amino modified MIL-101 (Cr) slurry; and the catalytic conversion layer adopts a MnO2-Ni3N heterojunction nano array with an ALD porous protective film deposited on the surface. The invention solves the problems of low overall absorptivity, obvious volume expansion after adsorption and poor electrochemical safety when the existing carbon porous material adsorbs complex cell gas.

Description

Technical Field

[0001] The present invention relates to the field of battery cells, and in particular to a battery cell gas absorption and enrichment material, a preparation method thereof, and an anti-bulging lithium battery. Background Art

[0002] The generation of gases during battery cell charge and discharge cycles and use is a common phenomenon, both under normal operating conditions and under extreme conditions such as high temperatures. For example, during normal use, electrolyte redox decomposition occurs. In the high-potential region of the positive electrode, electrolyte solvent molecules lose electrons and are oxidized, producing gases such as CO2 and CO. In the low-potential region of the negative electrode, solvent molecules gain electrons and are reduced, producing alkanes (such as CH4 and C2H6) and alkenes (such as C2H4). This process is directly related to the battery's charge and discharge state and continues during normal cycles, as an unavoidable side reaction. Furthermore, the solid electrolyte interface (SEI) film forms during the initial charge and discharge (formation) of the battery, a process that produces gases such as CO, CO2, and C2H4. As the battery cycles, the SEI film continuously breaks down and repairs, with each repair process accompanied by new gas production reactions. This gas production mechanism persists throughout the battery's life cycle and is particularly pronounced in high-temperature environments. Under high temperature or extreme conditions, the SEI film will undergo thermal decomposition. That is, when the temperature exceeds 80-120°C, the unstable components in the SEI film (such as ROCO2Li) begin to decompose, releasing gases such as CO2 and accompanied by exothermic reactions, which may further accelerate the thermal runaway process. In addition, binders such as PVDF and CMC commonly used in negative electrodes will decompose to produce H2 at high temperatures or high reduction potentials; at the same time, the high-nickel ternary positive electrode (such as NCM811, NCA) has an unstable lattice structure at high temperatures (greater than 180°C) and deep delithiation state, and will release reactive oxygen (O2). These reactive oxygen species further react with the electrolyte to produce a large amount of CO and CO2 gases, while releasing a large amount of heat.

[0003] In summary, the gases produced during thermal runaway in lithium-ion batteries have a complex composition, but are primarily concentrated in CO2 (35-50%), CO (25-35%), H2 (15-25%), C2H4 (5-10%), and CH4 (3-8%), accounting for over 99% of the total gas volume. If these gases cannot be promptly discharged, they can trigger a series of chain reactions within the battery and at the system level. The most common hazard is battery swelling, which can lead to battery shell rupture and electrolyte leakage, and even ignite combustible gas explosions and thermal runaway chain reactions.

[0004] Currently, the industry has developed a multi-layered approach to addressing battery gassing, from source suppression to process control and end-of-line protection, forming a comprehensive prevention and control system. First, pressure relief and venting technologies are used, including mechanical pressure relief valves, active venting systems, and thermal runaway directional diversion. Second, environmental control is strengthened, including intelligent charging management, intelligent temperature regulation, and over-discharge protection. Furthermore, materials and designs for electrolytes, electrodes, and other components can be optimized. For example, patent publication number CN118160141A discloses a battery cell venting channel, a battery device, and a method for venting gas from a battery, which can effectively and safely remove harmful gases from the battery. However, this type of venting method has the following drawbacks: it only vents high-temperature flammable gases from the battery system, without addressing the flammability / toxicity of the gases. Gases discharged outside the vehicle may still accumulate to explosive limits in confined spaces (such as garages), spontaneously combust on contact with air, or pose a threat to personnel safety. If the exhaust is connected to a collection device, the collection device, combined with the existing chamber and diversion channel, increases the battery pack's volume, reducing the battery pack's energy density.

[0005] To this end, a direct adsorption method can be used to allow the gas to be absorbed directly inside the battery cell, avoiding or reducing external discharge. For example, in the patent document with publication number CN110050375A and the applicant being "Kurita Industry Co., Ltd.", a carbon-based porous material is disclosed that can be used to absorb methane gas generated when lithium-ion batteries are abnormal, etc.; for another example, in the patent document with publication number CN117477049A and the applicant being "Beijing Xibei Power Technology Co., Ltd.", a battery for absorbing and channeling gas and a battery cell containing the same are disclosed, which also uses a conductive porous carbon material for battery cell gas adsorption. However, these carbon-based porous materials are not suitable for complex battery cell gases with multiple components, have a low overall absorption rate, and have problems such as significant volume expansion after adsorption and poor electrochemical safety. Summary of the Invention

[0006] The purpose of the present invention is to provide a battery cell gas absorption and enrichment material, a preparation method thereof, and an anti-bulging lithium battery, which solves the problems of low overall absorption rate, obvious volume expansion after adsorption, and poor electrochemical safety of existing carbon-based porous materials when adsorbing complex battery cell gases.

[0007] The present invention achieves the above-mentioned purpose through the following technical solutions: A gas absorption and enrichment material for a battery core, comprising a conductive support skeleton, a gradient adsorption layer coated on the surface of the conductive support skeleton, and a catalytic conversion layer deposited on the surface of the gradient adsorption layer, and is obtained after pre-expansion treatment and breathable membrane packaging; Wherein, the conductive support skeleton adopts boron-doped graphene aerogel with a Li3PO4 nanolayer deposited on the surface; The gradient adsorption layer comprises a primary adsorption layer and a secondary adsorption layer coated in turn from inside to outside, the primary adsorption layer adopts ZIF-8@ activated carbon core-shell slurry, and the secondary adsorption layer adopts amino-modified MIL-101(Cr) slurry. The catalytic conversion layer adopts MnO2-Ni3N heterojunction nanoarray with ALD porous protective film deposited on the surface.

[0008] The application further provides a preparation method of the battery cell gas absorption enrichment material. S1, taking boric acid and graphene oxide dispersion liquid in turn for ultrasonic mixing, hydrothermal reduction and freeze drying to obtain boron-doped graphene aerogel, then taking ethanol solution as a solvent, adding LiOH and H3PO4 and reacting to obtain a Li3PO4 precursor solution, and depositing the Li3PO4 precursor solution on the surface of the boron-doped graphene aerogel by an immersion-tow draw method to obtain a conductive support framework; S2, ZIF-8@ activated carbon core-shell particles are prepared, added into N-methyl pyrrolidone, and additives are added to obtain ZIF-8@ activated carbon core-shell slurry; Cr(NO3)3·9H2O, terephthalic acid and 2-amino terephthalic acid are mixed, and hydrothermal synthesis is performed to obtain amino-modified MIL-101(Cr), which is added into N-methyl pyrrolidone, and additives are added to obtain amino-modified MIL-101(Cr) slurry; S3, the ZIF-8@ activated carbon core-shell slurry and the amino-modified MIL-101(Cr) slurry are coated in turn on the surface of the conductive support framework, and then vacuum drying and hot pressing are performed to obtain a gradient adsorption layer; S4, taking a mixed aqueous solution of MnSO4 and Na2SO4 as an electrodeposition liquid, performing electrodeposition on the surface of the gradient adsorption layer to obtain a MnO2 nanowire array, then immersing the MnO2 nanowire array in a NiCl2 solution, taking out and blowing nitrogen, then performing nitridation treatment to obtain a MnO2-Ni3N heterojunction nanoarray, and finally taking trimethylaluminum and deionized water as alternating precursors to perform atomic layer deposition of an ALD porous protective film on the surface of the array to obtain a catalytic conversion layer; S5, taking the product of step S4 for pre-expansion treatment and air-permeable membrane packaging to obtain the battery cell gas absorption enrichment material.

[0009] Further improvements are that in step S1, the mass concentration of the graphene oxide dispersion is 2-2.5%, the amount ratio of boric acid to graphene oxide dispersion is 0.5g:450-550mL, the frequency of the ultrasonic mixing is 35-45kHz, the time is 1-1.2h, the temperature of the hydrothermal reduction is 170-180°C, the time is 5-8h, the temperature of the freeze-drying is -40 to -50°C, the time is 36-48h, the mass concentration of the ethanol solution is 65-75%, the added concentration of LiOH is 0.08-0.12M, and the added concentration of H3PO4 is 0.025-0.035M; The pulling speed of the immersion pulling method is 10-12 mm / min, and after the pulling is completed, the sintering is carried out at 295-305° C. for 1-1.2 hours under nitrogen protection.

[0010] A further improvement is that in step S2, the specific operation of preparing ZIF-8@activated carbon core-shell particles is as follows: taking activated carbon and washing it to neutrality after refluxing with concentrated nitric acid, then taking Zn(NO3)2·6H2O and 2-methylimidazole and dissolving them in methanol to obtain a coating solution, adding activated carbon to the coating solution, stirring at room temperature for 24-32 hours, and then centrifuging to obtain ZIF-8@activated carbon core-shell particles; The reflux temperature of the concentrated nitric acid is 80-85°C for 2.5-3.5 hours, the dosage ratio of Zn(NO3)2·6H2O, 2-methylimidazole and methanol is 5.95g:6.5g:500-550mL, and the dosage ratio of the activated carbon to the coating liquid is 10g:400-600mL.

[0011] A further improvement is that in step S2, the mass ratio of the Cr(NO3)3·9H2O, terephthalic acid and 2-aminoterephthalic acid is 1:0.4:0.1, and the hydrothermal synthesis refers to first reacting at 145-155°C for 10-14 hours, then Soxhlet extraction with methanol for 36-48 hours, and finally vacuum activation at 145-155°C.

[0012] A further improvement is that in step S2, the additives in the ZIF-8@activated carbon core-shell slurry include polyvinylidene fluoride-hexafluoropropylene copolymer, lithium bis(trifluoromethanesulfonyl imide), hydrophobic SiO2 nanospheres and multi-walled carbon nanotubes, and the mass proportions of each component are: ZIF-8@activated carbon core-shell particles 42-48%, polyvinylidene fluoride-hexafluoropropylene copolymer 10-15%, lithium bis(trifluoromethanesulfonyl imide 2-4%, hydrophobic SiO2 nanospheres 2-4%, multi-walled carbon nanotubes 1-3% and N-methylpyrrolidone 32-38%; The additives in the amino-modified MIL-101 (Cr) slurry include polyvinylidene fluoride-hexafluoropropylene copolymer, lithium bis(trifluoromethanesulfonyl imide) and carbon black, and the mass proportion of each component is: amino-modified MIL-101 (Cr) 32-38%, polyvinylidene fluoride-hexafluoropropylene copolymer 12-18%, lithium bis(trifluoromethanesulfonyl imide) 2-5%, carbon black 1-2% and N-methylpyrrolidone 40-50%.

[0013] Further improvements are that in step S3, the wet film thickness of the ZIF-8@activated carbon core-shell slurry is 90-110 μm, the wet film thickness of the amino-modified MIL-101 (Cr) slurry is 70-80 μm, the vacuum drying temperature is 70-80 ° C, the time is 1.8-2.2 h, the hot pressing temperature is 110-120 ° C, the pressure is 8-12 MPa, and the time is 4-6 min.

[0014] A further improvement is that in step S4, the concentrations of MnSO4 and Na2SO4 are both 0.08-0.12M, the electrodeposition voltage is 0.8V vs. Ag / AgCl, the time is 20±2min, and the temperature is 25±1°C; The concentration of the NiCl2 solution is 0.04-0.06M, the immersion time is 4-6 minutes, and the nitriding treatment refers to the reaction at 398-402°C in an NH3 atmosphere for 0.8-1.2 hours; The temperature of the atomic layer deposition is 120±2° C., the number of cycles is 15 cycles, and the growth rate per cycle is 0.11±0.01 nm / cycle.

[0015] A further improvement is that in step S5, the pre-expansion treatment refers to placing the product in an autoclave, filling it with N2 to 0.5±0.02MPa and maintaining the pressure for 1-1.2h, and then releasing the pressure to normal pressure at a rate of 0.02-0.04MPa / min. The breathable membrane packaging refers to hot-pressing the product with an ePTFE membrane with a thickness of 45-55μm and a pore size of 0.2±0.02μm. The hot pressing temperature is 140-150℃, the pressure is 0.4-0.6MPa, and the time is 8-10s.

[0016] The present invention also provides an anti-bulging lithium battery, the battery cell of which includes a positive electrode collector, a positive electrode coating, a separator, a negative electrode coating, a negative electrode collector and an electrolyte arranged in sequence, and the battery cell top sealing area is provided with the battery cell gas absorption and enrichment material.

[0017] The beneficial effects of the present invention are: (1) The present invention achieves coordinated processing of battery cell gases through catalytic conversion and gradient adsorption, and ultimately achieves efficient adsorption and fixation. It can be used for gas adsorption and enrichment under normal battery operating conditions (non-thermal runaway), avoiding or significantly reducing gas escape. Among them, the MnO2-Ni3N heterojunction nanoarray structure converts CO / H2 into inert CO2 / NH3, the ZIF-8@activated carbon core-shell structure can efficiently capture CO2 and C2H4, and the amino-modified MIL-101(Cr) structure can fix CO and CH4 through coordination, and can also adsorb NH3 secondary.

[0018] (2) The present invention uses boron-doped graphene aerogel as a conductive support skeleton to provide mechanical support and electronic conduction paths, and to reserve gas diffusion channels. It also has a certain elastic modulus and can resist adsorption stress. At the same time, after pre-expansion treatment, the overall volume expansion rate of the material can be significantly reduced; (3) The present invention can block the penetration of electrolyte by depositing a Li3PO4 nanolayer on the surface of the conductive support skeleton, and at the same time, an ALD porous protective film is deposited on the surface of the MnO2-Ni3N heterojunction nanoarray using atomic layer deposition technology. The use of grain boundary channels does not affect the adsorption effect, but also prevents metal dissolution from contaminating the electrolyte, reduces electrochemical interference, and maintains the catalytic mechanism. In addition, the use of Ni3N catalysis can avoid the use of precious metals, prevent reduced metals from causing short circuits, and has high safety and stability. DETAILED DESCRIPTION

[0019] The present application is further described in detail below in conjunction with specific embodiments. It is necessary to point out here that the following specific implementation methods are only used to further illustrate the present application and cannot be understood as limiting the scope of protection of the present application. Technical personnel in this field can make some non-essential improvements and adjustments to the present application based on the above application content.

[0020] 1. Implement the experiment Unless otherwise specified, the raw materials used in this experiment were common commercially available raw materials.

[0021] Example 1 A method for preparing a gas absorption and enrichment material for a battery cell, the method comprising the following steps: S1. Boric acid and a graphene oxide dispersion with a mass concentration of 2% are taken, and the amount ratio of boric acid to graphene oxide dispersion is 0.5g:450mL. The mixture is ultrasonically mixed (frequency is 35kHz, time is 1.2h), hydrothermally reduced (temperature is 170℃, time is 8h) and freeze-dried (temperature is -40℃, time is 48h) to obtain a boron-doped graphene aerogel. Then, 0.08M LiOH and 0.025M H3PO4 are added to an ethanol solution with a mass concentration of 65% as a solvent and reacted to obtain a Li3PO4 precursor solution. The Li3PO4 precursor solution is deposited on the surface of the boron-doped graphene aerogel by an immersion pulling method at a pulling speed of 10mm / min. After the pulling is completed, the mixture is sintered at 295℃ under nitrogen protection for 1.2h to obtain a conductive support skeleton; S2. Prepare ZIF-8@activated carbon core-shell particles, specifically: take activated carbon and wash it to neutrality after refluxing with concentrated nitric acid, then take Zn(NO3)2·6H2O and 2-methylimidazole and dissolve them in methanol to obtain a coating liquid, add activated carbon to the coating liquid, stir at room temperature for 24 hours, and then collect by centrifugation to obtain ZIF-8@activated carbon core-shell particles; wherein the temperature of the concentrated nitric acid reflux is 80°C, the time is 3.5 hours, the amount ratio of the Zn(NO3)2·6H2O, 2-methylimidazole and methanol is 5.95g:6.5g:500mL, and the amount ratio of the activated carbon to the coating liquid is 10g:400mL.

[0022] ZIF-8@activated carbon core-shell particles were added to N-methylpyrrolidone, and additives were added to mix to obtain ZIF-8@activated carbon core-shell slurry; the slurry formula by mass fraction was: ZIF-8@activated carbon core-shell particles 42%, polyvinylidene fluoride-hexafluoropropylene copolymer 10%, lithium bis(trifluoromethanesulfonyl)imide 4%, hydrophobic SiO2 nanospheres 4%, multi-walled carbon nanotubes 3% and N-methylpyrrolidone 37%.

[0023] Cr(NO3)3·9H2O, terephthalic acid and 2-aminoterephthalic acid were mixed (mixing mass ratio of 1:0.4:0.1), and amino-modified MIL-101(Cr) was obtained by hydrothermal synthesis (first reacting at 145°C for 14 hours, then Soxhlet extraction with methanol for 36 hours, and finally vacuum activation at 145°C). The mixture was added to N-methylpyrrolidone, and auxiliary agents were added to obtain amino-modified MIL-101(Cr) slurry; the slurry formula by mass fraction was: 32% amino-modified MIL-101(Cr), 12% polyvinylidene fluoride-hexafluoropropylene copolymer, 5% lithium bis(trifluoromethanesulfonyl imide), 2% carbon black and 49% N-methylpyrrolidone.

[0024] S3, coating the surface of the conductive support skeleton with ZIF-8@activated carbon core-shell slurry and amino-modified MIL-101(Cr) slurry in sequence, the wet film thickness of the ZIF-8@activated carbon core-shell slurry was 90 μm, and the wet film thickness of the amino-modified MIL-101(Cr) slurry was 70 μm, and then vacuum drying and hot pressing were performed, the vacuum drying temperature was 70°C, the time was 2.2 h, and the hot pressing temperature was 110°C, the pressure was 8 MPa, and the time was 6 min, finally obtaining a gradient adsorption layer; S4. A mixed aqueous solution of MnSO4 and Na2SO4 with a concentration of 0.08M was used as an electrodeposition solution, and an MnO2 nanowire array was obtained by electrodeposition on the surface of the gradient adsorption layer. The electrodeposition voltage was 0.8V vs. Ag / AgCl, the time was 18min, and the temperature was 26°C. It was then immersed in a NiCl2 solution with a concentration of 0.04M for 6min, taken out and purged with nitrogen, and then nitrided (reacted at 398°C in an NH3 atmosphere for 1.2h) to obtain a MnO2-Ni3N heterojunction nanoarray. Finally, trimethylaluminum and deionized water were used as alternating precursors to atomically layer deposit an ALD porous protective film on the array surface. The temperature of the atomic layer deposition was 118°C, the number of cycles was 15 cycles, and the single-cycle growth rate was 0.11±0.01nm / cycle to obtain a catalytic conversion layer. S5. The product of step S4 is pre-expanded and packaged with a breathable membrane. The pre-expansion treatment refers to placing the product in an autoclave, filling it with N2 to 0.48 MPa and maintaining the pressure for 1.2 hours, and then releasing the pressure to normal pressure at a rate of 0.02 MPa / min. The breathable membrane packaging refers to hot-pressing the product with an ePTFE membrane having a thickness of 45 μm and a pore size of 0.2±0.02 μm. The hot pressing temperature is 140°C, the pressure is 0.4 MPa, and the time is 10 seconds to obtain the battery cell gas absorption and enrichment material.

[0025] Disclosed is a bulge-proof lithium battery. The battery cell of the bulge-proof lithium battery comprises a positive electrode current collector (15μm thick aluminum foil), a positive electrode coating (using NCM622 ternary material as an active material, conductive carbon black as a conductive agent, and PVDF as a binder), a separator (16μm thick ceramic-coated PE base film), a negative electrode coating (using artificial graphite as an active material, conductive carbon black as a conductive agent, and CMC / SBR as a binder), a negative electrode current collector (10μm thick copper foil), and an electrolyte (1.1 mol / L LiPF6 dissolved in a mixed solvent with a volume ratio of EC:EMC=3:7). The battery cell top seal area is provided with the battery cell gas absorption and enrichment material.

[0026] Example 2 A method for preparing a gas absorption and enrichment material for a battery cell, the method comprising the following steps: S1. Boric acid and a graphene oxide dispersion with a mass concentration of 2.2% are taken, and the amount ratio of boric acid to graphene oxide dispersion is 0.5g:500mL. The mixture is ultrasonically mixed (frequency is 40kHz, time is 1.1h), hydrothermally reduced (temperature is 175℃, time is 6h) and freeze-dried (temperature is -45℃, time is 42h) to obtain a boron-doped graphene aerogel. Then, 0.1M LiOH and 0.03M H3PO4 are added to an ethanol solution with a mass concentration of 70% as a solvent and reacted to obtain a Li3PO4 precursor solution. The Li3PO4 precursor solution is deposited on the surface of the boron-doped graphene aerogel by an immersion pulling method at a pulling speed of 11mm / min. After the pulling is completed, the mixture is sintered at 300℃ under nitrogen protection for 1.1 to obtain a conductive support skeleton. S2. Prepare ZIF-8@activated carbon core-shell particles, specifically: take activated carbon and wash it to neutrality after refluxing with concentrated nitric acid, then take Zn(NO3)2·6H2O and 2-methylimidazole and dissolve them in methanol to obtain a coating liquid, add activated carbon to the coating liquid, stir at room temperature for 28 hours, and then collect by centrifugation to obtain ZIF-8@activated carbon core-shell particles; wherein the temperature of the concentrated nitric acid reflux is 82°C, the time is 3 hours, the amount ratio of the Zn(NO3)2·6H2O, 2-methylimidazole and methanol is 5.95g:6.5g:520mL, and the amount ratio of the activated carbon to the coating liquid is 10g:500mL.

[0027] ZIF-8@activated carbon core-shell particles were added to N-methylpyrrolidone, and additives were added to mix to obtain ZIF-8@activated carbon core-shell slurry; the slurry formula by mass fraction was: 45% ZIF-8@activated carbon core-shell particles, 12% polyvinylidene fluoride-hexafluoropropylene copolymer, 3% lithium bis(trifluoromethanesulfonyl)imide, 3% hydrophobic SiO2 nanospheres, 2% multi-walled carbon nanotubes and 35% N-methylpyrrolidone.

[0028] Then, Cr(NO3)3·9H2O, terephthalic acid and 2-aminoterephthalic acid were mixed (the mixing mass ratio was 1:0.4:0.1), and amino-modified MIL-101(Cr) was obtained by hydrothermal synthesis (first reacting at 150°C for 12 hours, then Soxhlet extraction with methanol for 42 hours, and finally vacuum activation at 150°C). The mixture was added to N-methylpyrrolidone, and auxiliary agents were added to obtain amino-modified MIL-101(Cr) slurry; the slurry formula by mass fraction was: 35% amino-modified MIL-101(Cr), 15% polyvinylidene fluoride-hexafluoropropylene copolymer, 3% lithium bis(trifluoromethanesulfonyl imide), 1.5% carbon black and 45.5% N-methylpyrrolidone.

[0029] S3, coating ZIF-8@activated carbon core-shell slurry and amino-modified MIL-101(Cr) slurry on the surface of the conductive support framework in turn, the wet film thickness of the ZIF-8@activated carbon core-shell slurry is 100 μm, the wet film thickness of the amino-modified MIL-101(Cr) slurry is 75 μm, then vacuum drying and hot pressing, the temperature of the vacuum drying is 75℃, the time is 2h, the temperature of the hot pressing is 115℃, the pressure is 10 MPa, the time is 5 min, finally a gradient adsorption layer is obtained; S4, taking a mixed aqueous solution of MnSO4 and Na2SO4 with a concentration of 0.1 M as an electrodeposition solution, performing electrodeposition on the surface of the gradient adsorption layer to obtain a MnO2 nanowire array, the voltage of the electrodeposition is 0.8 V vs. Ag / AgCl, the time is 20 min, the temperature is 25℃, then immersing it in a NiCl2 solution with a concentration of 0.05 M for 5 min, taking it out and blowing nitrogen, then performing nitridation treatment (reacting in NH3 atmosphere at 400℃ for 1h) to obtain a MnO2-Ni3N heterojunction nanowire array, finally performing atomic layer deposition (ALD) of a porous protective film on the surface of the array by taking trimethylaluminum and deionized water as alternating precursors, the temperature of the atomic layer deposition is 120℃, the cycle number is 15 cycles, the single-cycle growth rate is 0.11±0.01 nm / cycle, and a catalytic conversion layer is obtained; S5, taking the product of step S4 to perform pre-expansion treatment and air-permeable film packaging, the pre-expansion treatment refers to placing the product in an autoclave, charging N2 to 0.5 MPa and maintaining the pressure for 1.1 h, and then releasing the pressure to normal pressure at a rate of 0.03 MPa / min, and the air-permeable film packaging refers to hot pressing the product with an ePTFE film with a thickness of 50 μm and a pore size of 0.2±0.02 μm, the hot pressing temperature is 145℃, the pressure is 0.5 MPa, and the time is 9 s, and the battery cell gas absorption and enrichment material is obtained.

[0030] A bulge-preventing lithium battery, the battery cell of the bulge-preventing lithium battery comprises, in sequence, a positive electrode current collector (15 μm thick aluminum foil), a positive electrode coating layer (using NCM622 ternary material as active material, conductive carbon black as conductive agent, and PVDF as binder), a separator (16 μm thick ceramic-coated PE-based film), a negative electrode coating layer (using artificial graphite as active material, conductive carbon black as conductive agent, and CMC / SBR as binder), a negative electrode current collector (10 μm thick copper foil), and an electrolyte (1.1 mol / L LiPF6 dissolved in a mixed solvent with a volume ratio of EC:EMC=3:7), and the battery cell top sealing area is provided with the battery cell gas absorption and enrichment material.

[0031] Example 3 A preparation method of a battery cell gas absorption and enrichment material, the method steps comprising: S1. Boric acid and a graphene oxide dispersion with a mass concentration of 2.5% are taken, and the amount ratio of boric acid to graphene oxide dispersion is 0.5g:550mL. The mixture is ultrasonically mixed (frequency is 45kHz, time is 1h), hydrothermally reduced (temperature is 180℃, time is 5h) and freeze-dried (temperature is -50℃, time is 36h) to obtain boron-doped graphene aerogel. Then, 0.12M LiOH and 0.035M H3PO4 are added to an ethanol solution with a mass concentration of 75% as a solvent and reacted to obtain a Li3PO4 precursor solution. The Li3PO4 precursor solution is deposited on the surface of the boron-doped graphene aerogel by an immersion pulling method at a pulling speed of 12mm / min. After the pulling is completed, the mixture is sintered at 305℃ under nitrogen protection for 1h to obtain a conductive support skeleton. S2. Prepare ZIF-8@activated carbon core-shell particles, specifically: take activated carbon and wash it to neutrality after refluxing with concentrated nitric acid, then take Zn(NO3)2·6H2O and 2-methylimidazole and dissolve them in methanol to obtain a coating liquid, add activated carbon to the coating liquid, stir at room temperature for 32 hours, and then collect by centrifugation to obtain ZIF-8@activated carbon core-shell particles; wherein the temperature of the concentrated nitric acid reflux is 85°C, the time is 2.5 hours, the amount ratio of the Zn(NO3)2·6H2O, 2-methylimidazole and methanol is 5.95g:6.5g:550mL, and the amount ratio of the activated carbon to the coating liquid is 10g:600mL.

[0032] ZIF-8@activated carbon core-shell particles were added to N-methylpyrrolidone, and additives were added to mix to obtain ZIF-8@activated carbon core-shell slurry; the slurry formula by mass fraction was: 48% ZIF-8@activated carbon core-shell particles, 15% polyvinylidene fluoride-hexafluoropropylene copolymer, 2% lithium bis(trifluoromethanesulfonyl)imide, 2% hydrophobic SiO2 nanospheres, 1% multi-walled carbon nanotubes and 32% N-methylpyrrolidone.

[0033] Then, Cr(NO3)3·9H2O, terephthalic acid and 2-aminoterephthalic acid were mixed (the mixing mass ratio was 1:0.4:0.1), and amino-modified MIL-101(Cr) was obtained by hydrothermal synthesis (first reacting at 155°C for 10 hours, then Soxhlet extraction with methanol for 48 hours, and finally vacuum activation at 155°C). The amino-modified MIL-101(Cr) was added to N-methylpyrrolidone, and auxiliary agents were added to mix to obtain amino-modified MIL-101(Cr) slurry; the slurry formula by mass fraction was: 38% amino-modified MIL-101(Cr), 18% polyvinylidene fluoride-hexafluoropropylene copolymer, 2% lithium bis(trifluoromethanesulfonyl imide), 1% carbon black and 41% N-methylpyrrolidone.

[0034] S3, coating ZIF-8@activated carbon core-shell slurry and amino-modified MIL-101(Cr) slurry on the surface of the conductive support framework in turn, the wet film thickness of the coated ZIF-8@activated carbon core-shell slurry is 110 μm, the wet film thickness of the coated amino-modified MIL-101(Cr) slurry is 80 μm, then vacuum drying and hot pressing, the temperature of the vacuum drying is 80℃, the time is 1.8h, the temperature of the hot pressing is 120℃, the pressure is 12MPa, the time is 4min, finally a gradient adsorption layer is obtained; S4, taking a mixed aqueous solution of MnSO4 and Na2SO4 with a concentration of 0.12M as an electrodeposition solution, performing electrodeposition on the surface of the gradient adsorption layer to obtain a MnO2 nanowire array, the voltage of the electrodeposition is 0.8V vs. Ag / AgCl, the time is 22min, the temperature is 24℃, then immersing it in a NiCl2 solution with a concentration of 0.06M for 4min, taking it out and blowing nitrogen, then performing nitridation treatment (reacting in NH3 atmosphere at 402℃ for 0.8h) to obtain a MnO2-Ni3N heterojunction nanowire array, finally performing atomic layer deposition (ALD) of a porous protective film on the surface of the array by taking trimethylaluminum and deionized water as alternating precursors, the temperature of the atomic layer deposition is 122℃, the cycle number is 15 cycles, the single-cycle growth rate is 0.11±0.01nm / cycle, to obtain a catalytic conversion layer; S5, taking the product of step S4 to perform pre-expansion treatment and air-permeable membrane packaging, the pre-expansion treatment refers to placing the product in an autoclave, charging N2 to 0.52MPa and maintaining the pressure for 1h, then releasing the pressure to normal pressure at a rate of 0.04MPa / min, the air-permeable membrane packaging refers to hot pressing composite of the product with an ePTFE membrane with a thickness of 55μm and a pore size of 0.2±0.02μm, the hot pressing temperature is 150℃, the pressure is 0.6MPa, the time is 8s, to obtain the cell gas absorption and enrichment material.

[0035] A bulge-preventing lithium battery, the cell of the bulge-preventing lithium battery comprises a positive electrode current collector (15μm thick aluminum foil), a positive electrode coating (NCM622 ternary material as active material, conductive carbon black as conductive agent, PVDF as binder), a separator (16μm thick ceramic coated PE-based film), a negative electrode coating (artificial graphite as active material, conductive carbon black as conductive agent, CMC / SBR as binder), a negative electrode current collector (10μm thick copper foil) and an electrolyte (1.1 mol / L LiPF6 dissolved in a mixed solvent with a volume ratio of EC:EMC=3:7) arranged in turn, and the cell top sealing area is provided with the cell gas absorption and enrichment material.

[0036] Comparative Example 1 A preparation method of a cell gas absorption and enrichment material, the method steps comprise: S1. Boric acid and a graphene oxide dispersion with a mass concentration of 2.2% are taken, with the amount ratio of boric acid to graphene oxide dispersion being 0.5 g:500 mL. The mixture is ultrasonically mixed (frequency: 40 kHz, time: 1.1 h), hydrothermally reduced (temperature: 175°C, time: 6 h), and freeze-dried (temperature: -45°C, time: 42 h) to obtain a boron-doped graphene aerogel, which is used as a conductive support skeleton. S2. Prepare ZIF-8@activated carbon core-shell particles, specifically: take activated carbon and wash it to neutrality after refluxing with concentrated nitric acid, then take Zn(NO3)2·6H2O and 2-methylimidazole and dissolve them in methanol to obtain a coating liquid, add activated carbon to the coating liquid, stir at room temperature for 28 hours, and then collect by centrifugation to obtain ZIF-8@activated carbon core-shell particles; wherein the temperature of the concentrated nitric acid reflux is 82°C, the time is 3 hours, the amount ratio of the Zn(NO3)2·6H2O, 2-methylimidazole and methanol is 5.95g:6.5g:520mL, and the amount ratio of the activated carbon to the coating liquid is 10g:500mL.

[0037] ZIF-8@activated carbon core-shell particles were added to N-methylpyrrolidone, and additives were added to mix to obtain ZIF-8@activated carbon core-shell slurry; the slurry formula by mass fraction was: 45% ZIF-8@activated carbon core-shell particles, 12% polyvinylidene fluoride-hexafluoropropylene copolymer, 3% lithium bis(trifluoromethanesulfonyl)imide, 3% hydrophobic SiO2 nanospheres, 2% multi-walled carbon nanotubes and 35% N-methylpyrrolidone.

[0038] Then, Cr(NO3)3·9H2O, terephthalic acid and 2-aminoterephthalic acid were mixed (the mixing mass ratio was 1:0.4:0.1), and amino-modified MIL-101(Cr) was obtained by hydrothermal synthesis (first reacting at 150°C for 12 hours, then Soxhlet extraction with methanol for 42 hours, and finally vacuum activation at 150°C). The mixture was added to N-methylpyrrolidone, and auxiliary agents were added to obtain amino-modified MIL-101(Cr) slurry; the slurry formula by mass fraction was: 35% amino-modified MIL-101(Cr), 15% polyvinylidene fluoride-hexafluoropropylene copolymer, 3% lithium bis(trifluoromethanesulfonyl imide), 1.5% carbon black and 45.5% N-methylpyrrolidone.

[0039] S3, coating the surface of the conductive support skeleton with ZIF-8@activated carbon core-shell slurry and amino-modified MIL-101(Cr) slurry in sequence, with the wet film thickness of ZIF-8@activated carbon core-shell slurry being 100 μm and the wet film thickness of amino-modified MIL-101(Cr) slurry being 75 μm, and then vacuum drying and hot pressing, with the vacuum drying temperature being 75°C and the time being 2 h, and the hot pressing temperature being 115°C, the pressure being 10 MPa, and the time being 5 min, to finally obtain a gradient adsorption layer; S4, taking a mixed aqueous solution of MnSO4 and Na2SO4 with a concentration of 0.1 M as an electrodeposition solution, performing electrodeposition on the surface of the gradient adsorption layer to obtain a MnO2 nanowire array, the voltage of the electrodeposition being 0.8 V vs. Ag / AgCl, the time being 20 min, and the temperature being 25°C, then immersing the product in a 0.05 M NiCl2 solution for 5 min, blowing nitrogen after taking out, then performing nitridation treatment (reacting in an NH3 atmosphere at 400°C for 1 h) to obtain a MnO2-Ni3N heterojunction nanowire array, and finally performing atomic layer deposition (ALD) of a porous protective film on the surface of the array using trimethylaluminum and deionized water as alternating precursors, the temperature of the atomic layer deposition being 120°C, the number of cycles being 15 cycles, and the single-cycle growth rate being 0.11±0.01 nm / cycle, to obtain a catalytic conversion layer; S5, taking the product of step S4 to perform pre-expansion treatment and gas permeable membrane packaging, the pre-expansion treatment referring to placing the product in an autoclave, charging N2 to 0.5 MPa and maintaining the pressure for 1.1 h, and then releasing the pressure to normal pressure at a rate of 0.03 MPa / min, and the gas permeable membrane packaging referring to hot-pressing the product with an ePTFE film with a thickness of 50 μm and a pore size of 0.2±0.02 μm, the hot-pressing temperature being 145°C, the pressure being 0.5 MPa, and the time being 9 s, to obtain the gas absorption and enrichment material for the battery cell.

[0040] A bulge-preventing lithium battery, the battery cell of the bulge-preventing lithium battery comprising, in sequence, a positive current collector (15 μm thick aluminum foil), a positive electrode coating (using NCM622 ternary material as active material, conductive carbon black as conductive agent, and PVDF as binder), a separator (16 μm thick ceramic-coated PE-based film), a negative electrode coating (using artificial graphite as active material, conductive carbon black as conductive agent, and CMC / SBR as binder), a negative current collector (10 μm thick copper foil), and an electrolyte (1.1 mol / L LiPF6 dissolved in a mixed solvent with a volume ratio of EC:EMC=3:7), and the battery cell top sealing area being provided with the gas absorption and enrichment material for the battery cell.

[0041] Comparative Example 2 A method for preparing a gas absorption and enrichment material for a battery cell, the method steps comprising: S1. Boric acid and a graphene oxide dispersion with a mass concentration of 2.2% are taken, and the amount ratio of boric acid to graphene oxide dispersion is 0.5g:500mL. The mixture is ultrasonically mixed (frequency is 40kHz, time is 1.1h), hydrothermally reduced (temperature is 175℃, time is 6h) and freeze-dried (temperature is -45℃, time is 42h) to obtain a boron-doped graphene aerogel. Then, 0.1M LiOH and 0.03M H3PO4 are added to an ethanol solution with a mass concentration of 70% as a solvent and reacted to obtain a Li3PO4 precursor solution. The Li3PO4 precursor solution is deposited on the surface of the boron-doped graphene aerogel by an immersion pulling method at a pulling speed of 11mm / min. After the pulling is completed, the mixture is sintered at 300℃ under nitrogen protection for 1.1 to obtain a conductive support skeleton. S2. Prepare ZIF-8@activated carbon core-shell particles, specifically: take activated carbon and wash it to neutrality after refluxing with concentrated nitric acid, then take Zn(NO3)2·6H2O and 2-methylimidazole and dissolve them in methanol to obtain a coating liquid, add activated carbon to the coating liquid, stir at room temperature for 28 hours, and then collect by centrifugation to obtain ZIF-8@activated carbon core-shell particles; wherein the temperature of the concentrated nitric acid reflux is 82°C, the time is 3 hours, the amount ratio of the Zn(NO3)2·6H2O, 2-methylimidazole and methanol is 5.95g:6.5g:520mL, and the amount ratio of the activated carbon to the coating liquid is 10g:500mL.

[0042] ZIF-8@activated carbon core-shell particles were added to N-methylpyrrolidone, and additives were added to mix to obtain ZIF-8@activated carbon core-shell slurry; the slurry formula by mass fraction was: 45% ZIF-8@activated carbon core-shell particles, 12% polyvinylidene fluoride-hexafluoropropylene copolymer, 3% lithium bis(trifluoromethanesulfonyl)imide, 3% hydrophobic SiO2 nanospheres, 2% multi-walled carbon nanotubes and 35% N-methylpyrrolidone.

[0043] Then, Cr(NO3)3·9H2O, terephthalic acid and 2-aminoterephthalic acid were mixed (the mixing mass ratio was 1:0.4:0.1), and amino-modified MIL-101(Cr) was obtained by hydrothermal synthesis (first reacting at 150°C for 12 hours, then Soxhlet extraction with methanol for 42 hours, and finally vacuum activation at 150°C). The mixture was added to N-methylpyrrolidone, and auxiliary agents were added to obtain amino-modified MIL-101(Cr) slurry; the slurry formula by mass fraction was: 35% amino-modified MIL-101(Cr), 15% polyvinylidene fluoride-hexafluoropropylene copolymer, 3% lithium bis(trifluoromethanesulfonyl imide), 1.5% carbon black and 45.5% N-methylpyrrolidone.

[0044] S3, sequentially coating the surface of the conductive support skeleton with amino-modified MIL-101 (Cr) slurry and ZIF-8@activated carbon core-shell slurry, wherein the wet film thickness of the amino-modified MIL-101 (Cr) slurry is 75 μm, and the wet film thickness of the ZIF-8@activated carbon core-shell slurry is 100 μm, and then vacuum drying and hot pressing are performed, wherein the vacuum drying temperature is 75° C. and the time is 2 h, and the hot pressing temperature is 115° C., the pressure is 10 MPa, and the time is 5 min, to finally obtain a gradient adsorption layer; S4. A mixed aqueous solution of MnSO4 and Na2SO4 with a concentration of 0.1M was used as an electrodeposition solution, and an MnO2 nanowire array was obtained by electrodeposition on the surface of the gradient adsorption layer. The electrodeposition voltage was 0.8V vs. Ag / AgCl, the time was 20min, and the temperature was 25°C. It was then immersed in a NiCl2 solution with a concentration of 0.05M for 5min, taken out and purged with nitrogen, and then nitrided (reacted at 400°C in an NH3 atmosphere for 1h) to obtain a MnO2-Ni3N heterojunction nanoarray. Finally, trimethylaluminum and deionized water were used as alternating precursors to atomically layer deposit an ALD porous protective film on the array surface. The temperature of the atomic layer deposition was 120°C, the number of cycles was 15 cycles, and the single-cycle growth rate was 0.11±0.01nm / cycle to obtain a catalytic conversion layer. S5. The product of step S4 is pre-expanded and packaged with a breathable membrane. The pre-expansion treatment refers to placing the product in an autoclave, filling it with N2 to 0.5 MPa and maintaining the pressure for 1.1 hours, and then releasing the pressure to normal pressure at a rate of 0.03 MPa / min. The breathable membrane packaging refers to hot-pressing the product with an ePTFE membrane having a thickness of 50 μm and a pore size of 0.2±0.02 μm. The hot pressing temperature is 145°C, the pressure is 0.5 MPa, and the time is 9 seconds to obtain the battery cell gas absorption and enrichment material.

[0045] Disclosed is a bulge-proof lithium battery. The battery cell of the bulge-proof lithium battery comprises a positive electrode current collector (15μm thick aluminum foil), a positive electrode coating (using NCM622 ternary material as an active material, conductive carbon black as a conductive agent, and PVDF as a binder), a separator (16μm thick ceramic-coated PE base film), a negative electrode coating (using artificial graphite as an active material, conductive carbon black as a conductive agent, and CMC / SBR as a binder), a negative electrode current collector (10μm thick copper foil), and an electrolyte (1.1 mol / L LiPF6 dissolved in a mixed solvent with a volume ratio of EC:EMC=3:7). The battery cell top seal area is provided with the battery cell gas absorption and enrichment material.

[0046] Comparative Example 3 A method for preparing a gas absorption and enrichment material for a battery cell, the method comprising the following steps: S1. Boric acid and a graphene oxide dispersion with a mass concentration of 2.2% are taken, and the amount ratio of boric acid to graphene oxide dispersion is 0.5g:500mL. The mixture is ultrasonically mixed (frequency is 40kHz, time is 1.1h), hydrothermally reduced (temperature is 175℃, time is 6h) and freeze-dried (temperature is -45℃, time is 42h) to obtain a boron-doped graphene aerogel. Then, 0.1M LiOH and 0.03M H3PO4 are added to an ethanol solution with a mass concentration of 70% as a solvent and reacted to obtain a Li3PO4 precursor solution. The Li3PO4 precursor solution is deposited on the surface of the boron-doped graphene aerogel by an immersion pulling method at a pulling speed of 11mm / min. After the pulling is completed, the mixture is sintered at 300℃ under nitrogen protection for 1.1 to obtain a conductive support skeleton. S2. Prepare ZIF-8@activated carbon core-shell particles, specifically: take activated carbon and wash it to neutrality after refluxing with concentrated nitric acid, then take Zn(NO3)2·6H2O and 2-methylimidazole and dissolve them in methanol to obtain a coating liquid, add activated carbon to the coating liquid, stir at room temperature for 28 hours, and then collect by centrifugation to obtain ZIF-8@activated carbon core-shell particles; wherein the temperature of the concentrated nitric acid reflux is 82°C, the time is 3 hours, the amount ratio of the Zn(NO3)2·6H2O, 2-methylimidazole and methanol is 5.95g:6.5g:520mL, and the amount ratio of the activated carbon to the coating liquid is 10g:500mL.

[0047] ZIF-8@activated carbon core-shell particles were added to N-methylpyrrolidone, and additives were added to mix to obtain ZIF-8@activated carbon core-shell slurry; the slurry formula by mass fraction was: 45% ZIF-8@activated carbon core-shell particles, 12% polyvinylidene fluoride-hexafluoropropylene copolymer, 3% lithium bis(trifluoromethanesulfonyl)imide, 3% hydrophobic SiO2 nanospheres, 2% multi-walled carbon nanotubes and 35% N-methylpyrrolidone.

[0048] Then, Cr(NO3)3·9H2O, terephthalic acid and 2-aminoterephthalic acid were mixed (the mixing mass ratio was 1:0.4:0.1), and amino-modified MIL-101(Cr) was obtained by hydrothermal synthesis (first reacting at 150°C for 12 hours, then Soxhlet extraction with methanol for 42 hours, and finally vacuum activation at 150°C). The mixture was added to N-methylpyrrolidone, and auxiliary agents were added to obtain amino-modified MIL-101(Cr) slurry; the slurry formula by mass fraction was: 35% amino-modified MIL-101(Cr), 15% polyvinylidene fluoride-hexafluoropropylene copolymer, 3% lithium bis(trifluoromethanesulfonyl imide), 1.5% carbon black and 45.5% N-methylpyrrolidone.

[0049] S3, coating ZIF-8@activated carbon core-shell slurry and amino-modified MIL-101(Cr) slurry on the surface of the conductive support framework in turn, the wet film thickness of the coated ZIF-8@activated carbon core-shell slurry is 100 μm, the wet film thickness of the coated amino-modified MIL-101(Cr) slurry is 75 μm, then vacuum drying and hot pressing are performed, the temperature of the vacuum drying is 75℃, the time is 2 h, the temperature of the hot pressing is 115℃, the pressure is 10 MPa, and the time is 5 min, and finally a gradient adsorption layer is obtained; S4, taking a mixed aqueous solution of MnSO4 and Na2SO4 with a concentration of 0.1 M as an electrodeposition solution, performing electrodeposition on the surface of the gradient adsorption layer to obtain a MnO2 nanowire array, the voltage of the electrodeposition is 0.8 V vs. Ag / AgCl, the time is 20 min, and the temperature is 25℃, then immersing it in a NiCl2 solution with a concentration of 0.05 M for 5 min, taking it out and blowing nitrogen, and then performing nitridation treatment (reacting in an NH3 atmosphere at 400℃ for 1 h) to obtain a MnO2-Ni3N heterojunction nanowire array, thereby obtaining a catalytic conversion layer; S5, taking the product of step S4 to perform pre-expansion treatment and air-permeable membrane packaging, the pre-expansion treatment refers to placing the product in an autoclave, charging N2 to 0.5 MPa and maintaining the pressure for 1.1 h, and then releasing the pressure to normal pressure at a rate of 0.03 MPa / min, and the air-permeable membrane packaging refers to hot-pressing compounding the product with an ePTFE membrane with a thickness of 50 μm and a pore size of 0.2±0.02 μm, the hot-pressing temperature is 145℃, the pressure is 0.5 MPa, and the time is 9 s, thereby obtaining the cell gas absorption and enrichment material.

[0050] A bulge-preventing lithium battery, the cell of the bulge-preventing lithium battery comprises a positive electrode current collector (15 μm thick aluminum foil), a positive electrode coating (NCM622 ternary material as active material, conductive carbon black as conductive agent, and PVDF as binder), a separator (16 μm thick ceramic-coated PE-based film), a negative electrode coating (artificial graphite as active material, conductive carbon black as conductive agent, and CMC / SBR as binder), a negative electrode current collector (10 μm thick copper foil), and an electrolyte (1.1 mol / L LiPF6 dissolved in a mixed solvent with a volume ratio of EC:EMC=3:7), which are arranged in turn, and the cell top sealing area is provided with the cell gas absorption and enrichment material.

[0051] Comparative Example 4 A preparation method of a cell gas absorption and enrichment material, the method steps comprise: S1. Boric acid and a graphene oxide dispersion with a mass concentration of 2.2% are taken, and the amount ratio of boric acid to graphene oxide dispersion is 0.5g:500mL. The mixture is ultrasonically mixed (frequency is 40kHz, time is 1.1h), hydrothermally reduced (temperature is 175℃, time is 6h) and freeze-dried (temperature is -45℃, time is 42h) to obtain a boron-doped graphene aerogel. Then, 0.1M LiOH and 0.03M H3PO4 are added to an ethanol solution with a mass concentration of 70% as a solvent and reacted to obtain a Li3PO4 precursor solution. The Li3PO4 precursor solution is deposited on the surface of the boron-doped graphene aerogel by an immersion pulling method at a pulling speed of 11mm / min. After the pulling is completed, the mixture is sintered at 300℃ under nitrogen protection for 1.1 to obtain a conductive support skeleton. S2. Prepare ZIF-8@activated carbon core-shell particles, specifically: take activated carbon and wash it to neutrality after refluxing with concentrated nitric acid, then take Zn(NO3)2·6H2O and 2-methylimidazole and dissolve them in methanol to obtain a coating liquid, add activated carbon to the coating liquid, stir at room temperature for 28 hours, and then collect by centrifugation to obtain ZIF-8@activated carbon core-shell particles; wherein the temperature of the concentrated nitric acid reflux is 82°C, the time is 3 hours, the amount ratio of the Zn(NO3)2·6H2O, 2-methylimidazole and methanol is 5.95g:6.5g:520mL, and the amount ratio of the activated carbon to the coating liquid is 10g:500mL.

[0052] ZIF-8@activated carbon core-shell particles were added to N-methylpyrrolidone, and additives were added to mix to obtain ZIF-8@activated carbon core-shell slurry; the slurry formula by mass fraction was: 45% ZIF-8@activated carbon core-shell particles, 12% polyvinylidene fluoride-hexafluoropropylene copolymer, 3% lithium bis(trifluoromethanesulfonyl)imide, 3% hydrophobic SiO2 nanospheres, 2% multi-walled carbon nanotubes and 35% N-methylpyrrolidone.

[0053] Then, Cr(NO3)3·9H2O, terephthalic acid and 2-aminoterephthalic acid were mixed (the mixing mass ratio was 1:0.4:0.1), and amino-modified MIL-101(Cr) was obtained by hydrothermal synthesis (first reacting at 150°C for 12 hours, then Soxhlet extraction with methanol for 42 hours, and finally vacuum activation at 150°C). The mixture was added to N-methylpyrrolidone, and auxiliary agents were added to obtain amino-modified MIL-101(Cr) slurry; the slurry formula by mass fraction was: 35% amino-modified MIL-101(Cr), 15% polyvinylidene fluoride-hexafluoropropylene copolymer, 3% lithium bis(trifluoromethanesulfonyl imide), 1.5% carbon black and 45.5% N-methylpyrrolidone.

[0054] S3, coating the surface of the conductive support skeleton with ZIF-8@activated carbon core-shell slurry and amino-modified MIL-101(Cr) slurry in sequence, with the wet film thickness of ZIF-8@activated carbon core-shell slurry being 100 μm and the wet film thickness of amino-modified MIL-101(Cr) slurry being 75 μm, and then vacuum drying and hot pressing, with the vacuum drying temperature being 75°C and the time being 2 h, and the hot pressing temperature being 115°C, the pressure being 10 MPa, and the time being 5 min, to finally obtain a gradient adsorption layer; S4. Take the product of step S3 for pre-expansion treatment and breathable membrane packaging. The pre-expansion treatment refers to placing the product in an autoclave, filling N2 to 0.5 MPa and maintaining the pressure for 1.1 hours, and then releasing the pressure to normal pressure at a rate of 0.03 MPa / min. The breathable membrane packaging refers to hot-pressing the product with an ePTFE membrane with a thickness of 50 μm and a pore size of 0.2±0.02 μm. The hot pressing temperature is 145°C, the pressure is 0.5 MPa, and the time is 9 seconds to obtain the battery core gas absorption and enrichment material.

[0055] Disclosed is a bulge-proof lithium battery. The battery cell of the bulge-proof lithium battery comprises a positive electrode current collector (15μm thick aluminum foil), a positive electrode coating (using NCM622 ternary material as an active material, conductive carbon black as a conductive agent, and PVDF as a binder), a separator (16μm thick ceramic-coated PE base film), a negative electrode coating (using artificial graphite as an active material, conductive carbon black as a conductive agent, and CMC / SBR as a binder), a negative electrode current collector (10μm thick copper foil), and an electrolyte (1.1 mol / L LiPF6 dissolved in a mixed solvent with a volume ratio of EC:EMC=3:7). The battery cell top seal area is provided with the battery cell gas absorption and enrichment material.

[0056] Comparative Example 5 A method for preparing a gas absorption and enrichment material for a battery cell, the method comprising the following steps: S1. Boric acid and a graphene oxide dispersion with a mass concentration of 2.2% are taken, and the amount ratio of boric acid to graphene oxide dispersion is 0.5g:500mL. The mixture is ultrasonically mixed (frequency is 40kHz, time is 1.1h), hydrothermally reduced (temperature is 175℃, time is 6h) and freeze-dried (temperature is -45℃, time is 42h) to obtain a boron-doped graphene aerogel. Then, 0.1M LiOH and 0.03M H3PO4 are added to an ethanol solution with a mass concentration of 70% as a solvent and reacted to obtain a Li3PO4 precursor solution. The Li3PO4 precursor solution is deposited on the surface of the boron-doped graphene aerogel by an immersion pulling method at a pulling speed of 11mm / min. After the pulling is completed, the mixture is sintered at 300℃ under nitrogen protection for 1.1 to obtain a conductive support skeleton. S2, preparing ZIF-8@ activated carbon core-shell particles, specifically: taking activated carbon, refluxing with concentrated nitric acid, washing to neutral, then taking Zn(NO3)2·6H2O and 2-methylimidazole, dissolving with methanol to obtain a coating solution, adding activated carbon to the coating solution, stirring at room temperature for 28 h, and then centrifuging to collect ZIF-8@ activated carbon core-shell particles; wherein the refluxing temperature of the concentrated nitric acid is 82℃, the refluxing time is 3h, the amount ratio of Zn(NO3)2·6H2O, 2-methylimidazole and methanol is 5.95g:6.5g:520mL, and the amount ratio of the activated carbon to the coating solution is 10g:500mL.

[0057] The ZIF-8@ activated carbon core-shell particles are added to N-methylpyrrolidone, and an additive is added, and mixed to obtain ZIF-8@ activated carbon core-shell slurry; the slurry formulation by mass fraction is: ZIF-8@ activated carbon core-shell particles 45%, polyvinylidene-hexafluoropropylene copolymer 12%, lithium bis(trifluoromethanesulfonyl)imide 3%, hydrophobic SiO2 nanoballs 3%, multi-walled carbon nanotubes 2% and N-methylpyrrolidone 35%.

[0058] Cr(NO3)3·9H2O, terephthalic acid and 2-amino terephthalic acid are mixed (the mass ratio of the mixture is 1:0.4:0.1), and then hydrothermally synthesized (firstly, reacting at 150℃ for 12h, then methanol Soxhlet extraction for 42h, and finally vacuum activation at 150℃) to obtain amino-modified MIL-101(Cr), which is added to N-methylpyrrolidone, and an additive is added, and mixed to obtain amino-modified MIL-101(Cr) slurry; the slurry formulation by mass fraction is: amino-modified MIL-101(Cr) 35%, polyvinylidene-hexafluoropropylene copolymer 15%, lithium bis(trifluoromethanesulfonyl)imide 3%, carbon black 1.5% and N-methylpyrrolidone 45.5%.

[0059] S3, sequentially coating ZIF-8@ activated carbon core-shell slurry and amino-modified MIL-101(Cr) slurry on the surface of the conductive support framework, the wet film thickness of the ZIF-8@ activated carbon core-shell slurry is 100μm, the wet film thickness of the amino-modified MIL-101(Cr) slurry is 75μm, then vacuum drying and hot pressing, the vacuum drying temperature is 75℃, the time is 2h, the hot pressing temperature is 115℃, the pressure is 10MPa, and the time is 5min, and finally a gradient adsorption layer is obtained; S4. A mixed aqueous solution of MnSO4 and Na2SO4 with a concentration of 0.1M was used as an electrodeposition solution, and an MnO2 nanowire array was obtained by electrodeposition on the surface of the gradient adsorption layer. The electrodeposition voltage was 0.8V vs. Ag / AgCl, the time was 20min, and the temperature was 25°C. It was then immersed in a NiCl2 solution with a concentration of 0.05M for 5min, taken out and purged with nitrogen, and then nitrided (reacted at 400°C in an NH3 atmosphere for 1h) to obtain a MnO2-Ni3N heterojunction nanoarray. Finally, trimethylaluminum and deionized water were used as alternating precursors to atomically layer deposit an ALD porous protective film on the array surface. The temperature of the atomic layer deposition was 120°C, the number of cycles was 15 cycles, and the single-cycle growth rate was 0.11±0.01nm / cycle to obtain a catalytic conversion layer. S5. The product of step S4 is packaged with a breathable membrane. The breathable membrane packaging refers to hot pressing and compounding the product with an ePTFE membrane with a thickness of 50 μm and a pore size of 0.2±0.02 μm. The hot pressing temperature is 145° C., the pressure is 0.5 MPa, and the time is 9 s to obtain the battery core gas absorption and enrichment material.

[0060] Disclosed is a bulge-proof lithium battery. The battery cell of the bulge-proof lithium battery comprises a positive electrode current collector (15μm thick aluminum foil), a positive electrode coating (using NCM622 ternary material as an active material, conductive carbon black as a conductive agent, and PVDF as a binder), a separator (16μm thick ceramic-coated PE base film), a negative electrode coating (using artificial graphite as an active material, conductive carbon black as a conductive agent, and CMC / SBR as a binder), a negative electrode current collector (10μm thick copper foil), and an electrolyte (1.1 mol / L LiPF6 dissolved in a mixed solvent with a volume ratio of EC:EMC=3:7). The battery cell top seal area is provided with the battery cell gas absorption and enrichment material.

[0061] 2. Performance Testing (1) Gas adsorption test Samples of the gas absorption and enrichment materials for battery cells prepared in Examples 1-3 and Comparative Examples 1-5 were cut to the same dimensions (100 mm × 100 mm × 0.5 mm) and placed in a sealed glass desiccator along with the composite gas. A CO2 sensor and gas chromatograph were then used to measure the concentration of each gas within the desiccator at 20°C and atmospheric pressure. During the adsorption process, the pressure within the desiccator was monitored in real time, and the pressure was maintained constant by varying the desiccator volume. Finally, after 27 hours, the adsorption amount of each gas was measured.

[0062] The composition of the composite gas is shown in Table 1 below: Table 1: Composition of composite gases

[0063] (2) Battery stability test Take the anti-bulging lithium battery samples prepared in the above Examples 1-3 and Comparative Examples 1-5 respectively, and fully charge the batteries at 1C at 45°C, let them stand for 10 minutes, and then fully discharge them at 1C. The charge and discharge steps are repeated, and the capacity retention rate and volume expansion rate after 500 cycles are calculated according to the following formula.

[0064]

[0065]

[0066] 3. Results Analysis The results of the above gas adsorption test and battery stability test are statistically obtained in Table 2 and Table 3 below: Table 2: Gas adsorption test results

[0067] Table 3: Battery stability test results

[0068] It can be seen from Tables 2 and 3 above that Examples 1-3 of the present invention have certain adsorption activity for CO2, CO, H2, C2H4 and CH4. When applied to gas adsorption in battery cells, they can meet the use requirements under normal operating conditions. In terms of battery stability testing, the capacity retention rate after 500 cycles can be above 88.1%, and the volume expansion rate is less than 7.9%, which is also excellent.

[0069] Comparative Examples 1-5 are all single-factor adjustments based on Example 2, among which: in Comparative Example 1, no Li3PO4 nanolayer is deposited on the surface of the conductive support skeleton, and the adsorption amount of each gas does not change significantly, but the volume expansion rate increases to 15.1% compared with Example 2, and the capacity retention rate also decreases to 83.1%, which may be due to the influence of electrolyte penetration; in the gradient adsorption layer of Comparative Example 2, the coating order of the two adsorption layers is swapped, and the amino-modified MIL-101 (Cr) slurry is coated first, and then the ZIF-8@ activated carbon core-shell slurry is coated, resulting in a significant decrease in the adsorption amount of CO2, CO and C2H4, and the volume expansion rate increases to 12.4% compared with Example 2, and the capacity retention rate decreases to 83.1%. The retention rate also dropped to 85.3%; in Comparative Example 3, no ALD porous protective film was deposited on the surface of the catalytic conversion layer, resulting in a slight decrease in the adsorption amount of most gases. At the same time, the volume expansion rate increased to 85.8% compared with Example 2, and the capacity retention rate also dropped to 10.6%; in Comparative Example 4, the entire catalytic conversion layer was directly removed, resulting in a significant decrease in the adsorption amount of CO and H2. At the same time, the volume expansion rate increased to 14.8% compared with Example 2, and the capacity retention rate also dropped to 84.9%; in Comparative Example 5, the pre-expansion treatment process was omitted, and the adsorption amount of each gas did not change significantly, but the volume expansion rate increased to 22.7% compared with Example 2, and the capacity retention rate also dropped to 80.6%.

[0070] The above-described embodiments merely illustrate several implementations of the present invention. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that variations and improvements are possible without departing from the scope of the present invention, and all such variations and improvements fall within the scope of protection of the present invention.

Claims

1. A battery core gas absorption and enrichment material, characterized in that: The material is composed of a conductive support skeleton, a gradient adsorption layer coated on the surface of the conductive support skeleton, and a catalytic conversion layer deposited on the surface of the gradient adsorption layer, and is prepared after pre-expansion treatment and breathable membrane packaging; Wherein, the conductive support skeleton adopts boron-doped graphene aerogel with a Li3PO4 nanolayer deposited on the surface; The gradient adsorption layer includes a primary adsorption layer and a secondary adsorption layer coated sequentially from the inside to the outside, wherein the primary adsorption layer adopts ZIF-8@activated carbon core-shell slurry, and the secondary adsorption layer adopts amino-modified MIL-101(Cr) slurry; The catalytic conversion layer adopts a MnO2-Ni3N heterojunction nanoarray with an ALD porous protective film deposited on the surface.

2. A method for preparing the gas absorption and enrichment material for a battery cell as claimed in claim 1, characterized in that: The method steps include: S1. Boric acid and graphene oxide dispersion are ultrasonically mixed, hydrothermally reduced, and freeze-dried to obtain boron-doped graphene aerogel. LiOH and H3PO4 are added to an ethanol solution as a solvent and reacted to obtain a Li3PO4 precursor solution. The Li3PO4 precursor solution is deposited on the surface of the boron-doped graphene aerogel by an immersion-coating method to obtain a conductive support skeleton. S2, preparing ZIF-8@activated carbon core-shell particles, adding them to N-methylpyrrolidone, adding an auxiliary agent, and mixing to obtain ZIF-8@activated carbon core-shell slurry; then taking Cr(NO3)3·9H2O, terephthalic acid and 2-aminoterephthalic acid, mixing them through hydrothermal synthesis to obtain amino-modified MIL-101(Cr), adding them to N-methylpyrrolidone, adding an auxiliary agent, and mixing to obtain amino-modified MIL-101(Cr) slurry; S3, coating the surface of the conductive support skeleton with ZIF-8@activated carbon core-shell slurry and amino-modified MIL-101(Cr) slurry in sequence, followed by vacuum drying and hot pressing to obtain a gradient adsorption layer; S4, taking a mixed aqueous solution of MnSO4 and Na2SO4 as an electrodeposition solution, electrodepositing a MnO2 nanowire array on the surface of the gradient adsorption layer, then immersing it in a NiCl2 solution, taking it out and purging it with nitrogen, and then nitriding it to obtain a MnO2-Ni3N heterojunction nanoarray, and finally using trimethylaluminum and deionized water as alternating precursors to atomic layer deposit an ALD porous protective film on the array surface to obtain a catalytic conversion layer; S5. The product of step S4 is subjected to pre-expansion treatment and breathable film packaging to obtain the battery core gas absorption and enrichment material.

3. The method for preparing the battery core gas absorption and enrichment material according to claim 2, wherein: In step S1, the mass concentration of the graphene oxide dispersion is 2-2.5%, the amount ratio of boric acid to graphene oxide dispersion is 0.5g:450-550mL, the frequency of the ultrasonic mixing is 35-45kHz, the time is 1-1.2h, the temperature of the hydrothermal reduction is 170-180°C, the time is 5-8h, the temperature of the freeze-drying is -40 to -50°C, the time is 36-48h, the mass concentration of the ethanol solution is 65-75%, the added concentration of LiOH is 0.08-0.12M, and the added concentration of H3PO4 is 0.025-0.035M; The pulling speed of the immersion pulling method is 10-12 mm / min, and after the pulling is completed, the sintering is carried out at 295-305° C. for 1-1.2 hours under nitrogen protection.

4. The method for preparing the gas absorption and enrichment material for a battery cell according to claim 2, wherein: In step S2, the specific operation of preparing ZIF-8@activated carbon core-shell particles is as follows: taking activated carbon and washing it to neutrality after refluxing with concentrated nitric acid, then taking Zn(NO3)2·6H2O and 2-methylimidazole and dissolving them in methanol to obtain a coating solution, adding activated carbon to the coating solution, stirring at room temperature for 24-32 hours, and then centrifuging to obtain ZIF-8@activated carbon core-shell particles; The reflux temperature of the concentrated nitric acid is 80-85°C for 2.5-3.5 hours, the dosage ratio of Zn(NO3)2·6H2O, 2-methylimidazole and methanol is 5.95g:6.5g:500-550mL, and the dosage ratio of the activated carbon to the coating liquid is 10g:400-600mL.

5. The method for preparing the battery core gas absorption and enrichment material according to claim 2, characterized in that: In step S2, the mass ratio of Cr(NO3)3·9H2O, terephthalic acid and 2-aminoterephthalic acid is 1:0.4:0.1, and the hydrothermal synthesis refers to first reacting at 145-155°C for 10-14 hours, then Soxhlet extraction with methanol for 36-48 hours, and finally vacuum activation at 145-155°C.

6. The method for preparing the gas absorption and enrichment material for a battery cell according to claim 2, wherein: In step S2, the additives in the ZIF-8@activated carbon core-shell slurry include polyvinylidene fluoride-hexafluoropropylene copolymer, lithium bis(trifluoromethanesulfonyl imide), hydrophobic SiO2 nanospheres and multi-walled carbon nanotubes, and the mass proportions of each component are: ZIF-8@activated carbon core-shell particles 42-48%, polyvinylidene fluoride-hexafluoropropylene copolymer 10-15%, lithium bis(trifluoromethanesulfonyl imide) 2-4%, hydrophobic SiO2 nanospheres 2-4%, multi-walled carbon nanotubes 1-3% and N-methylpyrrolidone 32-38%; The additives in the amino-modified MIL-101 (Cr) slurry include polyvinylidene fluoride-hexafluoropropylene copolymer, lithium bis(trifluoromethanesulfonyl imide) and carbon black, and the mass proportion of each component is: amino-modified MIL-101 (Cr) 32-38%, polyvinylidene fluoride-hexafluoropropylene copolymer 12-18%, lithium bis(trifluoromethanesulfonyl imide) 2-5%, carbon black 1-2% and N-methylpyrrolidone 40-50%.

7. The method for preparing the gas absorption and enrichment material for a battery cell according to claim 2, wherein: In step S3, the wet film thickness of the ZIF-8@activated carbon core-shell slurry is 90-110 μm, the wet film thickness of the amino-modified MIL-101 (Cr) slurry is 70-80 μm, the vacuum drying temperature is 70-80 ° C, the time is 1.8-2.2 h, the hot pressing temperature is 110-120 ° C, the pressure is 8-12 MPa, and the time is 4-6 min.

8. The method for preparing the gas absorption and enrichment material for a battery cell according to claim 2, wherein: In step S4, the concentrations of MnSO4 and Na2SO4 are both 0.08-0.12M, the electrodeposition voltage is 0.8V vs. Ag / AgCl, the time is 20±2min, and the temperature is 25±1°C; The concentration of the NiCl2 solution is 0.04-0.06M, the immersion time is 4-6 minutes, and the nitriding treatment refers to the reaction at 398-402°C in an NH3 atmosphere for 0.8-1.2 hours; The temperature of the atomic layer deposition is 120±2° C., the number of cycles is 15 cycles, and the growth rate per cycle is 0.11±0.01 nm / cycle.

9. The method for preparing the battery core gas absorption and enrichment material according to claim 2, characterized in that: In step S5, the pre-expansion treatment refers to placing the product in an autoclave, filling it with N2 to 0.5±0.02MPa and maintaining the pressure for 1-1.2h, and then releasing the pressure to normal pressure at a rate of 0.02-0.04MPa / min. The breathable membrane packaging refers to hot pressing the product with an ePTFE membrane with a thickness of 45-55μm and a pore size of 0.2±0.02μm. The hot pressing temperature is 140-150℃, the pressure is 0.4-0.6MPa, and the time is 8-10s.

10. An anti-bulging lithium battery, characterized in that: The battery cell of the anti-bulging lithium battery includes a positive electrode current collector, a positive electrode coating, a separator, a negative electrode coating, a negative electrode current collector and an electrolyte arranged in sequence, and the battery cell top sealing area is provided with the battery cell gas absorption and enrichment material according to any one of claims 1 to 9.

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