High-capacity and high-energy-density lithium / carbon fluoride battery and preparation method thereof

Abstract

The invention discloses a high-capacity and high-energy-density lithium / carbon fluoride battery and a preparation method thereof, and relates to the technical field of lithium / carbon fluoride batteries. The active carbon with high specific surface is added into the positive electrode slurry, and the porous structure of the active carbon provides more lithium ion transmission channels, so that LiF accumulation is relieved, polarization is reduced, and the discharge capacity and the energy density of the lithium / carbon fluoride battery are improved; and by optimizing the battery process ratio, the prepared lithium / carbon fluoride battery has high thermal conductivity and uniform heat dissipation, the thermal runaway risk is reduced, and the battery safety is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of lithium / carbon fluoride batteries, in particular to a high-capacity and high-energy-density lithium / carbon fluoride battery and a preparation method thereof. BACKGROUND

[0002] With the rapid development of aerospace, traditional batteries such as lead-acid batteries and nickel-hydrogen batteries gradually cannot meet the new demands brought by new technologies, and the energy storage field urgently needs new batteries with high energy density, high power density and excellent safety; lithium / carbon fluoride battery (Li / CFx) is a lithium primary battery using metal lithium as the negative electrode and carbon fluoride as the positive electrode, which has the highest theoretical specific energy (about 2180 Wh / kg) among various lithium primary batteries and is one of the currently commercialized lithium primary batteries; in addition, the battery system also has the advantages of good safety, long storage life, wide working temperature range, stable discharge voltage and the like.

[0003] However, due to the poor conductivity of carbon fluoride material itself, the battery will be polarized during discharge, resulting in low discharge voltage, poor rate performance, serious discharge heating and other problems, and the fluorination process is complex and requires high equipment, resulting in high battery preparation cost, which hinders the large-scale use of Li / CFx primary batteries.

[0004] Therefore, in order to overcome the defects of lithium / carbon fluoride batteries and meet the demand for high specific energy batteries for civilian instruments and equipment, household intelligent electrical appliances and the like, it is of great significance to develop a high-capacity and high-energy-density lithium / carbon fluoride battery. SUMMARY

[0005] The present application aims to provide a high-capacity and high-energy-density lithium / carbon fluoride battery and a preparation method thereof, so as to improve the capacity and energy density of the lithium / carbon fluoride battery.

[0006] To achieve the above-mentioned purpose, the present application provides the following technical scheme: a preparation method of a high-capacity and high-energy-density lithium / carbon fluoride battery, comprising the following steps: S1: dispersing carbon fluoride, activated carbon, conductive agent 1, conductive agent 2 and binder in a solvent, stirring uniformly to obtain a positive electrode slurry; S2: uniformly coating the positive electrode slurry on the upper surface and the lower surface of an aluminum foil, vacuum drying to obtain a carbon fluoride electrode, rolling and die cutting to obtain an electrode sheet, and welding a lead-out strip at the blank part of the electrode sheet to obtain a positive electrode sheet; S3: taking a lithium foil, die cutting to obtain a lithium foil sheet, and pressing a nickel strip on the lithium foil sheet to obtain a negative electrode sheet; S4: stacking the positive electrode sheet, a separator and the negative electrode sheet in sequence, winding and assembling to form a soft-pack lithium / carbon fluoride battery core, injecting an electrolyte, sealing to obtain a lithium / carbon fluoride battery.

[0007] Further, in S1, the mass ratio of carbon fluoride, activated carbon, conductive agent 1, conductive agent 2, and binder is (88-91):(1-3):(1-2):(1-2):(4-6). In S1, the solid content of the positive electrode slurry is 30-50%.

[0008] Further, in S1, the conductive agent 1 is one or more of Super-P (conductive carbon black), acetylene black, and Ketjen black. In S1, the conductive agent 2 is one or more of MWCNT (multi-walled carbon nanotube), SWCNT (single-walled carbon nanotube), VGCF (vapor-grown carbon fiber), and CNF (carbon nanofiber). In S1, the binder is one or a mixture of both of polyvinylidene fluoride and sodium alginate. In S1, the solvent is N-methylpyrrolidone.

[0009] Further, in S2, the aluminum foil has a thickness of 10-30 μm. In S1, the areal density of the carbon fluoride electrode is 200-260 g / m 2 .

[0010] Further, in S2, the carbon fluoride electrode has a rolled thickness of 0.15-0.16 mm.

[0011] Further, in S2, the process conditions for vacuum drying are a temperature of 100-120°C and a time of 3-4 h.

[0012] Further, in S3, the lithium foil has a thickness of 50-500 μm.

[0013] Further, in S4, the separator is a ceramic separator having a thickness of 14-16 μm.

[0014] Further, in S4, the electrolyte includes an electrolyte, a solvent, and an additive. The electrolyte is one or a mixture of both of LiBF4 (lithium tetrafluoroborate) and LiPF6 (lithium hexafluorophosphate). The solvent is a mixture of two or more of DEC (diethyl carbonate), EC (ethylene carbonate), EMC (ethyl methyl carbonate), and PC (propylene carbonate). The additive is one or a mixture of more than one of VC (vinylene carbonate), PS (propane sulfone), and FEC (fluoroethylene carbonate).

[0015] In the above technical solution, by adding high specific surface activated carbon in the positive electrode slurry, its porous structure provides more lithium ion transmission channels, relieves LiF accumulation, reduces polarization, and improves the discharge capacity and energy density of the lithium / carbon fluoride battery; by optimizing the process ratio of the battery, the prepared lithium / carbon fluoride battery has high thermal conductivity, uniform heat dissipation, reduces the risk of thermal runaway, and improves the safety of the battery.

[0016] Further, the polyvinylidene fluoride is modified, and the specific process is as follows: Step 1: Mix hydrated copper acetate, nickel acetate tetrahydrate, pyrazole dicarboxylic acid and N,N-dimethylamide aqueous solution, ultrasonic treatment, then heat reaction, cool, centrifuge, and wash 4-6 times to obtain a bimetallic organic framework; Step 2: Mix 60-70% of the mass component of the bimetallic organic framework and N,N-dimethylamide, ultrasonic treatment to form a suspension, stand, remove the precipitate from the suspension, and mix with polyvinylidene fluoride, heat reaction, cool, electrospinning, dry, ball milling, add the remaining mass component of the bimetallic organic framework, and continue ball milling to obtain modified polyvinylidene fluoride.

[0017] Further, in step 1, the mass ratio of hydrated copper acetate, nickel acetate tetrahydrate, pyrazole dicarboxylic acid and N,N-dimethylamide aqueous solution is 1:1:(1.5-2.5):(15-20); The N,N-dimethylamide aqueous solution is obtained by mixing N,N-dimethylamide and deionized water in a volume ratio of 1:1.

[0018] Further, in step 1, the ultrasonic treatment process conditions are: frequency 30-40 kHz, time 25-35 min; In step 1, the heating reaction process conditions are: temperature 75-85℃, time 10-12h; In step 1, the centrifugation process conditions are: speed 9000-12000r / min, time 10-15min.

[0019] Further, in step 2, the ratio of bimetallic organic framework, N,N-dimethylamide and polyvinylidene fluoride is (0.4-0.8)g:(15-25)mL:(2.5-4.5)g.

[0020] Further, in step 2, the ultrasonic treatment process conditions are: frequency 40-50 kHz, time 30-40 min; In step 2, the heating reaction process conditions are: temperature 200-220℃, time 1.5-3.5h.

[0021] Further, in step 2, the process condition of electrospinning is that the injection voltage is 12-16 kV, the injection distance is 12-16 cm, and the injection rate is 0.4-0.6 mL / h; In step 2, the process condition of drying is that the temperature is 100-120℃, and the time is 20-30 min. In step 2, the process condition of ball milling is that the rotation speed is 200-300 rpm, and the time is 2-3 h.

[0022] In the above technical solution, pyrazole dicarboxylic acid with rich coordination sites is used as a ligand, copper acetate hydrate and nickel acetate tetrahydrate provide metal nodes, and self-assembly is carried out under heating conditions to obtain a bimetallic conductive framework, which is then mixed with polyvinylidene fluoride, electrospun, and then ball milled to obtain modified polyvinylidene fluoride, which is used as a binder, thereby improving the surface energy of polyvinylidene fluoride, and the unsaturated metal sites and the unsaturated functional groups on the ligand enhance the chemical bonding with aluminum foil, further improving the peel strength and to some extent improving the discharge specific capacity and cycle performance stability of the prepared lithium / carbon fluoride battery. Through electrospinning, the bimetallic organic framework and polyvinylidene fluoride can be made into a three-dimensional interwoven composite, which improves the conductivity and reduces the interface resistance. In addition, the synergistic effect of copper and nickel elements produces a larger specific surface area and more active sites, greatly improving the charge transport performance and the energy storage performance of the prepared lithium / carbon fluoride battery.

[0023] Further, the ceramic separator is coated with a high-strength high-temperature-resistant coating, and the specific preparation process is as follows: The bimetallic organic framework, nitrogen-doped graphene, isopropanol aqueous solution, and binder are mixed and ultrasonically treated to obtain a high-strength high-temperature-resistant coating, which is uniformly coated on the surface of the ceramic separator and dried to obtain a high-strength high-temperature-resistant ceramic separator.

[0024] Further, the ratio of the bimetallic organic framework, nitrogen-doped graphene, isopropanol aqueous solution, and binder is 1 g:(0.45-0.65) g:(20-30) mL:(1.5-2.5) mL. The isopropanol aqueous solution is obtained by mixing isopropanol and deionized water at a volume ratio of 1:(2.5-3.5). The binder is sodium carboxymethyl cellulose.

[0025] Further, the process condition of ultrasonic treatment is that the frequency is 30-40 kHz, and the time is 50-60 min.

[0026] Further, the coating thickness of the coating is 8-12 μm. The process condition of drying is that the temperature is 65-75℃, and the time is 1.5-2.5 h.

[0027] In the above technical solution, the bimetallic organic framework has good high-temperature resistance, the traditional ceramic diaphragm may cause short circuit due to shrinkage at about 160 DEG C, the nitrogen-doped graphene also has good thermal stability, and can be used as a supporting framework to provide structural stability, further enhancing the mechanical strength and high-temperature resistance of the diaphragm, compared with ordinary graphene, the introduction of nitrogen atoms generates electrostatic repulsion between the layers, which can effectively prevent the stacking of graphene; the pore structure of the bimetallic organic framework is beneficial to the migration of lithium ions, and the nitrogen-doped graphene provides a channel for the rapid transfer of ions, and the synergistic effect of the two can improve the ionic conductivity; in addition, the diaphragm coated with the coating can inhibit the growth of lithium dendrites, reduce the risk of short circuit caused by lithium dendrites piercing the diaphragm, and further improve the cycle stability of the battery.

[0028] Compared with the prior art, the beneficial effects of the present application are: 1、The present application adds high specific surface activated carbon to the positive electrode slurry, uses its porous structure to provide more lithium ion transmission channels, relieves LiF accumulation, reduces polarization, improves the discharge capacity and energy density of the battery, and optimizes the process ratio of the battery, so that the prepared battery has high thermal conductivity, uniform heat dissipation, reduced risk of thermal runaway, and improved battery safety.

[0029] 2、The present application prepares a bimetallic conductive framework with copper and nickel as metal sites, mixes it with polyvinylidene fluoride, electrospins, and then ball mills to obtain modified polyvinylidene fluoride, which is used as a binder to improve the peel strength of the binder, electrospinning the bimetallic organic framework and polyvinylidene fluoride into a three-dimensional interwoven composite, giving the modified polyvinylidene fluoride good electrical conductivity, and the synergistic effect of copper and nickel elements produces a large specific surface area and a large number of active sites, greatly improving the charge transport performance and energy storage performance of the prepared lithium / carbon fluoride battery.

[0030] 3、The present application mixes the bimetallic conductive framework with nitrogen-doped graphene to prepare a high-strength high-temperature-resistant coating, which is uniformly coated on the surface of the ceramic diaphragm to obtain a high-strength high-temperature-resistant ceramic diaphragm; the bimetallic organic framework has good high-temperature resistance, and the nitrogen-doped graphene also has good thermal stability, and can be used as a supporting framework to provide structural stability, further enhancing the mechanical strength and high-temperature resistance of the diaphragm, the dispersibility of the nitrogen-doped graphene is better than that of ordinary graphene, and it is not easy to stack, the pore structure of the bimetallic organic framework is beneficial to the migration of lithium ions, and the nitrogen-doped graphene provides a channel for the rapid transfer of ions, and the synergistic effect of the two can improve the ionic conductivity; the diaphragm coated with the coating can inhibit the growth of lithium dendrites, reduce the risk of short circuit caused by lithium dendrites piercing the diaphragm, and further improve the cycle stability of the battery. BRIEF DESCRIPTION OF DRAWINGS

[0031] Figure 1A schematic diagram of discharge data of lithium / carbon fluoride batteries obtained in Examples 1-3 and Comparative Example 1 of the present application. DETAILED DESCRIPTION

[0032] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the protection scope of the present application.

[0033] In the following detailed description, Carbon fluoride, D50 particle size 5-15 μm, specific surface area 200-400 m2 / g; Activated carbon, D50 particle size 5-10 μm, specific surface area 1000-2000 m2 / g; Conductive agent 1 is Super-P, particle size 40 nm, specific surface area 60-65 m2 / g; Conductive agent 2 is SWCNT, tube diameter 8-20 nm, tube length 10-30 μm; Nitrogen-doped graphene, particle size 0.5-5 μm, thickness 0.8 nm; Preparation of electrolyte: LiPF6, LiBF4, DEC, EC, EMC, VC, PS are mixed in a mass ratio of 1:1:3:4:3:0.3:0.2, and stirred uniformly to obtain the electrolyte; The aqueous N,N-dimethylamide solution is obtained by mixing N,N-dimethylamide and deionized water in a volume ratio of 1:1.

[0034] Example 1: A preparation method of a high-capacity high-energy-density lithium / carbon fluoride battery, comprising the following steps: S1: Carbon fluoride, activated carbon, Super-P, SWCNT, and polyvinylidene fluoride are dispersed in N-methylpyrrolidone, and stirred uniformly to obtain a positive electrode slurry; S2: The positive electrode slurry is uniformly coated on the upper surface and the lower surface of an aluminum foil, vacuum dried to obtain a carbon fluoride electrode, rolled and die-cut to obtain an electrode sheet, and a lead-out strip is welded in the blank part of the electrode sheet to obtain a positive electrode sheet; S3: A lithium foil is die-cut to obtain a lithium foil sheet, and a nickel strip is pressed on the lithium foil sheet to obtain a negative electrode sheet; S4: The positive electrode sheet, a ceramic separator, and the negative electrode sheet are stacked in sequence, wound, assembled, and formed into a soft-pack lithium / carbon fluoride battery cell, electrolyte is injected, and the opening is sealed to obtain a lithium / carbon fluoride battery; in S1, the mass ratio of carbon fluoride, activated carbon, Super-P, SWCNT, and polyvinylidene fluoride is 90:1:2:2:5; in S1, the solid content of the positive electrode slurry is 50%; in S2, the thickness of the aluminum foil is 30 μm; and in S1, the area density of the carbon fluoride electrode is 230 g / m2.2 In S2, the rolling thickness of the carbon fluoride electrode is 0.15 mm; in S2, the process conditions of vacuum drying are: temperature 120℃, time 4h; in S3, the thickness of the lithium foil is 500μm; in S4, the thickness of the ceramic diaphragm is 16μm.

[0035] Embodiment 2: A preparation method of a high-capacity high-energy-density lithium / carbon fluoride battery, comprising the following steps: S1: dispersing carbon fluoride, activated carbon, Super-P, SWCNT, and polyvinylidene fluoride in N-methylpyrrolidone, stirring uniformly to obtain a positive electrode slurry; S2: uniformly coating the positive electrode slurry on the upper surface and the lower surface of an aluminum foil, vacuum drying to obtain a carbon fluoride electrode, rolling, die cutting to obtain an electrode sheet, welding a lead-out strip in the blank part of the electrode sheet to obtain a positive electrode sheet; S3: taking a lithium foil, die cutting to obtain a lithium foil sheet, pressing a nickel strip on the lithium foil sheet to obtain a negative electrode sheet; S4: stacking in the order of the positive electrode sheet, a ceramic diaphragm, and the negative electrode sheet, winding, assembling to form a soft-pack lithium / carbon fluoride battery cell, injecting an electrolyte, sealing to obtain a lithium / carbon fluoride battery; in S1, the mass ratio of carbon fluoride, activated carbon, Super-P, SWCNT, and polyvinylidene fluoride is 89:3:1.5:1.5:5; in S1, the solid content of the positive electrode slurry is 50%; in S2, the thickness of the aluminum foil is 20μm; in S1, the area density of the carbon fluoride electrode is 230g / m 2 ; in S2, the rolling thickness of the carbon fluoride electrode is 0.15 mm; in S2, the process conditions of vacuum drying are: temperature 120℃, time 4h; in S3, the thickness of the lithium foil is 300μm; in S4, the thickness of the ceramic diaphragm is 15μm.

[0036] Embodiment 3: A preparation method of a high-capacity high-energy-density lithium / carbon fluoride battery, comprising the following steps: S1: dispersing carbon fluoride, activated carbon, Super-P, SWCNT, and polyvinylidene fluoride in N-methylpyrrolidone, stirring uniformly to obtain a positive electrode slurry; S2: uniformly coating the positive electrode slurry on the upper surface and the lower surface of an aluminum foil, vacuum drying to obtain a carbon fluoride electrode, rolling, die cutting to obtain an electrode sheet, welding a lead-out strip in the blank part of the electrode sheet to obtain a positive electrode sheet; S3: taking a lithium foil, die cutting to obtain a lithium foil sheet, pressing a nickel strip on the lithium foil sheet to obtain a negative electrode sheet; S4: stacking in the order of the positive electrode sheet, a ceramic diaphragm, and the negative electrode sheet, winding, assembling to form a soft-pack lithium / carbon fluoride battery cell, injecting an electrolyte, sealing to obtain a lithium / carbon fluoride battery; in S1, the mass ratio of carbon fluoride, activated carbon, Super-P, SWCNT, and polyvinylidene fluoride is 90:2:2:2:4; in S1, the solid content of the positive electrode slurry is 50%; in S2, the thickness of the aluminum foil is 10μm; in S1, the area density of the carbon fluoride electrode is 230g / m 2In S2, the thickness of the fluorinated carbon electrode roll is 0.15 mm; in S2, the vacuum drying process conditions are: temperature 120℃, time 4h; in S3, the thickness of the lithium foil is 50 μm; in S4, the thickness of the ceramic diaphragm is 14 μm.

[0037] Example 4: A method for preparing a high-capacity, high-energy-density lithium / carbon fluoride battery, comprising the following steps: (1) Preparation of modified polyvinylidene fluoride: Step 1: Mix copper acetate hydrate, nickel acetate tetrahydrate, pyrazole dicarboxylic acid, and N,N-dimethylamide aqueous solution, sonicate, reheat to react, cool, centrifuge, and wash 6 times to obtain a bimetallic organic framework; Step 2: Mix 70% by mass of the bimetallic organic framework and N,N-dimethylamide, sonicate to form a suspension, let stand, take the suspension after removing the precipitate and mix with polyvinylidene fluoride, heat to react, cool, electrospin, dry, ball mill, add the remaining bimetallic organic framework, continue ball milling to obtain modified polyvinylidene fluoride; In Step 1, the mass ratio of copper acetate hydrate, nickel acetate tetrahydrate, pyrazole dicarboxylic acid, and N,N-dimethylamide aqueous solution is 1:1:2.5:20; In Step 1, the ultrasonic treatment process conditions are: frequency 40kHz, time 35min; In step 1, the heating reaction conditions are: temperature 85℃, time 12h; in step 1, the centrifugation conditions are: speed 12000r / min, time 15min; in step 2, the ratio of bimetallic organic framework, N,N-dimethylamide, and polyvinylidene fluoride is 0.8g:25mL:4.5g; in step 2, the ultrasonic treatment conditions are: frequency 50kHz, time 40min; in step 2, the heating reaction conditions are: temperature 220℃, time 3.5h; in step 2, the electrospinning conditions are: injection voltage 16kV, injection distance 16cm, injection rate 0.6mL / h; in step 2, the drying conditions are: temperature 120℃, time 30min; in step 2, the ball milling conditions are: speed 300rpm, time 3h. (2) Preparation of high-strength, high-temperature resistant ceramic diaphragms: A high-strength, high-temperature resistant coating was obtained by mixing a bimetallic organic framework, nitrogen-doped graphene, isopropanol aqueous solution, and sodium carboxymethyl cellulose, followed by ultrasonic treatment. This coating was then uniformly applied to the surface of a ceramic diaphragm and dried to obtain a high-strength, high-temperature resistant ceramic diaphragm. The ratio of the bimetallic organic framework, nitrogen-doped graphene, isopropanol aqueous solution, and binder was 1 g:0.65 g:30 mL:2.5 mL. The isopropanol aqueous solution was obtained by mixing isopropanol and deionized water at a volume ratio of 1:3.5. The ultrasonic treatment conditions were: frequency 40 kHz, time 60 min. The coating thickness was 12 μm. The drying conditions were: temperature 75 °C, time 2.5 h. (3) Preparation of lithium / carbon fluoride battery: S1: Disperse carbon fluoride, activated carbon, Super-P, SWCNT and modified polyvinylidene fluoride in N-methylpyrrolidone, stir uniformly to obtain a positive electrode slurry; S2: uniformly coat the positive electrode slurry on the upper and lower surfaces of an aluminum foil, vacuum dry to obtain a carbon fluoride electrode, roll and die cut to obtain an electrode sheet, weld a lead-out strip in the blank part of the electrode sheet to obtain a positive electrode sheet; S3: take a lithium foil, die cut to obtain a lithium foil sheet, press a nickel strip on the lithium foil sheet to obtain a negative electrode sheet; S4: stack the positive electrode sheet, high-strength high-temperature-resistant ceramic diaphragm and negative electrode sheet in order, wind and assemble to form a soft-pack lithium / carbon fluoride battery cell, inject electrolyte, seal to obtain a lithium / carbon fluoride battery; in S1, the mass ratio of carbon fluoride, activated carbon, Super-P, SWCNT and modified polyvinylidene fluoride is 90:1:2:2:5; in S1, the solid content of the positive electrode slurry is 50%; in S2, the thickness of the aluminum foil is 30 μm; in S1, the areal density of the carbon fluoride electrode is 230 g / m 2 ; in S2, the roll thickness of the carbon fluoride electrode is 0.15 mm; in S2, the process conditions for vacuum drying are: temperature 120℃, time 4h; in S3, the thickness of the lithium foil is 500 μm.

[0038] Example 5: A preparation method of a high-capacity high-energy-density lithium / carbon fluoride battery, comprising the following steps: (1) Preparation of modified polyvinylidene fluoride: Step 1: mixing copper acetate hydrate, nickel acetate tetrahydrate, pyrazole dicarboxylic acid and N,N-dimethylamide aqueous solution, ultrasonic treatment, heating reaction, cooling, centrifugation, washing 4-6 times to obtain a bimetallic organic framework; Step 2: mixing 65% mass component of the bimetallic organic framework and N,N-dimethylamide, ultrasonic treatment to form a suspension, standing, mixing the suspension from which the precipitate is removed with polyvinylidene fluoride, heating reaction, cooling, electrospinning, drying, ball milling, adding the remaining mass component of the bimetallic organic framework, and continuing ball milling to obtain modified polyvinylidene fluoride; in Step 1, the mass ratio of copper acetate hydrate, nickel acetate tetrahydrate, pyrazole dicarboxylic acid and N,N-dimethylamide aqueous solution is 1:1:2.0:18; in Step 1, the process conditions for ultrasonic treatment are: frequency 35 kHz, time 30 min; in Step 1, the process conditions for heating reaction are: temperature 80℃, time 11 h; in Step 1, the process conditions for centrifugation are: speed 10000 r / min, time 12 min; in Step 2, the ratio of the bimetallic organic framework, N,N-dimethylamide and polyvinylidene fluoride is 0.6 g:20 mL:3.5 g; in Step 2, the process conditions for ultrasonic treatment are: frequency 45 kHz, time 35 min; in Step 2, the process conditions for heating reaction are: temperature 210℃, time 2.5 h; in Step 2, the process conditions for electrospinning are: injection voltage 14 kV, injection distance 14 cm, injection rate 0.5 mL / h; in Step 2, the process conditions for drying are: temperature 110℃, time 25 min; in Step 2, the process conditions for ball milling are: speed 250 rpm, time 2.5 h; (2) Preparation of high-strength high-temperature-resistant ceramic separator: Mixing the bimetallic organic framework, nitrogen-doped graphene, isopropyl alcohol aqueous solution and carboxymethyl cellulose sodium, ultrasonic treatment to obtain a high-strength high-temperature-resistant coating, uniformly coating the coating on the surface of the ceramic separator, drying to obtain a high-strength high-temperature-resistant ceramic separator; the ratio of the bimetallic organic framework, nitrogen-doped graphene, isopropyl alcohol aqueous solution and binder is 1 g:0.55 g:25 mL:2.0 mL; the isopropyl alcohol aqueous solution is obtained by mixing isopropyl alcohol and deionized water at a volume ratio of 1:3.0; the process conditions for ultrasonic treatment are: frequency 35 kHz, time 55 min; the coating thickness of the coating is 10 μm; the process conditions for drying are: temperature 70℃, time 2.0 h; (3) Preparation of lithium / carbon fluoride battery: S1: carbon fluoride, activated carbon, Super-P, SWCNT, modified polyvinylidene fluoride are dispersed in N-methylpyrrolidone, stirred uniformly to obtain a positive electrode slurry; S2: the positive electrode slurry is uniformly coated on the upper surface and the lower surface of an aluminum foil, vacuum dried to obtain a carbon fluoride electrode, the electrode sheet is obtained through rolling and die cutting, and the lead-out strip is welded in the blank part of the electrode sheet to obtain a positive electrode sheet; S3: a lithium foil is taken, die cut to obtain a lithium foil sheet, and a nickel strip is pressed on the lithium foil sheet to obtain a negative electrode sheet; S4: the positive electrode sheet, a high-strength high-temperature-resistant ceramic diaphragm, and the negative electrode sheet are stacked in sequence, wound, assembled to form a soft-pack lithium / carbon fluoride battery cell, electrolyte is injected, sealed to obtain a lithium / carbon fluoride battery; in S1, the mass ratio of carbon fluoride, activated carbon, Super-P, SWCNT, and modified polyvinylidene fluoride is 90:1:2:2:5; in S1, the solid content of the positive electrode slurry is 50%; in S2, the thickness of the aluminum foil is 30 μm; in S1, the area density of the carbon fluoride electrode is 230 g / m 2 ; in S2, the rolling thickness of the carbon fluoride electrode is 0.15 mm; in S2, the process conditions of vacuum drying are: temperature 120℃, time 4h; in S3, the thickness of the lithium foil is 500 μm.

[0039] Example 6: A preparation method of a high-capacity high-energy-density lithium / carbon fluoride battery, comprising the following steps: (1) Preparation of modified polyvinylidene fluoride: Step 1: mixing copper acetate hydrate, nickel acetate tetrahydrate, pyrazole dicarboxylic acid and N,N-dimethylamide aqueous solution, ultrasonic treatment, heating reaction, cooling, centrifugation, washing 4-6 times to obtain a bimetallic organic framework; Step 2: mixing 60% mass component of the bimetallic organic framework and N,N-dimethylamide, ultrasonic treatment to form a suspension, standing, mixing the suspension from which the precipitate is removed with polyvinylidene fluoride, heating reaction, cooling, electrospinning, drying, ball milling, adding the remaining mass component of the bimetallic organic framework, and continuing ball milling to obtain modified polyvinylidene fluoride; in Step 1, the mass ratio of copper acetate hydrate, nickel acetate tetrahydrate, pyrazole dicarboxylic acid and N,N-dimethylamide aqueous solution is 1:1:1.5:15; in Step 1, the process conditions for ultrasonic treatment are: frequency 30 kHz, time 25 min; in Step 1, the process conditions for heating reaction are: temperature 75℃, time 10 h; in Step 1, the process conditions for centrifugation are: speed 9000 r / min, time 10 min; in Step 2, the ratio of the bimetallic organic framework, N,N-dimethylamide and polyvinylidene fluoride is 0.4 g:15 mL:2.5 g; in Step 2, the process conditions for ultrasonic treatment are: frequency 40 kHz, time 30 min; in Step 2, the process conditions for heating reaction are: temperature 200℃, time 1.5 h; in Step 2, the process conditions for electrospinning are: injection voltage 12 kV, injection distance 12 cm, injection rate 0.4 mL / h; in Step 2, the process conditions for drying are: temperature 100℃, time 20 min; in Step 2, the process conditions for ball milling are: speed 200 rpm, time 2 h; (2) Preparation of high-strength high-temperature-resistant ceramic separator: Mixing the bimetallic organic framework, nitrogen-doped graphene, isopropyl alcohol aqueous solution and carboxymethyl cellulose sodium, ultrasonic treatment to obtain a high-strength high-temperature-resistant coating, uniformly coating the coating on the surface of the ceramic separator, drying to obtain a high-strength high-temperature-resistant ceramic separator; the ratio of the bimetallic organic framework, nitrogen-doped graphene, isopropyl alcohol aqueous solution and binder is 1 g:0.45 g:20 mL:1.5 mL; the isopropyl alcohol aqueous solution is obtained by mixing isopropyl alcohol and deionized water at a volume ratio of 1:2.5; the process conditions for ultrasonic treatment are: frequency 30 kHz, time 50 min; the coating thickness of the coating is 8 μm; the process conditions for drying are: temperature 65℃, time 1.5 h; (3) Preparation of lithium / carbon fluoride battery: S1: carbon fluoride, activated carbon, Super-P, SWCNT, modified polyvinylidene fluoride are dispersed in N-methyl pyrrolidone, stirred uniformly to obtain a positive electrode slurry; S2: the positive electrode slurry is uniformly coated on the upper surface and the lower surface of an aluminum foil, vacuum dried to obtain a carbon fluoride electrode, subjected to rolling and die cutting to obtain an electrode sheet, and a lead-out strip is welded in the blank part of the electrode sheet to obtain a positive electrode sheet; S3: a lithium foil is taken and subjected to die cutting to obtain a lithium foil sheet, and a nickel strip is pressed on the lithium foil sheet to obtain a negative electrode sheet; S4: the positive electrode sheet, a high-strength high-temperature-resistant ceramic separator and the negative electrode sheet are stacked in sequence, wound and assembled to form a soft-pack lithium / carbon fluoride battery cell, electrolyte is injected, and the opening is sealed to obtain a lithium / carbon fluoride battery; in S1, the mass ratio of carbon fluoride, activated carbon, Super-P, SWCNT and modified polyvinylidene fluoride is 90:1:2:2:5; in S1, the solid content of the positive electrode slurry is 50%; in S2, the thickness of the aluminum foil is 30 μm; in S1, the area density of the carbon fluoride electrode is 230 g / m 2 ; in S2, the rolling thickness of the carbon fluoride electrode is 0.15 mm; in S2, the process conditions for vacuum drying are: temperature 120℃, time 4h; in S3, the thickness of the lithium foil is 500 μm.

[0040] Comparative Example 1: a preparation method of a high-capacity high-energy-density lithium / carbon fluoride battery, comprising the following steps: S1: carbon fluoride, Super-P, SWCNT, polyvinylidene fluoride are dispersed in N-methyl pyrrolidone, stirred uniformly to obtain a positive electrode slurry; S2: the positive electrode slurry is uniformly coated on the upper surface and the lower surface of an aluminum foil, vacuum dried to obtain a carbon fluoride electrode, subjected to rolling and die cutting to obtain an electrode sheet, and a lead-out strip is welded in the blank part of the electrode sheet to obtain a positive electrode sheet; S3: a lithium foil is taken and subjected to die cutting to obtain a lithium foil sheet, and a nickel strip is pressed on the lithium foil sheet to obtain a negative electrode sheet; S4: the positive electrode sheet, a ceramic separator and the negative electrode sheet are stacked in sequence, wound and assembled to form a soft-pack lithium / carbon fluoride battery cell, electrolyte is injected, and the opening is sealed to obtain a lithium / carbon fluoride battery; in S1, the mass ratio of carbon fluoride, Super-P, SWCNT and polyvinylidene fluoride is 91:2:2:5; in S1, the solid content of the positive electrode slurry is 50%; in S2, the thickness of the aluminum foil is 30 μm; in S1, the area density of the carbon fluoride electrode is 230 g / m 2 ; in S2, the rolling thickness of the carbon fluoride electrode is 0.15 mm; in S2, the process conditions for vacuum drying are: temperature 120℃, time 4h; in S3, the thickness of the lithium foil is 500 μm; in S4, the thickness of the ceramic separator is 16 μm.

[0041] Comparative Example 2: taking Example 4 as a comparison, a single-metal organic framework with copper as a metal site is used to replace the double-metal organic framework, and the mass ratio of hydrated copper acetate, pyrazole dicarboxylic acid and N,N-dimethylamide aqueous solution is controlled to be 1:2:20, and the rest of the conditions remain unchanged.

[0042] Comparative Example 3: In comparison with Example 4, no nitrogen-doped graphene was added in the high-strength high-temperature-resistant coating, and the rest of the conditions were unchanged.

[0043] Comparative Example 4: In comparison with Example 4, the bimetallic organic framework was replaced by a single-metal organic framework with copper as the metal site, the mass ratio of hydrated copper acetate, pyrazole dicarboxylic acid, and N,N-dimethylamide aqueous solution was controlled to be 1:2:20, and no nitrogen-doped graphene was added in the high-strength high-temperature-resistant coating, and the rest of the conditions were unchanged.

[0044] Experiment: The lithium / carbon fluoride batteries obtained in each example and comparative example were taken to detect their performance; Electrochemical test: At room temperature, the lithium / carbon fluoride battery was discharged at 0.1C, and the discharge cut-off voltage was 1.5V. The battery discharge capacity, discharge maximum temperature, discharge platform, and energy density were recorded; The separators obtained in each example and comparative example were taken to test their thermal shrinkage; Thermal shrinkage test: The obtained separator was cut into a 2x1cm sample, placed between two A4 papers, and placed in an oven with a temperature setting of 180℃. After drying for 1h, the sample was taken out, and the longitudinal and transverse dimensions were measured to calculate the shrinkage; Shrinkage = (length before drying-length after drying) / length before drying x 100%; ;

[0045] According to the data in the above table, the following conclusions can be drawn: Compared with Comparative Example 1, the battery electrochemical performance in Examples 1-3 is better, because in Comparative Example 1, no activated carbon is added, the lithium ion transmission channel is reduced, leading to LiF accumulation, reducing the overall performance of the battery; Compared with Examples 1 and Comparative Examples 2-4, the battery electrochemical performance in Examples 4-6 is better, and the heat resistance of the separator is better. The ceramic separator in Example 1 is not coated with a coating, Comparative Example 2 replaces the bimetallic organic framework with a single-metal organic framework with copper as the metal site, and Comparative Example 3 does not add nitrogen-doped graphene in the high-strength high-temperature-resistant coating. The performance of the battery and the separator prepared has decreased to varying degrees. According to Comparative Example 4, for the bimetallic organic framework and the high-strength high-temperature-resistant coating, the settings can promote the overall performance of the battery prepared in the application.

[0046] It will be apparent to those skilled in the art that the application is not limited to the details of the above-exemplified embodiments and that the present application can be implemented in other particular forms without departing from the spirit or essential characteristics of the present application. The embodiments should therefore be considered in all respects as illustrative and not restrictive, the scope of the application being indicated by the appended claims rather than by the above description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein. No reference signs in the claims should be considered as limiting the scope of the claims with respect to the figures of the patent document.

Claims

1. A method for preparing a high-capacity, high-energy-density lithium / carbon fluoride battery, characterized in that: Includes the following steps: S1: Disperse fluorinated carbon, activated carbon, conductive agent 1, conductive agent 2, and binder in a solvent and stir evenly to obtain a positive electrode slurry; S2: The positive electrode slurry is uniformly coated on the upper and lower surfaces of the aluminum foil, and vacuum dried to obtain a fluorinated carbon electrode. After rolling and die cutting, an electrode sheet is obtained. Lead strips are welded to the blank parts of the electrode sheet to obtain the positive electrode sheet. S3: Take lithium foil, perform die cutting to obtain lithium foil sheet, press nickel strip onto lithium foil sheet to obtain negative electrode sheet; S4: Stack, wind, and assemble the positive electrode, separator, and negative electrode in that order to form a soft-pack lithium / carbon fluoride cell. Inject electrolyte and seal to obtain a lithium / carbon fluoride battery.

2. The method for preparing a high-capacity, high-energy-density lithium / carbon fluoride battery according to claim 1, characterized in that: In S1, the mass ratio of fluorinated carbon, activated carbon, conductive agent 1, conductive agent 2, and binder is (88~91):(1~3):(1~2):(1~2):(4~6). In S1, the solid content of the positive electrode slurry is 30-50%.

3. The method for preparing a high-capacity, high-energy-density lithium / carbon fluoride battery according to claim 2, characterized in that: In S1, the areal density of the fluorinated carbon electrode is 200~260 g / m³. 2 .

4. The method for preparing a high-capacity, high-energy-density lithium / carbon fluoride battery according to claim 3, characterized in that: In S2, the thickness of the fluorinated carbon electrode roll is 0.15~0.16mm.

5. The method for preparing a high-capacity, high-energy-density lithium / carbon fluoride battery according to claim 4, characterized in that: In S1, conductive agent 1 is one or more of Super-P, acetylene black, and Ketjen black; In S1, conductive agent 2 is one or more of MWCNT, SWCNT, VGCF, and CNF; In S1, the binder is one or a mixture of two of polyvinylidene fluoride and sodium alginate. In S1, the solvent is N-methylpyrrolidone.

6. The method for preparing a high-capacity, high-energy-density lithium / carbon fluoride battery according to claim 5, characterized in that: In S2, the thickness of the aluminum foil is 10~30μm; In S3, the thickness of the lithium foil is 50~500μm; In S4, the diaphragm is a ceramic diaphragm with a thickness of 14~16μm.

7. The method for preparing a high-capacity, high-energy-density lithium / carbon fluoride battery according to claim 6, characterized in that: In S4, the electrolyte includes an electrolyte, a solvent, and an additive; The electrolyte is one or a mixture of LiBF4 and LiPF6; The solvent is a mixture of two or more of DEC, EC, EMC and PC; The additive is one or a mixture of VC, PS, and FEC.

8. The method for preparing a high-capacity, high-energy-density lithium / carbon fluoride battery according to claim 5, characterized in that: The polyvinylidene fluoride is modified, and the specific process is as follows: Step 1: Mix copper acetate hydrate, nickel acetate tetrahydrate, pyrazole dicarboxylic acid and N,N-dimethylamide aqueous solution, sonicate, then heat to react, cool, centrifuge, and wash 4-6 times to obtain bimetallic organic framework; Step 2: Take 60-70% by mass of the bimetallic organic framework and N,N-dimethylamide, mix them, sonicate to form a suspension, let stand, take the suspension after removing the precipitate and mix it with polyvinylidene fluoride, heat to react, cool, electrospin, dry, ball mill, add the remaining bimetallic organic framework, continue ball milling to obtain modified polyvinylidene fluoride.

9. The method for preparing a high-capacity, high-energy-density lithium / carbon fluoride battery according to claim 6, characterized in that: The ceramic diaphragm surface is coated with a high-strength, high-temperature resistant coating, and the specific preparation process is as follows: A high-strength, high-temperature resistant coating is obtained by mixing a bimetallic organic framework, nitrogen-doped graphene, isopropanol aqueous solution, and binder, followed by ultrasonic treatment. The coating is then uniformly applied to the surface of a ceramic diaphragm and dried to obtain a high-strength, high-temperature resistant ceramic diaphragm.

10. The method for preparing a high-capacity, high-energy-density lithium / carbon fluoride battery according to claim 8, characterized in that: In step 1, the mass ratio of copper acetate hydrate, nickel acetate tetrahydrate, pyrazole dicarboxylic acid, and N,N-dimethylamide aqueous solution is 1:1:(1.5~2.5):(15~20). The N,N-dimethylamide aqueous solution is obtained by mixing N,N-dimethylamide and deionized water at a volume ratio of 1:1.

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