CN110676435A - Method for preparing lithium battery cathode material by high-temperature molten salt constant-voltage electrolysis - Google Patents
Method for preparing lithium battery cathode material by high-temperature molten salt constant-voltage electrolysis Download PDFInfo
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- H01M4/00—Electrodes
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Abstract
A method for preparing a lithium battery cathode material by high-temperature molten salt constant-voltage electrolysis comprises the following steps: mixing coal powder and manganese dioxide to prepare a composite material; tabletting and then preparing a composite cathode with a current collector; preparing a foamed nickel cathode and an anode; mixing sodium carbonate and potassium carbonate, and heating in vacuum to obtain a mixed salt; suspending the composite cathode, the foamed nickel cathode and the anode above the mixed salt, sealing the reactor and introducing argon for circulation; melting the mixed salt to form molten salt, and continuously heating to 750 +/-5 ℃; carrying out constant-voltage pre-electrolysis; inserting the composite cathode into molten salt to perform constant-voltage electrolysis; and taking out the composite cathode, cooling, removing the molten salt on the surface, and drying to prepare the lithium battery cathode material. The method has the advantages of wide raw material source, environmental friendliness, low cost, simple operation and the like; the prepared battery cathode material has excellent performance and is beneficial to improving the surface structure of carbon.
Description
Technical Field
The invention belongs to the technical field of battery materials, and particularly relates to a method for preparing a lithium battery cathode material by high-temperature molten salt constant-voltage electrolysis.
Background
Batteries, which are devices that convert chemical energy into electrical energy, have been developed for over a hundred years as a traditional energy storage material; the battery has the advantages of stable output voltage and current and stable power supply for a long time as an energy source, has simple structure, convenient carrying, simple and easy charging and discharging operation, is not easily influenced by external climate and temperature, has stable and reliable performance, and plays a great role in modern social life.
At present, the negative electrode materials of the battery mainly comprise graphite, soft carbon (such as coke), hard carbon and the like, the negative electrode materials which are being explored comprise nitride, PAS, tin-based oxide, tin alloy, nano negative electrode materials and other intermetallic compounds, and the negative electrode materials which are most widely applied at present belong to carbon materials.
The lithium battery is one of the most widely used batteries at present, and the lithium battery has the problems of limited performance and high cost in use, and the performance of the negative electrode material of the lithium battery is urgently required to be improved on the premise of reducing the cost.
Disclosure of Invention
The invention aims to provide a method for preparing a lithium battery cathode material by high-temperature molten salt constant-voltage electrolysis, which is characterized in that coal powder is used as a carbon source to prepare a precursor, sodium carbonate/potassium carbonate mixed molten salt is used as a reaction medium, the performance of the material is changed by constant-potential electrolysis reaction, the lithium battery cathode material with excellent performance is prepared, the operation is simplified, and the cost is reduced.
The method of the invention is carried out according to the following steps:
1. grinding and ball-milling and mixing the coal powder and manganese dioxide to prepare a composite material; or grinding the coal powder and then ball-milling to prepare fine coal powder, adding the fine coal powder and ammonia water into a manganese salt solution, stirring and mixing uniformly, filtering to obtain a solid phase, and drying to remove water to prepare the composite material;
2. tabletting the composite material by a tablet machine to prepare a composite tablet material;
3. binding the composite pressing sheet material on a stainless steel wire current collector by using an iron wire to prepare a composite cathode; binding the foamed nickel on a stainless steel wire current collector by using an iron wire to prepare a foamed nickel cathode; connecting the nickel-based alloy with a stainless steel wire current collector to prepare an anode;
4. uniformly mixing sodium carbonate and potassium carbonate, placing the mixture into a crucible, then placing the crucible into a reactor, and heating the mixture to 300 +/-5 ℃ under the condition that the vacuum degree is less than or equal to 10Pa, and drying the mixture for at least 12 hours to obtain mixed salt; the mixed salt comprises (by mol) sodium carbonate and potassium carbonate, (45-70) and (55-30);
5. respectively connecting the composite cathode, the foamed nickel cathode and the anode with each lifting rod, suspending the composite cathode, the foamed nickel cathode and the anode above the mixed salt, and connecting each lifting rod with a top cover of the reactor in a sliding and sealing manner; sealing the reactor, vacuumizing, introducing argon and keeping the argon in the reactor;
6. heating the reactor until the mixed salt is melted to form molten salt, and then continuously heating the reactor until the reaction temperature is 750 +/-5 ℃;
7. adjusting the lifting rod to insert the foamed nickel cathode and the foamed nickel anode into the molten salt; at the moment, the foamed nickel cathode and the foamed nickel anode are respectively connected with two ends of a power supply, and 1.8-2.8V voltage is applied through the power supply to perform constant-voltage pre-electrolysis for 1-3 h; then the foamed nickel cathode is extracted from the molten salt through a lifting rod;
8. inserting the composite cathode into the molten salt through a lifting rod, connecting the composite cathode with a cathode of a power supply, and applying voltage through the power supply to perform constant-voltage electrolysis; wherein the voltage is 1.8-2.8V, and the time is 1-12 h; and taking out the composite cathode after the constant voltage electrolysis is finished, cooling to normal temperature, removing molten salt on the surface, drying to remove moisture, and preparing the lithium battery cathode material.
In the step 4, sodium carbonate and potassium carbonate are mixed according to a molar ratio of 59: 41.
In the step 1, when the pulverized coal and the manganese dioxide are ground and then subjected to ball milling and mixing, the mass ratio of the pulverized coal to the manganese dioxide in the composite material is 1-10; the grain diameter of the composite material is less than or equal to 0.1 mm.
In the step 1, when the coal powder is ground and then ball-milled to prepare fine coal powder, and then the fine coal powder and ammonia water are added into a manganese salt solution, the manganese salt solution is a manganese dichloride solution, the mass concentration of the manganese dichloride solution is 1-1.5 mol/L, the mass concentration of the ammonia water is 20-25%, the mass ratio of the coal powder to the manganese dichloride in the manganese dichloride solution is 1-10, and the mass ratio of the ammonia water to the manganese dichloride solution is 1-1.5; the grain diameter of the fine coal powder is less than or equal to 0.1 mm.
In the step 5, when the argon gas is kept flowing through the reactor, the pressure of the argon gas in the reactor is normal pressure.
In the step 6, the moisture and volatile impurities generated in the heating process are carried away by the argon gas.
In step 1, the pore size of the filter membrane used is 0.45 μm when the solid phase is filtered out.
In the step 1, the drying is carried out in a vacuum drying oven at 80 +/-2 ℃ for at least 12 h.
In the step 2, the pressure during tabletting is 3-4 MPa, and the pressure maintaining time is 90-120 s.
In the step 3, the nickel-based alloy is nickel-copper-iron alloy, which contains 11% of iron, 10% of copper and the balance of nickel by mass.
In the step 3, the mass purity of the foamed nickel is more than or equal to 99.9 percent.
In the step 8, the molten salt for removing the surface is to clean the surface by using 1mol/L hydrochloric acid, then put into water and apply ultrasonic treatment.
The lithium battery prepared by the lithium battery cathode material has the coulomb ratio of 97-102 percent, and the capacity of 450mA.h/g after the charge-discharge cycle is 200 circles.
The principle of the invention is that the pulverized coal and the manganese oxide are fully mixed and then tabletted, the performance of the pulverized coal is changed in high-temperature molten salt by an electrochemical method, impurities are removed, the structural characteristics of carbon are changed, the battery cathode material with excellent performance can be prepared, and the capacity after charging and discharging circulation of 200 circles is much higher than the common 350mA.h/g; the method has the advantages of wide raw material source, environmental friendliness, low cost, simple operation and the like; the electrochemical method is used for reducing the coal powder and the metal oxide, and the battery cathode material with excellent performance is prepared by electrolysis in the molten salt, which is beneficial to improving the surface structure of carbon, so that the composite material is more effective and economical in the aspect of battery conductive energy storage.
Detailed Description
The present invention will be described in further detail with reference to examples.
According to the embodiment of the invention, the adopted coal powder is analyzed by Eds, and contains O10-20% by mass, the balance of C and inevitable impurities, and the mass percent of the impurities is less than or equal to 1%.
The coal powder adopted in the embodiment of the invention is the coal with high quality purchased in Shanxi province.
In the embodiment of the invention, the mortar adopted for grinding is a ceramic mortar or an agate mortar.
The crucible adopted in the embodiment of the invention is a corundum crucible.
In the embodiment of the invention, after the coal powder and the manganese dioxide are ball-milled, a 150-mesh sieve (with the aperture of 0.1mm) is adopted for sieving.
When the composite cathode, the foamed nickel cathode and the anode are prepared in the embodiment of the invention, the diameter of the adopted iron wire is 0.3 +/-0.01 mm, and the material purity is 99.99%.
When the composite cathode, the foamed nickel cathode and the anode are prepared in the embodiment of the invention, the adopted stainless steel wire current collector is made of 304 stainless steel, and the diameter is 2.0 +/-0.1 mm.
The reactor in the embodiment of the invention is provided with the gas inlet and the gas outlet, and argon flows in from the gas inlet and flows out from the gas outlet.
The lifting rods in the embodiment of the invention are made of glass, the bottom of each lifting rod is fixedly connected with one stainless steel wire, and the bottom of each stainless steel wire is fixedly connected with the composite cathode, the foamed nickel cathode and the anode respectively; the lifting rod is inserted into the through hole on the top cover of the reactor and is connected with the lifting rod in a sliding and sealing way through the sealing washer on the lifting rod.
The upper part of the lifting rod in the embodiment of the invention is provided with a threaded hole and is fixed outside the reactor through a bolt; when the composite cathode, the foamed nickel cathode and the anode are positioned above the molten salt, the composite cathode, the foamed nickel cathode and the anode are inserted into the threaded hole through the bolt, and the lifting rod is fixed at a first position; when the composite cathode, the foamed nickel cathode or the anode are inserted into the molten salt, the corresponding bolts are removed, and then the lifting rod is lowered; after the composite cathode, the foamed nickel cathode or the anode are inserted into the molten salt, the composite cathode, the foamed nickel cathode or the anode is inserted into the threaded hole through the bolt, and the lifting rod is fixed at the second position.
In the embodiment of the invention, sodium carbonate and potassium carbonate are used as analytical reagents.
The nickel-copper-iron alloy adopted in the embodiment of the invention contains 11% of iron, 10% of copper and the balance of nickel by mass percent.
The purity of the foamed nickel adopted in the embodiment of the invention is 99.9%.
The manganese dioxide used in the examples of the present invention was an analytical reagent.
The ammonia water adopted in the embodiment of the invention is an analytical pure reagent.
The power supply adopted in the embodiment of the invention is a WYJ40A15V direct-current stabilized power supply.
In the embodiment of the invention, the gas outlet of the reactor extends to the position below the liquid level in the water tank outside the reactor through the pipeline, and bubbles emerge when argon gas continuously circulates.
In the embodiment of the invention, the reactor is heated by placing the reactor in a resistance wire furnace.
In the embodiment of the invention, the molten salt for removing the surface is obtained by cleaning the surface with 1mol/L hydrochloric acid, then placing the surface in water and applying ultrasonic treatment.
Example 1
Grinding and ball-milling coal powder and manganese dioxide to prepare a composite material, wherein the mass ratio of the coal powder to the manganese dioxide in the composite material is 5; the grain diameter of the composite material is less than or equal to 0.1 mm;
tabletting the composite material by a tablet machine to prepare a composite tablet material; the pressure during tabletting is 3MPa, and the pressure maintaining time is 120 s;
binding the composite pressing sheet material on a stainless steel wire current collector by using an iron wire to prepare a composite cathode; binding the foamed nickel on a stainless steel wire current collector by using an iron wire to prepare a foamed nickel cathode; connecting the nickel-based alloy with a stainless steel wire current collector to prepare an anode;
uniformly mixing sodium carbonate and potassium carbonate, placing the mixture into a crucible, then placing the crucible into a reactor, and heating the mixture to 300 +/-5 ℃ under the condition that the vacuum degree is less than or equal to 10Pa, and drying the mixture for at least 12 hours to obtain mixed salt; adding sodium carbonate and potassium carbonate in the mixed salt according to a molar ratio of 59: 41;
respectively connecting the composite cathode, the foamed nickel cathode and the anode with each lifting rod, suspending the composite cathode, the foamed nickel cathode and the anode above the mixed salt, and connecting each lifting rod with a top cover of the reactor in a sliding and sealing manner; sealing the reactor, vacuumizing, introducing argon and keeping the argon in the reactor; the pressure of argon in the reactor is normal pressure;
heating the reactor until the mixed salt is melted to form molten salt, and then continuously heating the reactor until the reaction temperature is 750 +/-5 ℃; moisture and volatile impurities generated in the heating process are taken away by argon;
adjusting the lifting rod to insert the foamed nickel cathode and the foamed nickel anode into the molten salt; at the moment, the cathode and the anode of the foamed nickel are respectively connected with two ends of a power supply, 1.8 voltage is applied through the power supply, and constant-voltage pre-electrolysis is carried out for 3 hours; then the foamed nickel cathode is extracted from the molten salt through a lifting rod;
inserting the composite cathode into the molten salt through a lifting rod, connecting the composite cathode with a cathode of a power supply, and applying voltage through the power supply to perform constant-voltage electrolysis; wherein the voltage is 1.8-2.8V, and the time is 1-12 h; taking out the composite cathode after constant voltage electrolysis, cooling to normal temperature, removing molten salt on the surface, drying to remove water, and preparing the lithium battery cathode material;
after the lithium battery prepared by using the negative electrode material of the lithium battery as a cathode and the nickel-based alloy as an anode is subjected to charge-discharge cycle for 200 circles, the capacity of the lithium battery is 450 mA.h/g.
Example 2
The method is the same as example 1, except that:
(1) grinding and ball-milling the coal powder to prepare fine coal powder, adding the fine coal powder and ammonia water into a manganese salt solution, uniformly stirring and mixing, filtering to obtain a solid phase, and drying to remove water to prepare a composite material; the manganese salt solution is a manganese dichloride solution, the mass concentration of the manganese dichloride solution is 1mol/L, the mass concentration of ammonia water is 20%, the mass ratio of the coal powder to the manganese dichloride in the manganese dichloride solution is 5, and the mass ratio of the ammonia water to the manganese dichloride solution is 1; the particle size of the fine coal powder is less than or equal to 0.1 mm; the aperture of the adopted filter membrane is 0.45 micron; the drying is carried out in a vacuum drying oven at 80 +/-2 ℃ for at least 12 h;
(2) the pressure during tabletting is 4MPa, and the pressure maintaining time is 90 s;
(3) the mixed salt is prepared by mixing sodium carbonate and potassium carbonate in a molar ratio of 48: 52;
(4) the voltage of constant-voltage pre-electrolysis is 2.8V, and the time is 1 h;
(5) the lithium battery cathode material is used as a cathode, and the capacity of the prepared lithium battery is 430mA.h/g after the charge-discharge cycle of 200 circles.
Example 3
The method is the same as example 1, except that:
(1) the mass ratio of the coal powder to the manganese dioxide in the composite material is 1;
(2) the pressure during tabletting is 3.5MPa, and the pressure maintaining time is 100 s;
(3) adding sodium carbonate and potassium carbonate in the mixed salt according to a molar ratio of 45: 55;
(4) the voltage of constant-voltage pre-electrolysis is 2.3V, and the time is 2 h;
(5) after the lithium battery prepared by adopting the negative electrode material of the lithium battery as the cathode is subjected to charge-discharge cycle for 200 circles, the capacity is 4440 mA.h/g.
Example 4
The method is the same as example 1, except that:
(1) grinding and ball-milling the coal powder to prepare fine coal powder, adding the fine coal powder and ammonia water into a manganese salt solution, uniformly stirring and mixing, filtering to obtain a solid phase, and drying to remove water to prepare a composite material; the manganese salt solution is a manganese dichloride solution, the mass concentration of the manganese dichloride solution is 1.5mol/L, the mass concentration of ammonia water is 25%, the mass ratio of the coal powder to the manganese dichloride in the manganese dichloride solution is 10, and the mass ratio of the ammonia water to the manganese dichloride solution is 1.5; the particle size of the fine coal powder is less than or equal to 0.1 mm; the aperture of the adopted filter membrane is 0.45 micron; the drying is carried out in a vacuum drying oven at 80 +/-2 ℃ for at least 12 h;
(2) the pressure during tabletting is 3.5MPa, and the pressure maintaining time is 100 s;
(3) adding sodium carbonate and potassium carbonate into the mixed salt according to a molar ratio of 70: 30;
(4) the voltage of constant voltage pre-electrolysis is 2.5V, and the time is 1.5 h;
(5) after the lithium battery prepared by adopting the negative electrode material of the lithium battery as a cathode is subjected to charge-discharge cycle for 200 circles, the capacity is 421 mA.h/g.
Example 5
The method is the same as example 1, except that:
(1) the mass ratio of the coal powder to the manganese dioxide in the composite material is 10;
(2) the pressure during tabletting is 3.5MPa, and the pressure maintaining time is 100 s;
(3) the mixed salt is prepared by mixing sodium carbonate and potassium carbonate according to a molar ratio of 66: 34;
(4) the voltage of constant-voltage pre-electrolysis is 2.1V, and the time is 2.5 h;
(5) after the prepared lithium battery negative electrode material is used as a cathode, the capacity is 435mA.h/g after the prepared lithium battery is subjected to charge-discharge cycle for 200 circles.
Example 6
The method is the same as example 1, except that:
(1) grinding and ball-milling the coal powder to prepare fine coal powder, adding the fine coal powder and ammonia water into a manganese salt solution, uniformly stirring and mixing, filtering to obtain a solid phase, and drying to remove water to prepare a composite material; the manganese salt solution is a manganese dichloride solution, the mass concentration of the manganese dichloride solution is 1.2mol/L, the mass concentration of ammonia water is 23%, the mass ratio of the coal powder to the manganese dichloride in the manganese dichloride solution is 1, and the mass ratio of the ammonia water to the manganese dichloride solution is 1.3; the particle size of the fine coal powder is less than or equal to 0.1 mm; the aperture of the adopted filter membrane is 0.45 micron; the drying is carried out in a vacuum drying oven at 80 +/-2 ℃ for at least 12 h;
(2) the pressure during tabletting is 4MPa, and the pressure maintaining time is 90 s;
(3) adding sodium carbonate and potassium carbonate into the mixed salt according to a molar ratio of 50: 50;
(4) the voltage of constant-voltage pre-electrolysis is 2.3V, and the time is 2 h;
(5) after the lithium battery prepared by adopting the negative electrode material of the lithium battery as the cathode is subjected to charge-discharge cycle for 200 circles, the capacity is 447 mA.h/g.
Example 7
The method is the same as example 1, except that:
(1) the mass ratio of the coal powder to the manganese dioxide in the composite material is 3;
(2) the pressure during tabletting is 4MPa, and the pressure maintaining time is 90 s;
(3) adding sodium carbonate and potassium carbonate in the mixed salt according to a molar ratio of 55: 45;
(4) the voltage of constant voltage pre-electrolysis is 2.5V, and the time is 1.5 h;
(5) the capacity of the prepared lithium battery is 441mA.h/g after the lithium battery is subjected to charge-discharge cycle for 200 circles by using the lithium battery cathode material as a cathode.
Example 8
The method is the same as example 1, except that:
(1) grinding and ball-milling the coal powder to prepare fine coal powder, adding the fine coal powder and ammonia water into a manganese salt solution, uniformly stirring and mixing, filtering to obtain a solid phase, and drying to remove water to prepare a composite material; the manganese salt solution is a manganese dichloride solution, the mass concentration of the manganese dichloride solution is 1.3mol/L, the mass concentration of ammonia water is 24%, the mass ratio of the coal powder to the manganese dichloride in the manganese dichloride solution is 9, and the mass ratio of the ammonia water to the manganese dichloride solution is 1.2; the particle size of the fine coal powder is less than or equal to 0.1 mm; the aperture of the adopted filter membrane is 0.45 micron; the drying is carried out in a vacuum drying oven at 80 +/-2 ℃ for at least 12 h;
(2) the pressure during tabletting is 4MPa, and the pressure maintaining time is 90 s;
(3) mixing the mixed salt with sodium carbonate and potassium carbonate in a molar ratio of 60: 40;
(4) the voltage of constant-voltage pre-electrolysis is 2.1V, and the time is 2.5 h;
(5) after the prepared lithium battery negative electrode material is used as a cathode, the capacity of the prepared lithium battery is 428mA.h/g after the charge-discharge cycle is 200 circles.
Example 9
The method is the same as example 1, except that:
(1) the mass ratio of the coal powder to the manganese dioxide in the composite material is 8;
(2) the pressure during tabletting is 4MPa, and the pressure maintaining time is 90 s;
(3) adding sodium carbonate and potassium carbonate in the mixed salt according to a molar ratio of 65: 35;
(4) the voltage of constant-voltage pre-electrolysis is 2V, and the time is 3 h;
(5) after the lithium battery prepared by adopting the negative electrode material of the lithium battery as a cathode is subjected to charge-discharge cycle for 200 circles, the capacity is 432 mA.h/g.
Example 10
The method is the same as example 1, except that:
(1) grinding and ball-milling the coal powder to prepare fine coal powder, adding the fine coal powder and ammonia water into a manganese salt solution, uniformly stirring and mixing, filtering to obtain a solid phase, and drying to remove water to prepare a composite material; the manganese salt solution is a manganese dichloride solution, the mass concentration of the manganese dichloride solution is 1.1mol/L, the mass concentration of ammonia water is 21%, the mass ratio of the coal powder to the manganese dichloride in the manganese dichloride solution is 8, and the mass ratio of the ammonia water to the manganese dichloride solution is 1.4; the particle size of the fine coal powder is less than or equal to 0.1 mm; the aperture of the adopted filter membrane is 0.45 micron; the drying is carried out in a vacuum drying oven at 80 +/-2 ℃ for at least 12 h;
(2) the pressure during tabletting is 4MPa, and the pressure maintaining time is 90 s;
(3) adding sodium carbonate and potassium carbonate in the mixed salt according to a molar ratio of 53: 47;
(4) the voltage of constant-voltage pre-electrolysis is 2.6V, and the time is 1.2 h;
(5) after the prepared lithium battery negative electrode material is used as a cathode, the capacity is 429mA.h/g after the prepared lithium battery is subjected to charge-discharge cycle for 200 circles.
Claims (8)
1. A method for preparing a lithium battery cathode material by high-temperature molten salt constant-voltage electrolysis is characterized by comprising the following steps:
(1) grinding and ball-milling and mixing the coal powder and manganese dioxide to prepare a composite material; or grinding the coal powder and then ball-milling to prepare fine coal powder, adding the fine coal powder and ammonia water into a manganese salt solution, stirring and mixing uniformly, filtering to obtain a solid phase, and drying to remove water to prepare the composite material;
(2) tabletting the composite material by a tablet machine to prepare a composite tablet material;
(3) binding the composite pressing sheet material on a stainless steel wire current collector by using an iron wire to prepare a composite cathode; binding the foamed nickel on a stainless steel wire current collector by using an iron wire to prepare a foamed nickel cathode; connecting the nickel-based alloy with a stainless steel wire current collector to prepare an anode;
(4) uniformly mixing sodium carbonate and potassium carbonate, placing the mixture into a crucible, then placing the crucible into a reactor, and heating the mixture to 300 +/-5 ℃ under the condition that the vacuum degree is less than or equal to 10Pa, and drying the mixture for at least 12 hours to obtain mixed salt; the mixed salt comprises (by mol) sodium carbonate and potassium carbonate, (45-70) and (55-30);
(5) respectively connecting the composite cathode, the foamed nickel cathode and the anode with each lifting rod, suspending the composite cathode, the foamed nickel cathode and the anode above the mixed salt, and connecting each lifting rod with a top cover of the reactor in a sliding and sealing manner; sealing the reactor, vacuumizing, introducing argon and keeping the argon in the reactor;
(6) heating the reactor until the mixed salt is melted to form molten salt, and then continuously heating the reactor until the reaction temperature is 750 +/-5 ℃;
(7) adjusting the lifting rod to insert the foamed nickel cathode and the foamed nickel anode into the molten salt; at the moment, the foamed nickel cathode and the foamed nickel anode are respectively connected with two ends of a power supply, and 1.8-2.8V voltage is applied through the power supply to perform constant-voltage pre-electrolysis for 1-3 h; then the foamed nickel cathode is extracted from the molten salt through a lifting rod;
(8) inserting the composite cathode into the molten salt through a lifting rod, connecting the composite cathode with a cathode of a power supply, and applying voltage through the power supply to perform constant-voltage electrolysis; wherein the voltage is 1.8-2.8V, and the time is 1-12 h; and taking out the composite cathode after the constant voltage electrolysis is finished, cooling to normal temperature, removing molten salt on the surface, drying to remove moisture, and preparing the lithium battery cathode material.
2. The method for preparing the lithium battery cathode material through high-temperature molten salt constant-voltage electrolysis according to claim 1, wherein in the step (1), when pulverized coal and manganese dioxide are ground and then subjected to ball milling and mixing, the mass ratio of the pulverized coal to the manganese dioxide in the composite material is 1-10; the grain diameter of the composite material is less than or equal to 0.1 mm.
3. The method for preparing the lithium battery cathode material through high-temperature molten salt constant-voltage electrolysis according to claim 1, wherein in the step (1), when pulverized coal is ground and then ball-milled to prepare fine coal powder, and then the fine coal powder and ammonia water are added into a manganese salt solution, the manganese salt solution is a manganese dichloride solution, the mass concentration of the manganese dichloride solution is 1-1.5 mol/L, the mass concentration of the ammonia water is 20-25%, the mass ratio of the pulverized coal to the manganese dichloride in the manganese dichloride solution is 1-10, and the mass ratio of the ammonia water to the manganese dichloride solution is 1-1.5; the grain diameter of the fine coal powder is less than or equal to 0.1 mm.
4. The method for preparing the negative electrode material of the lithium battery through the constant-voltage electrolysis of the high-temperature molten salt according to claim 1, wherein in the step (1), the aperture of the filter membrane used when the solid phase is filtered out is 0.45 microns.
5. The method for preparing the negative electrode material of the lithium battery through the high-temperature molten salt constant-voltage electrolysis according to claim 1, wherein in the step (4), the molar ratio of sodium carbonate to potassium carbonate in the mixed salt is 59: 41.
6. The method for preparing the negative electrode material of the lithium battery through the high-temperature molten salt constant-voltage electrolysis according to claim 1, wherein in the step (2), the pressure during tabletting is 3-4 MPa, and the pressure maintaining time is 90-120 s.
7. The method for preparing the negative electrode material of the lithium battery through the constant-voltage electrolysis of the high-temperature molten salt according to claim 1, wherein in the step (3), the nickel-based alloy is a nickel-copper-iron alloy, and comprises 11% of iron, 10% of copper and the balance of nickel by mass percent.
8. The method for preparing the lithium battery cathode material by the high-temperature molten salt constant-voltage electrolysis according to claim 1, wherein the mass purity of the foamed nickel is more than or equal to 99.9%.
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| HAI ZHANG ET.AL: "Molten-Salt-Assisted Synthesis of Hierarchical Porous MnO@Biocarbon Composites as Promising Electrode Materials for Supercapacitors and Lithium-Ion Batteries", 《CHEMSUSCHEM》 * |
| 封萍 等: "无烟煤基CO2吸附材料及电极材料的制备", 《矿业科学学报》 * |
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