CN114628637B - Preparation method of high-conductivity lithium iron phosphate positive plate - Google Patents
Preparation method of high-conductivity lithium iron phosphate positive plate Download PDFInfo
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Abstract
The invention relates to the technical field of lithium iron phosphate positive plates, and discloses a preparation method of a high-conductivity lithium iron phosphate positive plate, which comprises the following steps: siO is made of 2 Mixing nanospheres serving as templates with melamine in water, performing ultrasonic dispersion, and performing two-step high-temperature sintering; then etching the product in hydrofluoric acid solution to remove SiO 2 Obtaining porous hollow g-C 3 N 4 A nanosphere; porous hollow g-C 3 N 4 Mixing nanospheres and graphene in N-methyl pyrrolidone, adding polyethylene glycol diacrylate and a photoinitiator after ultrasonic oscillation dispersion, stirring, and performing ultraviolet light initiated polymerization in an inert atmosphere; and finally adding nano lithium iron phosphate for fully homogenizing, and coating the obtained mixed slurry on a carbon-coated aluminum foil to obtain the positive plate. The invention forms a complete conductive path by doping method, thereby improving conductivity; and the proportion of the size of the particles is high, so that gap filling is realized, the compaction density of the lithium iron phosphate material is improved, and the densification of the positive plate is realized.
Description
Technical Field
The invention relates to the technical field of lithium iron phosphate positive plates, in particular to a preparation method of a high-conductivity lithium iron phosphate positive plate.
Background
At present, domestic lithium ion battery anode materials are mainly concentrated in lithium manganate, ternary lithium and lithium iron phosphate, wherein the lithium iron phosphate has the advantages of good cycle stability, high safety, rich raw material sources, no toxic metal and the like, and is considered as one of the materials with the most development prospect in the existing anode materials. In recent years, lithium iron phosphate power batteries are favored by global lithium battery experts by the advantages of absolute safety, reliability, ultra-long cycle life, stable discharge platform and the like, and have rapidly developed. The lithium iron phosphate power battery can be said to completely solve the potential safety hazard problem of lithium cobalt oxide and lithium manganate batteries, and lead the industry of Chinese lithium batteries to move to a new era. Particularly, the lithium iron phosphate power battery 1C has excellent cycle performance, and compared with other traditional lithium ion batteries, the lithium iron phosphate power battery 1C has the discharge use time as long as 2000 times, and the capacity retention rate is not lower than 80 percent.
The requirements of the power battery on the multiplying power performance are higher and higher, so that the performance requirements of the lithium iron phosphate material are improved, the research of the lithium iron phosphate battery is mainly focused on improving the ion diffusion rate and the ion conductivity, and the specific surface area of the lithium iron phosphate is improved, and the ion conductivity and the electron conductivity of the lithium iron phosphate are improved by coating or doping. The Chinese patent publication No. CN109244462A discloses a preparation method of a high-conductivity lithium iron phosphate material, which adopts a two-step method to prepare a lithium iron phosphate/carbon composite material, and on one hand, a layer of carbohydrate-decomposed organic carbon source is coated on the surface of the lithium iron phosphate through primary sintering; on the other hand, a vapor deposition technology (CVD) is introduced through secondary sintering, and a layer of high-temperature cracking carbon with higher graphitization degree is coated on the surface of lithium iron phosphate/carbon in a vapor deposition mode in the sintering process, so that the lithium iron phosphate material with high conductivity and low internal resistance is finally prepared. The method adopts a coating method to improve the conductivity, but gaps exist among positive electrode particles formed by the coating method, a complete conductive path cannot be formed, the compaction density is low, and a good densification structure cannot be realized.
Disclosure of Invention
The invention aims to provide a preparation method of a high-conductivity lithium iron phosphate positive plate, which adopts a doping method to improve ion and electron conductivity, form a complete conductive path, improve conductivity and realize void filling so as to ensure higher compaction density.
The aim of the invention is achieved by the following technical scheme.
The invention provides a preparation method of a high-conductivity lithium iron phosphate positive plate, which comprises the following steps:
(1) SiO is made of 2 Mixing nanospheres serving as templates with melamine in water, performing ultrasonic dispersion, and performing two-step high-temperature sintering; then etching the product in hydrofluoric acid solution to remove SiO 2 Sequentially filtering, washing and drying to obtain porous hollow g-C 3 N 4 A nanosphere;
(2) Porous hollow g-C 3 N 4 Nanospheres and graphene in N-methylpyridineMixing the components in the pyrrolidone, adding polyethylene glycol diacrylate and a photoinitiator after ultrasonic oscillation dispersion, stirring, and performing ultraviolet light initiated polymerization in an inert atmosphere; and finally adding nano lithium iron phosphate for fully homogenizing, and coating the obtained mixed slurry on a carbon-coated aluminum foil to obtain the positive plate.
The invention uses SiO 2 The nanospheres are used as templates, melamine is used as a reactant, and the surfaces of the nanospheres are sintered at high temperature to obtain SiO with a core-shell structure 2 -g-C 3 N 4 A nanosphere. And sintering at high temperature in two steps to make g-C 3 N 4 The shell layer forms a porous structure, and then the SiO is removed by etching treatment in hydrofluoric acid solution 2 Obtaining porous hollow g-C 3 N 4 A nanosphere.
Polyethylene glycol diacrylate can be used as polymer solid electrolyte to improve the conductivity and energy density of the positive plate. g-C 3 N 4 The graphite carbon nitride is added to reduce the crystallinity of the polymer solid electrolyte, form a lithium ion transmission network in a polymer matrix and effectively improve the conductivity of lithium ions. The polymer chain is inserted into g-C 3 N 4 Porous hollow structure of nanosphere, while graphene can better adsorb g-C 3 N 4 With it being present in the polymer matrix. And the hydroxyl groups rich in the surface of the graphene have good affinity with polyethylene glycol diacrylate, so that a complete conductive path is formed, and the conductivity is improved. The interaction force among the three can lead the lamellar structure of the graphene to generate relative micro-movement along with the movement of a molecular chain when polyethylene glycol diacrylate is crosslinked and polymerized, increase the specific surface area, provide more containing spaces of subsequent nano lithium iron phosphate particles, improve the contact area of the anode material and a conductive path, and further realize high conductivity.
In addition, porous hollow g-C 3 N 4 The nanospheres and the nano lithium iron phosphate particles are nano particles with different particle sizes, and according to the particle size proportion of the particles with different sizes, gap filling is realized, so that the compaction density of the lithium iron phosphate material is further improved, the densification of the positive electrode slurry on the surface of the positive electrode plate is realized, and the capacity and the electrochemical performance of the battery are improved.
Preferably, in step (1), the SiO 2 The grain diameter of the nanospheres is 500-600 nm.
Selecting SiO with larger particle size 2 The nanospheres can form gap filling with nano lithium iron phosphate particles, and the compaction compactness of the positive plate is good. In addition, siO with the particle size 2 The nanospheres are used as templates, and the surface g-C is not affected 3 N 4 The adhesion compactness of the shell layer ensures the formation of regular porous hollow g-C 3 N 4 A nanosphere structure.
Preferably, in the step (1), the two-step high-temperature sintering is: sintering for 1-2 h at 500-580 ℃ at a heating rate of 1-3 ℃/min; cooling to room temperature, treating for 10-30 min by using a hydrofluoric acid solution spraying method, sintering for 2-4 h at 580-650 ℃ and heating up at a speed of 2-4 ℃/min.
The first step of sintering at high temperature is to convert melamine reactant into g-C 3 N 4 Cooling to room temperature and treating with hydrofluoric acid solution to remove SiO partially 2 The shell layer is made to form a partial hollow structure. When the partial hollow structure is sintered at a high temperature in the second step, larger mesopores can be formed due to the enlarged contact area, so that better entanglement can be formed through a high molecular chain, and the intermolecular binding property is improved.
Preferably, in step (1), the SiO 2 The mass ratio of the nanospheres to the melamine is 1:1.8 to 3; the time of the mixed ultrasonic dispersion is 1-2 h; the mass fraction of hydrofluoric acid in the hydrofluoric acid solution is 4-8%, and the treatment time is 7-9 h.
Preferably, in step (1), the porous hollow g-C 3 N 4 The average pore diameter of the nanospheres is 5-20 nm.
The porous hollow g-C formed by the invention 3 N 4 The pore diameter of the nanosphere is favorable for improving the specific surface area, forming a better penetrating structure with a high molecular chain, and not embedding nano lithium iron phosphate particles due to oversized mesopores, but is unfavorable for improving the battery capacity and exerting better conductivity.
Preferably, in step (2), the porous g-C 3 N 4 The mass ratio of the nanospheres to the graphene is 0.5-0.8: 1 to 1.3; the ultrasonic oscillation dispersion is that the ultrasonic is carried out for 30-70 min at 40-60 ℃ and the frequency is 100-120 kHz.
Preferably, in the step (2), the photoinitiator is 2, 2-dimethoxy-2-acetophenone; the mass ratio of the polyethylene glycol diacrylate to the photoinitiator is 1:0.3 to 0.6.
Preferably, in the step (2), the inert atmosphere is a nitrogen or argon atmosphere; the wavelength of the ultraviolet light is 365nm, and the intensity is 5-7 mW/cm 2 Exposing for 3-6 times, wherein the exposure time is 5-8 min each time.
The ultraviolet initiated polymerization has too short exposure time, insufficient activation of photoinitiator and the like, incomplete crosslinking reaction, too long exposure time, and excessive polymerization can cause the porous hollow g-C 3 N 4 Excessive coating of nanospheres is unfavorable for subsequent nano lithium iron phosphate and porous hollow g-C 3 N 4 Gaps formed among the nanospheres are filled, and the surface compactness of the positive plate is reduced.
Preferably, in the step (2), the particle size of the nano lithium iron phosphate is 50 to 100nm.
Preferably, in the step (2), the nano lithium iron phosphate accounts for 91.5-94.5% of the mass of the mixed slurry.
Compared with the prior art, the invention has the following beneficial effects:
(1) By doping porous hollow g-C 3 N 4 The nanospheres, the graphene and the polyethylene glycol diacrylate form a complete conductive path, so that the conductivity is improved;
(2) The lamellar structure of the graphene can undergo relative micro-movement along with the cross-linking polymerization of the molecular chain, so that the specific surface area is increased, and the high conductivity is further realized;
(3) Porous hollow g-C 3 N 4 The particle size ratio of the nanospheres to the particle size of the nano lithium iron phosphate particles is different, so that gap filling is realized, the compaction density of the lithium iron phosphate material is improved, and the densification of the positive plate is realized.
Detailed Description
The technical scheme of the present invention is described below by using specific examples, but the scope of the present invention is not limited thereto:
general examples
The preparation method of the high-conductivity lithium iron phosphate positive plate comprises the following steps:
(1) SiO with particle diameter of 500-600 nm 2 Mixing nanospheres as templates with melamine in water, and SiO 2 The mass ratio of the nanospheres to the melamine is 1:1.8 to 3, after ultrasonic dispersion for 1 to 2 hours, performing two-step high-temperature sintering, and sintering for 1 to 2 hours at 500 to 580 ℃ at a heating rate of 1 to 3 ℃/min; cooling to room temperature, treating for 10-30 min by using a hydrofluoric acid solution spray method with the mass fraction of 4-8%, and sintering for 2-4 h at 580-650 ℃ with the temperature rising speed of 2-4 ℃/min; etching the product in 4-8 wt% hydrofluoric acid solution for 7-9 hr to eliminate SiO 2 Sequentially filtering, washing and drying to obtain porous hollow g-C 3 N 4 The average pore diameter of the nanospheres is 5-20 nm;
(2) The mass ratio is 0.5-0.8: 1 to 1.3 porous hollow g-C 3 N 4 Mixing nanospheres and graphene in N-methyl pyrrolidone, and adding the mixture into the mixture at the temperature of 40-60 ℃ and the frequency of 100-120 kHz after ultrasonic oscillation dispersion for 30-70 min, wherein the mass ratio is 1:0.3 to 0.6 of polyethylene glycol diacrylate and 2, 2-dimethoxy-2-acetophenone, and then stirring, and carrying out photoinitiated polymerization under nitrogen or argon atmosphere by using ultraviolet light with the wavelength of 365nm, wherein the intensity of the ultraviolet light is 5 to 7mW/cm 2 Exposing for 3-6 times, wherein the exposure time is 5-8 min each time; and finally, adding nano lithium iron phosphate with the particle size of 50-100 nm, fully homogenizing, and coating the obtained mixed slurry with the mass fraction of 91.5-94.5% on a carbon-coated aluminum foil to obtain the positive plate.
Example 1
The preparation method of the high-conductivity lithium iron phosphate positive plate comprises the following steps:
(1) SiO with particle diameter of 580nm 2 Mixing nanospheres as templates with melamine in water, and SiO 2 The mass ratio of the nanospheres to the melamine is 1:2.2, after ultrasonic dispersion for 1h, performing two-step high-temperature sintering, and sintering at 550 DEG CJunction for 1.5 hours, wherein the heating rate is 1 ℃/min; cooling to room temperature, treating for 20min by using a hydrofluoric acid solution spray method with the mass fraction of 6%, and sintering for 3h at 630 ℃ with the heating rate of 3 ℃/min; etching the product in hydrofluoric acid solution with mass fraction of 6% for 8h to remove SiO 2 Sequentially filtering, washing and drying to obtain porous hollow g-C 3 N 4 The average pore diameter of the nanospheres is 17nm;
(2) The mass ratio is 0.6:1.1 porous hollow g-C 3 N 4 Mixing nanospheres and graphene in N-methylpyrrolidone, performing ultrasonic oscillation dispersion for 45min at 55 ℃ and 100kHz, and adding the mixture into the mixture according to the mass ratio of 1:0.45 polyethylene glycol diacrylate and 2, 2-dimethoxy-2-acetophenone, stirring, and photo-initiation polymerizing under nitrogen atmosphere with 365nm ultraviolet light with intensity of 6mW/cm 2 Exposing for 5 times, wherein the exposure time is 5min each time; and finally, adding nano lithium iron phosphate with the particle size of 75nm, fully homogenizing, and coating the nano lithium iron phosphate with the mass fraction of 93% on a carbon-coated aluminum foil to obtain the positive plate.
Example 2
The preparation method of the high-conductivity lithium iron phosphate positive plate comprises the following steps:
(1) SiO with particle diameter of 530nm 2 Mixing nanospheres as templates with melamine in water, and SiO 2 The mass ratio of the nanospheres to the melamine is 1:1.8, after ultrasonic dispersion for 1h, performing two-step high-temperature sintering, wherein the sintering is performed for 1h at 520 ℃ before the heating speed is 2 ℃/min; cooling to room temperature, treating for 20min by using a hydrofluoric acid solution spray method with the mass fraction of 5%, and sintering for 2h at 640 ℃ with the heating rate of 3 ℃/min; etching the product in hydrofluoric acid solution with mass fraction of 5% for 9h to remove SiO 2 Sequentially filtering, washing and drying to obtain porous hollow g-C 3 N 4 The average pore diameter of the nanospheres is 13nm;
(2) The mass ratio is 0.5:1.3 porous hollow g-C 3 N 4 Mixing nanospheres and graphene in N-methylpyrrolidone, dispersing at 60deg.C under 100kHz for 70min under ultrasonic vibration, and adding massThe ratio is 1:0.4 polyethylene glycol diacrylate and 2, 2-dimethoxy-2-acetophenone, stirring, and photo-initiation polymerizing under nitrogen atmosphere with 365nm ultraviolet light with 5mW/cm intensity 2 Exposing for 6 times, wherein the exposure time is 5min each time; and finally, adding nano lithium iron phosphate with the particle size of 60nm, fully homogenizing, and coating the obtained mixed slurry with the mass fraction of 93.5% of nano lithium iron phosphate on a carbon-coated aluminum foil to obtain the positive plate.
Example 3
The preparation method of the high-conductivity lithium iron phosphate positive plate comprises the following steps:
(1) SiO with particle diameter of 560nm 2 Mixing nanospheres as templates with melamine in water, and SiO 2 The mass ratio of the nanospheres to the melamine is 1:2.6, after ultrasonic dispersion for 2 hours, performing two-step high-temperature sintering, and sintering for 1 hour at 580 ℃ before heating at a speed of 2 ℃/min; cooling to room temperature, treating for 15min by using a hydrofluoric acid solution spray method with the mass fraction of 8%, and sintering for 3h at 650 ℃ with the heating rate of 2 ℃/min; etching the product in 8% hydrofluoric acid solution for 7 hr to remove SiO 2 Sequentially filtering, washing and drying to obtain porous hollow g-C 3 N 4 The average pore diameter of the nanospheres is 16nm;
(2) The mass ratio is 0.8:1.1 porous hollow g-C 3 N 4 Mixing nanospheres and graphene in N-methylpyrrolidone, performing ultrasonic oscillation dispersion for 50min at 55 ℃ and 115kHz, and adding the mixture into the mixture according to the mass ratio of 1:0.3 polyethylene glycol diacrylate and 2, 2-dimethoxy-2-acetophenone, stirring, and photo-initiation polymerizing under nitrogen atmosphere with ultraviolet light with wavelength of 365nm and intensity of 7mW/cm 2 Exposing for 5 times, wherein the exposure time is 7min each time; and finally, adding nano lithium iron phosphate with the particle size of 75nm, fully homogenizing, and coating the obtained mixed slurry with the mass fraction of the nano lithium iron phosphate of 92.5% on a carbon-coated aluminum foil to obtain the positive plate.
Comparative example 1
The difference from example 1 is that: no porous hollow g-C was added 3 N 4 A nanosphere.
The specific preparation method comprises the following steps:
mixing graphene in N-methylpyrrolidone, performing ultrasonic oscillation dispersion for 45min at 55 ℃ and 100kHz, and adding the graphene into the mixture according to the mass ratio of 1:0.45 polyethylene glycol diacrylate and 2, 2-dimethoxy-2-acetophenone, stirring, and photo-initiation polymerizing under nitrogen atmosphere with 365nm ultraviolet light with intensity of 6mW/cm 2 Exposing for 5 times, wherein the exposure time is 5min each time; and finally, adding nano lithium iron phosphate with the particle size of 75nm, fully homogenizing, and coating the nano lithium iron phosphate with the mass fraction of 93% on a carbon-coated aluminum foil to obtain the positive plate.
Comparative example 2
The difference from example 1 is that: in step (1), siO 2 The particle size of the nanospheres was 300nm.
The specific preparation method comprises the following steps:
(1) SiO with particle diameter of 300nm 2 Mixing nanospheres as templates with melamine in water, and SiO 2 The mass ratio of the nanospheres to the melamine is 1:2.2, after ultrasonic dispersion for 1h, performing two-step high-temperature sintering, wherein the sintering is performed for 1.5h at 550 ℃ and the heating rate is 1 ℃/min; cooling to room temperature, treating for 20min by using a hydrofluoric acid solution spray method with the mass fraction of 6%, and sintering for 3h at 630 ℃ with the heating rate of 3 ℃/min; etching the product in hydrofluoric acid solution with mass fraction of 6% for 8h to remove SiO 2 Sequentially filtering, washing and drying to obtain porous hollow g-C 3 N 4 The average pore diameter of the nanospheres is 14nm;
(2) The mass ratio is 0.6:1.1 porous hollow g-C 3 N 4 Mixing nanospheres and graphene in N-methylpyrrolidone, performing ultrasonic oscillation dispersion for 45min at 55 ℃ and 100kHz, and adding the mixture into the mixture according to the mass ratio of 1:0.45 polyethylene glycol diacrylate and 2, 2-dimethoxy-2-acetophenone, stirring, and photo-initiation polymerizing under nitrogen atmosphere with 365nm ultraviolet light with intensity of 6mW/cm 2 Exposing for 5 times, wherein the exposure time is 5min each time; finally adding nano lithium iron phosphate with the particle size of 75nm for fully homogenizing to obtainThe mass fraction of nano lithium iron phosphate in the obtained mixed slurry is 93%, and the nano lithium iron phosphate is coated on a carbon-coated aluminum foil to obtain the positive plate.
Comparative example 3
The difference from example 1 is that: in step (1), siO 2 The particle size of the nanospheres is 700nm.
The specific preparation method comprises the following steps:
(1) SiO with particle diameter of 700nm 2 Mixing nanospheres as templates with melamine in water, and SiO 2 The mass ratio of the nanospheres to the melamine is 1:2.2, after ultrasonic dispersion for 1h, performing two-step high-temperature sintering, wherein the sintering is performed for 1.5h at 550 ℃ and the heating rate is 1 ℃/min; cooling to room temperature, treating for 20min by using a hydrofluoric acid solution spray method with the mass fraction of 6%, and sintering for 3h at 630 ℃ with the heating rate of 3 ℃/min; etching the product in hydrofluoric acid solution with mass fraction of 6% for 8h to remove SiO 2 Sequentially filtering, washing and drying to obtain porous hollow g-C 3 N 4 The average pore diameter of the nanospheres is 21nm, but the pore diameters are unevenly distributed, and the collapse phenomenon of the hollow structure occurs;
(2) The mass ratio is 0.6:1.1 porous hollow g-C 3 N 4 Mixing nanospheres and graphene in N-methylpyrrolidone, performing ultrasonic oscillation dispersion for 45min at 55 ℃ and 100kHz, and adding the mixture into the mixture according to the mass ratio of 1:0.45 polyethylene glycol diacrylate and 2, 2-dimethoxy-2-acetophenone, stirring, and photo-initiation polymerizing under nitrogen atmosphere with 365nm ultraviolet light with intensity of 6mW/cm 2 Exposing for 5 times, wherein the exposure time is 5min each time; and finally, adding nano lithium iron phosphate with the particle size of 75nm, fully homogenizing, and coating the nano lithium iron phosphate with the mass fraction of 93% on a carbon-coated aluminum foil to obtain the positive plate.
Comparative example 4
The difference from example 1 is that: in the step (1), the two-step high-temperature sintering is changed into one-step high-temperature sintering.
The specific preparation method comprises the following steps:
(1) SiO with particle diameter of 580nm 2 Mixing nanospheres as templates with melamine in water, and SiO 2 The mass ratio of the nanospheres to the melamine is 1:2.2, after ultrasonic dispersion for 1h, performing one-step high-temperature sintering, and sintering at 550 ℃ for 3h, wherein the heating rate is 1 ℃/min; etching the product in hydrofluoric acid solution with mass fraction of 6% for 8h to remove SiO 2 Sequentially filtering, washing and drying to obtain microporous g-C 3 N 4 Nanospheres, and the etching treatment does not completely remove SiO 2 ；
(2) The mass ratio is 0.6:1.1 porous hollow g-C 3 N 4 Mixing nanospheres and graphene in N-methylpyrrolidone, performing ultrasonic oscillation dispersion for 45min at 55 ℃ and 100kHz, and adding the mixture into the mixture according to the mass ratio of 1:0.45 polyethylene glycol diacrylate and 2, 2-dimethoxy-2-acetophenone, stirring, and photo-initiation polymerizing under nitrogen atmosphere with 365nm ultraviolet light with intensity of 6mW/cm 2 Exposing for 5 times, wherein the exposure time is 5min each time; and finally, adding nano lithium iron phosphate with the particle size of 75nm, fully homogenizing, and coating the nano lithium iron phosphate with the mass fraction of 93% on a carbon-coated aluminum foil to obtain the positive plate.
Comparative example 5
The difference from example 1 is that: in the step (2), the exposure time of ultraviolet light initiated polymerization is 10min.
The specific preparation method comprises the following steps:
(1) SiO with particle diameter of 580nm 2 Mixing nanospheres as templates with melamine in water, and SiO 2 The mass ratio of the nanospheres to the melamine is 1:2.2, after ultrasonic dispersion for 1h, performing two-step high-temperature sintering, wherein the sintering is performed for 1.5h at 550 ℃ and the heating rate is 1 ℃/min; cooling to room temperature, treating for 20min by using a hydrofluoric acid solution spray method with the mass fraction of 6%, and sintering for 3h at 630 ℃ with the heating rate of 3 ℃/min; etching the product in hydrofluoric acid solution with mass fraction of 6% for 8h to remove SiO 2 Sequentially filtering, washing and drying to obtain porous hollow g-C 3 N 4 The average pore diameter of the nanospheres is 17nm;
(2) Will beThe mass ratio is 0.6:1.1 porous hollow g-C 3 N 4 Mixing nanospheres and graphene in N-methylpyrrolidone, performing ultrasonic oscillation dispersion for 45min at 55 ℃ and 100kHz, and adding the mixture into the mixture according to the mass ratio of 1:0.45 polyethylene glycol diacrylate and 2, 2-dimethoxy-2-acetophenone, stirring, and photo-initiation polymerizing under nitrogen atmosphere with 365nm ultraviolet light with intensity of 6mW/cm 2 Exposing for 5 times, wherein the exposure time is 10min each time; and finally, adding nano lithium iron phosphate with the particle size of 75nm, fully homogenizing, and coating the nano lithium iron phosphate with the mass fraction of 93% on a carbon-coated aluminum foil to obtain the positive plate.
Performance testing
The positive plate prepared by the groups is used as a battery positive electrode, the negative electrode slurry obtained by mixing 96wt% of graphite, 2wt% of carbon nano tube and 2wt% of CMC is coated on a carbon-coated aluminum foil to prepare the negative plate, and the negative plate is used as a battery negative electrode. And placing a diaphragm between the positive plate and the negative plate, winding to form a battery core of the high-rate lithium iron phosphate battery, packaging the battery core into a shell, and injecting liquid to form the lithium iron phosphate battery. The compacted density of each set of positive plates and the conductivity of the battery were tested separately.
Table 1 results of Performance test of groups
| Example 1 | Example 2 | Example 3 | Comparative example 1 | Comparative example 2 | Comparative example 3 | Comparative example 4 | Comparative example 5 | |
| Conductivity (mS/cm) | 10.9 | 10.4 | 10.6 | 7.21 | 8.56 | 8.14 | 7.75 | 8.38 |
| Density of compaction (g/cm) 3 ) | 2.58 | 2.55 | 2.56 | 1.91 | 2.24 | 2.10 | 2.11 | 0.22 |
Specific results As shown in Table 1, in combination with examples 1 to 3 and comparative examples 1 to 5, the lithium iron phosphate positive electrode sheet prepared according to the present invention has high conductivity and high compacted density mainly because of the porous hollow g-C by doping 3 N 4 The nanospheres, the graphene and the polyethylene glycol diacrylate form a complete conductive path, so that the conductivity is improved; the lamellar structure of the graphene can relatively occur along with the cross-linking polymerization of the molecular chainMicro-movement, increasing the specific surface area and further realizing high conductivity; porous hollow g-C 3 N 4 The particle size ratio of the nanospheres to the particle size of the nano lithium iron phosphate particles is different, so that gap filling is realized, the compaction density of the lithium iron phosphate material is improved, and the densification of the positive plate is realized. It is understood that the porous hollow g-C was not added in combination with example 1 and comparative example 1 3 N 4 The nanospheres will not form a complete conductive path and voids exist between the positive electrode particles, densification cannot be achieved, and the conductivity and the compacted density are significantly reduced.
In combination with example 1 and comparative examples 2 to 3, siO was found to be 2 The particle diameter of the nanospheres is smaller, the difference between the particle diameter of the nanospheres and the particle diameter of the nano lithium iron phosphate is smaller, the compaction and compactness are poorer, and the SiO is poor 2 The particle size of the nanospheres is larger, and the nanospheres cannot form good coating, g-C 3 N 4 The porous structure of the nanosphere is easy to collapse, and is not beneficial to improving conductivity and compactness. In combination with example 1 and comparative example 4, only microporous g-C was obtained by one-step high temperature sintering 3 N 4 Nanospheres, and the etching treatment does not completely remove SiO 2 The polymer chains cannot form a good interpenetration structure, the intermolecular binding property is poor, and a complete conductive path cannot be formed. In combination with example 1 and comparative example 5, the exposure time to ultraviolet light was too long, and excessive polymerization caused a reaction to porous hollow g-C 3 N 4 Excessive coating of nanospheres is unfavorable for subsequent nano lithium iron phosphate and porous hollow g-C 3 N 4 The voids formed between the nanospheres fill and form a better conductive path.
The foregoing description is only of the preferred embodiments of the present invention, and is not intended to limit the scope of the invention, but rather is intended to cover any equivalents of the structures disclosed herein or modifications in the equivalent processes, or any application of the structures disclosed herein, directly or indirectly, in other related arts.
Claims (10)
1. The preparation method of the high-conductivity lithium iron phosphate positive plate is characterized by comprising the following steps of:
(1) SiO is made of 2 Nanospheres as templates, and melamine in waterAfter mixing and ultrasonic dispersion, performing two-step high-temperature sintering; then etching the product in hydrofluoric acid solution to remove SiO 2 Sequentially filtering, washing and drying to obtain porous hollow g-C 3 N 4 A nanosphere;
(2) Porous hollow g-C 3 N 4 Mixing nanospheres and graphene in N-methyl pyrrolidone, adding polyethylene glycol diacrylate and a photoinitiator after ultrasonic oscillation dispersion, stirring, and performing ultraviolet light initiated polymerization in an inert atmosphere; and finally adding nano lithium iron phosphate for fully homogenizing, and coating the obtained mixed slurry on a carbon-coated aluminum foil to obtain the positive plate.
2. The method for preparing a high-conductivity lithium iron phosphate positive electrode sheet according to claim 1, wherein in the step (1), the SiO 2 The particle size of the nanospheres is 500-600 nm.
3. The method for preparing a high-conductivity lithium iron phosphate positive electrode sheet according to claim 2, wherein in the step (1), the two steps of high-temperature sintering are as follows: sintering for 1-2 hours at 500-580 ℃ at a heating rate of 1-3 ℃/min; cooling to room temperature, treating for 10-30 min by using a hydrofluoric acid solution spraying method, and sintering for 2-4 h at 580-650 ℃ with a heating rate of 2-4 ℃/min.
4. The method for preparing a high-conductivity lithium iron phosphate positive electrode sheet according to claim 3, wherein in the step (1), the SiO 2 The mass ratio of the nanospheres to the melamine is 1: 1.8-3; the time of the mixed ultrasonic dispersion is 1-2 hours; the mass fraction of hydrofluoric acid in the hydrofluoric acid solution is 4-8%, and the treatment time is 7-9 h.
5. The method for preparing a high-conductivity lithium iron phosphate positive electrode sheet according to claim 4, wherein in the step (1), the porous hollow g-C 3 N 4 The average pore diameter of the nanospheres is 5-20 nm.
6. As claimed inThe method for preparing a high-conductivity lithium iron phosphate positive plate according to claim 1 or 5, wherein in the step (2), the porous hollow g-C 3 N 4 The mass ratio of the nanospheres to the graphene is 0.5-0.8: 1-1.3; the ultrasonic oscillation dispersion is that the ultrasonic is carried out for 30-70 min at the temperature of 40-60 ℃ and the frequency is 100-120 kHz.
7. The method for preparing a lithium iron phosphate positive electrode sheet with high conductivity according to claim 6, wherein in the step (2), the photoinitiator is 2, 2-dimethoxy-2-acetophenone; the mass ratio of the polyethylene glycol diacrylate to the photoinitiator is 1:0.3 to 0.6.
8. The method for preparing a high-conductivity lithium iron phosphate positive electrode sheet according to claim 7, wherein in the step (2), the inert atmosphere is a nitrogen or argon atmosphere; the wavelength of the ultraviolet light is 365nm, and the intensity is 5-7 mW/cm 2 Exposing for 3-6 times, wherein the exposure time is 5-8 min each time.
9. The method for preparing a high-conductivity lithium iron phosphate positive plate according to claim 8, wherein in the step (2), the particle size of the nano lithium iron phosphate is 50-100 nm.
10. The method for preparing a high-conductivity lithium iron phosphate positive plate according to claim 9, wherein in the step (2), the mass fraction of the nano lithium iron phosphate in the mixed slurry is 91.5-94.5%.
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Citations (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102742047A (en) * | 2009-10-07 | 2012-10-17 | 美奥泰科公司 | Actinic and electron beam radiation curable electrode binders and electrodes incorporating same |
| JP2012209218A (en) * | 2011-03-30 | 2012-10-25 | Sekisui Chem Co Ltd | Method for manufacturing lithium ion secondary battery, and lithium ion secondary battery |
| CN104134801A (en) * | 2014-07-28 | 2014-11-05 | 北京万源工业有限公司 | Carbon nitride and graphene cladded lithium iron phosphate composite anode material and preparation method thereof |
| CN107204446A (en) * | 2017-05-27 | 2017-09-26 | 广东烛光新能源科技有限公司 | Anode material for lithium-ion batteries and preparation method thereof |
| CN109449431A (en) * | 2018-12-16 | 2019-03-08 | 成都其其小数科技有限公司 | A method of preparing lithium battery size tunable cobalt phosphate lithium composite positive pole |
| CN109687013A (en) * | 2018-12-27 | 2019-04-26 | 江西省汇亿新能源有限公司 | A kind of high magnification, high safety, long-life ferric phosphate lithium cell and preparation method thereof |
| CN110120514A (en) * | 2019-05-27 | 2019-08-13 | 燕山大学 | Three-dimensional porous Co-C3N4Preparation method |
| CN110429277A (en) * | 2019-06-28 | 2019-11-08 | 合肥国轩高科动力能源有限公司 | A kind of preparation method of the lithium iron phosphate positive material of high-pressure solid high rate capability |
| CN113380981A (en) * | 2020-02-25 | 2021-09-10 | 株式会社理光 | Electrode and electrochemical element |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105498821B (en) * | 2015-12-17 | 2018-06-12 | 苏州大学 | It is a kind of for composite material of catalytic degradation nitrogen oxides and its preparation method and application |
| US11239466B2 (en) * | 2018-01-09 | 2022-02-01 | Saudi Arabian Oil Company | Nanocomposite cathode materials for use in batteries |
| US10957910B2 (en) * | 2019-05-01 | 2021-03-23 | Global Graphene Group, Inc. | Particulates of conducting polymer network-protected cathode active material particles for lithium batteries |
-
2021
- 2021-12-15 CN CN202111535764.7A patent/CN114628637B/en active Active
Patent Citations (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102742047A (en) * | 2009-10-07 | 2012-10-17 | 美奥泰科公司 | Actinic and electron beam radiation curable electrode binders and electrodes incorporating same |
| JP2012209218A (en) * | 2011-03-30 | 2012-10-25 | Sekisui Chem Co Ltd | Method for manufacturing lithium ion secondary battery, and lithium ion secondary battery |
| CN104134801A (en) * | 2014-07-28 | 2014-11-05 | 北京万源工业有限公司 | Carbon nitride and graphene cladded lithium iron phosphate composite anode material and preparation method thereof |
| CN107204446A (en) * | 2017-05-27 | 2017-09-26 | 广东烛光新能源科技有限公司 | Anode material for lithium-ion batteries and preparation method thereof |
| CN109449431A (en) * | 2018-12-16 | 2019-03-08 | 成都其其小数科技有限公司 | A method of preparing lithium battery size tunable cobalt phosphate lithium composite positive pole |
| CN109687013A (en) * | 2018-12-27 | 2019-04-26 | 江西省汇亿新能源有限公司 | A kind of high magnification, high safety, long-life ferric phosphate lithium cell and preparation method thereof |
| CN110120514A (en) * | 2019-05-27 | 2019-08-13 | 燕山大学 | Three-dimensional porous Co-C3N4Preparation method |
| CN110429277A (en) * | 2019-06-28 | 2019-11-08 | 合肥国轩高科动力能源有限公司 | A kind of preparation method of the lithium iron phosphate positive material of high-pressure solid high rate capability |
| CN113380981A (en) * | 2020-02-25 | 2021-09-10 | 株式会社理光 | Electrode and electrochemical element |
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