CN113903882A - Solid-state lithium-sulfur battery, battery positive electrode and preparation method thereof - Google Patents

Solid-state lithium-sulfur battery, battery positive electrode and preparation method thereof Download PDF

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CN113903882A
CN113903882A CN202111159108.1A CN202111159108A CN113903882A CN 113903882 A CN113903882 A CN 113903882A CN 202111159108 A CN202111159108 A CN 202111159108A CN 113903882 A CN113903882 A CN 113903882A
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刘张波
赵嫣然
王鑫萌
朱晗
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China Automotive Innovation Co Ltd
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Abstract

The invention discloses a solid-state lithium-sulfur battery anode which mainly comprises the following components in percentage by mass: 5-30% of solid electrolyte, 60-85% of elemental sulfur, 5-30% of carbon carrier and 0.1-10% of binder, wherein the solid electrolyte is binary sulfide (Li)2S)a(P2S5)1‑aOr ternary sulfides (Li)2S)b(P2S5)c(LiX)1‑b‑c. The solid electrolyte is prepared by synthesizing sulfur, lithium triethylborohydride, phosphorus pentasulfide and optional other components step by step in the presence of a carbon carrier, each reaction step is carried out on the surface and in a pore channel of the carbon carrier, the synthesized solid electrolyte is uniformly distributed on the carbon carrier, molecular-level mixing is realized between elemental sulfur and the carbon carrier, and the contact performance between active components of the anode is improved.

Description

Solid-state lithium-sulfur battery, battery positive electrode and preparation method thereof
Technical Field
The invention belongs to the technical field of solid-state batteries, and relates to a solid-state lithium-sulfur battery, a battery anode and a preparation method thereof.
Background
Lithium ion batteries have become the mainstream mobile portable power source in the modern society, and are widely applied to notebook computers, mobile phones and other portable electrical appliances. The technical progress promotes the application range of the lithium ion battery to be wider and wider, and the lithium battery is gradually expanded from the fields of mobile phones, notebook computers to electric bicycles, electric automobiles and the like. With the rise of the electric automobile industry, people have further demands on the endurance, service life and safety performance of power batteries for electric automobiles, and the development of safe high-energy-density lithium batteries becomes the key point of the next-stage research and development.
In a new energy storage system, the theoretical energy density of a lithium-sulfur battery (Li/S battery) taking metal lithium as a negative electrode and elemental sulfur as a positive electrode can reach 2600Whkg-1The specific capacity of the sulfur anode is 1675mAhg-1Is far larger than 300Whkg of the commercial lithium ion battery using graphite as the negative electrode-1. Therefore, the lithium-sulfur battery taking the metal lithium as the negative electrode has great application prospect in the development of future chemical power sources. The solid-state lithium-sulfur battery does not contain liquid electrolyte, so that metal lithium pulverization caused by the reaction of the electrolyte and the metal lithium in the charge-discharge cycle of the conventional liquid-state lithium-sulfur battery is avoided, and further the safety problems of battery failure, even fire explosion and the like are avoided. In the conventional preparation method of the solid-state lithium-sulfur battery anode, the solid electrolyte and materials such as elemental sulfur, carbon materials, binders and the like are mechanically mixed, the solid electrolyte and other components in the anode are not uniformly dispersed among particles, the contact is poor, the ionic conductivity of the anode is low, and the exerted capacity of the solid-state lithium-sulfur battery anode and the cycle performance of the battery are further influenced.
To solve this problem, for example, chinese patent application publication No. CN113036073A, published No. 2021.06.25, filed as china academy of sciences shanghai silicate research institute and corning incorporated, discloses a composite positive electrode for solid-state lithium-sulfur battery and a method for preparing the same, the composite positive electrode being composed of active element sulfur, conductive carbon and a sulfide electrolyte, and the sulfide electrolyte being uniformly coated on at least one surface of the conductive carbon. The preparation method comprises the steps of carbonizing cotton fibers at high temperature to obtain carbon fiber (CDCF) powder, coating an electrolyte on the CDCF in situ to form composite powder, and grinding and co-heating the composite powder and active sulfur powder to obtain the composite anode powder. The invention improves the interface contact between the carbon fiber and the sulfide lithium ion conductor by coating the conductive carbon component with the sulfide electrolyte by a liquid phase method. The invention improves the ionic conductivity of the positive electrode, but does not show whether the cycle performance of the battery can be improved.
Disclosure of Invention
In order to solve the problems of uneven dispersion, poor contact and low anode ionic conductivity between solid electrolyte and other components of the anode in the solid-state lithium-sulfur battery, the invention provides the solid-state lithium-sulfur battery anode and the preparation method thereof.
The solid-state lithium-sulfur battery positive electrode mainly comprises a solid electrolyte, elemental sulfur, a carbon carrier and a binder. The solid electrolyte is prepared by synthesizing sulfur, lithium triethylborohydride, phosphorus pentasulfide and optional other components step by step under the condition of premixing with a carbon material.
The solid-state lithium-sulfur battery positive electrode is characterized by mainly comprising the following components in percentage by mass:
Figure BDA0003289438340000021
wherein the solid electrolyte is a binary sulfide (Li)2S)a(P2S5)1-aOr ternary sulfides (Li)2S)b(P2S5)c(LiX)1-b-cX is selected from one or more of Cl, Br and I, a is more than 0 and less than 1, b is more than 0 and less than 1, c is more than 0 and less than 1, and b + c is more than 0 and less than 1.
The preparation method of the solid-state lithium-sulfur battery positive electrode comprises the following steps:
(1) dissolving sulfur in a solvent, adding a carbon carrier, and uniformly mixing to obtain a suspension; then adding a tetrahydrofuran solution of lithium triethylborohydride, mixing the tetrahydrofuran solution with the suspension, and drying and removing the solvent to obtain a first mixture of lithium sulfide and a carbon carrier; carrying out the step (2) or directly carrying out the step (3);
(2) dissolving LiX (X ═ Cl, Br, I) in a solvent, mixing with a first mixture of lithium sulfide and carbon support, and then drying off the solvent to obtain a second mixture of lithium sulfide, LiX and carbon support;
(3) heating the first mixture or the second mixture obtained in the step (1) or the step (2) and phosphorus pentasulfide to over 276 ℃ under a vacuum condition (preferably 280 ℃), mixing, and cooling to obtain a third mixture;
(4) roasting the third mixture obtained in the step (3) to obtain a fourth mixture of the solid electrolyte and the carbon carrier;
(5) adding a solution dissolved with elemental sulfur into the fourth mixture of the solid electrolyte and the carbon carrier, mixing, and drying to remove the solvent to obtain a fifth mixture;
(6) and mixing the fifth mixture with a binder, and then carrying out extrusion forming to obtain the solid-state lithium-sulfur battery anode.
The method is characterized in that in the process of synthesizing the anode of the solid-state lithium-sulfur battery, under the condition of the existence of a carbon carrier, the initial raw materials of sulfur and lithium triethylborohydride are synthesized step by step, each reaction step is carried out on the surface and in a pore channel of the carbon carrier, materials are added and mixed in a solution (lithium source and sulfur) or melting (phosphorus pentasulfide) mode, particles as small as possible are attached to the surface of the carbon carrier and enter the pore channel of the carbon carrier, the dispersion is more uniform, the synthesis of the solid electrolyte by high-temperature roasting at the expected stoichiometric ratio is facilitated, the solid electrolyte is uniformly distributed on the carbon carrier, the elemental sulfur and the carbon carrier containing the solid electrolyte are mixed at a molecular level, and the contact performance between active components of the anode is improved.
Wherein the solid electrolyte is preferably Li3PS4、Li6PS5X(X＝Cl、Br、I)、Li7P3S11One kind of (1).
Wherein, the solvent for dissolving the elemental sulfur is one of carbon tetrachloride, benzene, acetone, trichloromethane, trichloroethylene and carbon disulfide. Preferably, the solvent is carbon disulfide.
Wherein the solvent of the LiX solution is one of ethanol, acetone, diethyl ether and pyridine, and ethanol is preferred.
The carbon carrier is one of carbon fiber, carbon nano tube, graphene carbon nano tube hybrid and activated carbon.
Preferably, the specific surface area of the carbon carrier is 10-1000 m2The pore diameter of the carbon carrier is 0.5-100 nm.
And (3) grinding the third mixture in the step (4) before roasting, wherein the grinding is preferably performed by ball milling for 1-3 hours under a vacuum condition.
The roasting is preferably carried out for 30 minutes to 1 hour at the temperature of 500 ℃ to 600 ℃ under the protection of argon atmosphere.
Wherein the binder is one of polyvinylpyrrolidone (PVP), Polytetrafluoroethylene (PTFE), polymethyl methacrylate (PMMA) and polyethylene glycol (PEO).
The single-side sulfur surface loading capacity of the solid-state lithium-sulfur battery anode is 0.5-8 mg/cm2。
The invention also relates to a solid-state lithium-sulfur battery, which comprises the solid-state lithium-sulfur battery positive electrode.
Has the advantages that: according to the solid-state lithium-sulfur battery anode, the solid electrolyte is directly synthesized on the surface of the carbon carrier and in the pore canal, and the elemental sulfur and the carbon carrier containing the solid electrolyte are mixed in a molecular level, so that the contact performance among all components of the anode is greatly improved, the ionic conductivity of the solid-state battery lithium-sulfur anode is further improved, the exerted capacity of the battery is improved, and the service life of the battery is prolonged.
Drawings
FIG. 1 comparison of specific discharge capacities of the positive electrodes of the solid-state lithium-sulfur batteries of example 1 and comparative example 1;
fig. 2 is a comparison of specific discharge capacities of the solid-state lithium-sulfur battery positive electrodes of example 2 and comparative example 2.
Detailed Description
The present invention will be described in detail with reference to specific examples. It is intended that the scope of the invention be limited not by this detailed description, but rather by the claims appended hereto.
Example 1
The solid-state lithium-sulfur battery positive electrode comprises a solid electrolyte Li in percentage by mass3PS4Elemental sulfur S, carbon nanotube CNT and binder PEO 25:60:5: 10. The preparation method comprises weighing solid electrolyte Li according to stoichiometric ratio3PS4Preparing the required raw materials, and weighing the elemental sulfur S, the carbon nano tube CNT and the bonding agent PEO according to the component proportion, wherein the method comprises the following steps:
(1) adding carbon nano tubes into a carbon disulfide solution (20 wt%) containing sulfur weighed according to a stoichiometric ratio, and fully mixing to obtain a suspension;
(2) mixing and stirring 1mol/L tetrahydrofuran solution of lithium triethylborohydride and the carbon disulfide suspension containing the carbon nano tube and sulfur for 1 hour, and completely drying and removing the tetrahydrofuran and the carbon disulfide to obtain a mixture of lithium sulfide and the carbon nano tube;
(3) mixing the mixture of the lithium sulfide and the carbon nano tube with phosphorus pentasulfide, heating the mixture for 1 hour in vacuum at the temperature of 280 ℃, and naturally cooling the mixture to room temperature;
(4) ball-milling the material in a vacuum grinding tank for 3 hours, taking out, roasting for 1 hour under the protection of argon atmosphere at 600 ℃, and naturally cooling to obtain Li3PS4And carbon nanotubes;
(5) in solid electrolyte Li3PS4Adding a carbon disulfide solution (20 wt%) of elemental sulfur into the mixture of the carbon nanotubes, fully mixing, drying, completely volatilizing the carbon disulfide solution, and keeping the elemental sulfur in the material;
(6) mixing the materials with a PEO binder, and then carrying out extrusion molding to obtain a solid-state lithium-sulfur battery anode with the required thickness; the single-side sulfur surface loading capacity of the positive electrode is 1mg/cm2。
The solid-state lithium-sulfur battery positive electrode and the solid electrolyte Li are prepared by3PS4And assembling the lithium battery by the metal lithium according to a conventional lamination process. By adopting the LAND test system, the assembled battery is tested for the cycle retention rate of 69.4% at 100 circles under the conditions that the current is 0.05C and the charging and discharging voltage range is 1.5-2.5V, which is shown in figure 1.
Example 2
The solid-state lithium-sulfur battery positive electrode comprises a solid electrolyte Li in percentage by mass6PS5Cl elemental sulfur S, carbon nanotube CNT, binder PMMA 5:60:30: 5. The preparation method comprises weighing solid electrolyte Li according to stoichiometric ratio6PS5Cl prepares the required raw materials, and the elemental sulfur S, the carbon nano tube CNT and the adhesive PMMA are weighed according to the component proportion, and the method comprises the following steps:
(1) adding carbon nano tubes into a carbon disulfide solution (20 wt%) containing sulfur weighed according to a stoichiometric ratio, and fully mixing to obtain a suspension;
(2) mixing and stirring 1mol/L tetrahydrofuran solution of lithium triethylborohydride and the carbon disulfide suspension containing the carbon nano tube and sulfur for 1 hour, and completely drying and removing the tetrahydrofuran and the carbon disulfide to obtain a mixture of lithium sulfide and the carbon nano tube;
(3) dissolving lithium chloride in alcohol, and fully mixing the lithium chloride with the mixture of the lithium sulfide and the carbon nano tube to fully volatilize the alcohol;
(4) mixing the mixture of the lithium sulfide, the lithium chloride and the carbon nano tube with phosphorus pentasulfide, heating the mixture for 1 hour in vacuum at 280 ℃, and naturally cooling the mixture to room temperature;
(5) ball-milling the material in a vacuum grinding tank for 3 hours, taking out, roasting for 0.5 hour under the protection of argon atmosphere at 500 ℃, and naturally cooling to obtain Li6PS5A mixture of Cl and carbon nanotubes;
(6) in solid electrolyte Li6PS5Adding a carbon disulfide solution (20 wt%) of elemental sulfur into the mixture of Cl and the carbon nano tube, fully mixing, drying, completely volatilizing the carbon disulfide solution, and keeping the elemental sulfur in the material;
(7) mixing the materials with a PMMA (polymethyl methacrylate) binder, and then carrying out extrusion forming to obtain a solid lithium-sulfur battery anode with the required thickness; the single-side sulfur surface loading capacity of the positive electrode is 1mg/cm2。
The solid-state lithium-sulfur battery positive electrode and the solid electrolyte Li are prepared by6PS5And assembling the lithium battery by Cl and metal lithium according to a conventional lamination process. By adopting the LAND test system, the assembled battery is tested for the cycle retention rate of 72.5% for 100 circles under the conditions that the current is 0.05C and the charging and discharging voltage range is 1.5-2.5V, which is shown in figure 2.
Example 3
The solid-state lithium-sulfur battery positive electrode comprises a solid electrolyte Li in percentage by mass6PS5Cl, elemental sulfur S, graphene carbon nanotube hybrid and binder PTFE of 9.9:85:5: 0.1. The preparation method comprises weighing solid electrolyte Li according to stoichiometric ratio6PS5Cl prepares the required raw materials, and the elemental sulfur S, the graphene carbon nanotube hybrid and the binder PTFE are weighed according to the proportion of the components, and the method comprises the following steps:
(1) adding the graphene carbon nanotube hybrid into a carbon disulfide solution (20 wt%) containing sulfur in a stoichiometric ratio, and fully mixing to obtain a suspension;
(2) mixing and stirring 1mol/L tetrahydrofuran solution of lithium triethylborohydride and the carbon disulfide turbid liquid containing the graphene carbon nanotube hybrid and sulfur for 1 hour, and completely drying and removing tetrahydrofuran and carbon disulfide to obtain a mixture of lithium sulfide and the graphene carbon nanotube hybrid;
(3) dissolving lithium chloride in alcohol, fully mixing with the mixture of the lithium sulfide and the graphene carbon nanotube hybrid, and fully volatilizing the alcohol;
(4) mixing the mixture of the lithium sulfide, the lithium chloride and the graphene carbon nanotube hybrid with phosphorus pentasulfide, heating the mixture for 1 hour in vacuum at 280 ℃, and naturally cooling the mixture to room temperature;
(5) ball-milling the material in a vacuum grinding tank for 3 hours, taking out, roasting for 0.5 hour under the protection of argon atmosphere at 500 ℃, and naturally cooling to obtain Li6PS5A mixture of Cl and graphene carbon nanotube hybrids;
(6) in solid electrolyte Li6PS5Adding a carbon disulfide solution (20 wt%) of elemental sulfur into the mixture of the Cl and the graphene carbon nanotube hybrid, fully mixing, drying, completely volatilizing the carbon disulfide solution, and keeping the elemental sulfur in the material;
(7) mixing the materials with a PTFE binder, and then carrying out extrusion molding to obtain a solid-state lithium-sulfur battery anode with the required thickness; the single-side sulfur surface loading capacity of the positive electrode is 6mg/cm2。
The solid-state lithium-sulfur battery positive electrode and the solid electrolyte Li are prepared by6PS5And assembling the lithium battery by Cl and metal lithium according to a conventional lamination process. By using the LAND test system, the assembled battery is tested to have 60.6 percent of cycle retention rate after 100 circles under the conditions that the current is 0.05C and the charging and discharging voltage range is 1.5-2.5V.
Example 4
The solid-state lithium-sulfur battery positive electrode comprises a solid electrolyte Li in percentage by mass6PS5Cl, elemental sulfur S, carbon fiber, binder PTFE, 15:75:5: 5. The preparation method comprises weighing solid electrolyte Li according to stoichiometric ratio6PS5Cl prepares the required raw materials, and the elemental sulfur S, the carbon fiber and the binder PTFE are weighed according to the proportion of the components, and the method comprises the following steps:
(1) adding carbon fibers into a carbon disulfide solution (20% by weight) containing sulfur in a stoichiometric ratio, and fully mixing to obtain a suspension;
(2) mixing and stirring a tetrahydrofuran solution (1mol/L) of lithium triethylborohydride and the carbon disulfide suspension containing carbon fibers and sulfur for 1 hour, and completely drying and removing the tetrahydrofuran and the carbon disulfide to obtain a mixture of lithium sulfide and carbon fibers;
(3) dissolving lithium chloride in alcohol, fully mixing with the mixture of the lithium sulfide and the carbon fiber, and fully volatilizing the alcohol;
(4) mixing the mixture of the lithium sulfide, the lithium chloride and the carbon fiber with a phosphorus pentasulfide material, heating the mixture for 1 hour in vacuum at 280 ℃, and naturally cooling the mixture to room temperature;
(5) ball-milling the material in a vacuum grinding tank for 3 hours, taking out, roasting for 1 hour under the protection of argon atmosphere at 600 ℃, and naturally cooling to obtain Li6PS5A mixture of Cl and carbon fibers;
(6) in solid electrolyte Li6PS5Adding a carbon disulfide solution (20 wt%) of elemental sulfur into the mixture of Cl and the carbon fibers, fully mixing, drying, completely volatilizing the carbon disulfide solution, and keeping the elemental sulfur in the material;
(7) mixing the materials with a PTFE binder, and carrying out extrusion molding to obtain a solid-state lithium-sulfur battery anode with a required thickness; the single-side sulfur surface loading capacity of the positive electrode is 4mg/cm2。
The solid-state lithium-sulfur battery positive electrode and the solid electrolyte Li are prepared by6PS5Cl and metal lithium are assembled into the lithium battery according to a conventional lamination process; by adopting the LAND test system, the assembled battery is tested to have 70.8% of cycle retention rate for 100 circles under the conditions that the current is 0.05C and the charging and discharging voltage interval is 1.5-2.5V.
Example 5
The solid-state lithium-sulfur battery positive electrode comprises a solid electrolyte Li in percentage by mass7P3S11Elemental sulfur S, graphene, binder PTFE, 30:64:5: 1. The preparation method comprises weighing solid electrolyte Li according to stoichiometric ratio7P3S11Preparing the required raw materials, and weighing the elemental sulfur S, the graphene and the binder according to the proportion of the componentsPTFE, comprising the steps of:
(1) adding graphene into a carbon disulfide solution (20% wt) containing sulfur in a stoichiometric ratio, and fully mixing to obtain a suspension;
(2) mixing and stirring a tetrahydrofuran solution (1mol/L) of lithium triethylborohydride and the carbon disulfide turbid liquid containing graphene and sulfur for 1 hour, and completely drying and removing the tetrahydrofuran and the carbon disulfide to obtain a mixture of lithium sulfide and graphene;
(3) mixing the mixture of the lithium sulfide and the graphene with phosphorus pentasulfide, heating the mixture for 1 hour in vacuum at 280 ℃, and naturally cooling the mixture to room temperature;
(4) ball-milling the material in a vacuum grinding tank for 3 hours, taking out, roasting for 1 hour under the protection of argon atmosphere at 600 ℃, and naturally cooling to obtain Li7P3S11And graphene;
(5) the above solid electrolyte Li7P3S11Adding a carbon disulfide solution (20 wt%) of elemental sulfur into the mixture of the graphene and the graphene, fully mixing, drying, completely volatilizing the carbon disulfide solution, and keeping the elemental sulfur in the material;
(6) mixing the materials with a PTFE binder, and carrying out extrusion molding to obtain a solid-state lithium-sulfur battery anode with a required thickness; the single-side sulfur surface loading capacity of the positive electrode is 4mg/cm2。
The solid-state lithium-sulfur battery positive electrode and the solid electrolyte Li are prepared by7P3S11And assembling the lithium battery by the metal lithium according to a conventional lamination process. By adopting the LAND test system, the assembled battery is tested to have 66.5% of cycle retention rate for 100 circles under the conditions that the current is 0.05C and the charging and discharging voltage interval is 1.5-2.5V.
Comparative example 1
(1) Preparing a positive electrode and assembling a battery: as solid electrolyte Li3PS4Weighing the materials according to the mass ratio of elemental sulfur S to carbon nanotube CNT to binder PEO of 25:60:5:10, fully mixing and extruding to obtain the self-made lithium-sulfur battery anode with the single-side sulfur surface loading of 1mg/cm2. The positive electrode and the solid electrolyte Li3PS4And assembling the lithium battery by the three according to a conventional lamination process.
(2) And (3) testing the battery performance: by adopting the LAND test system, the assembled battery is tested for the cycle performance under the conditions that the current is 0.05C and the charging and discharging voltage interval is 1.5-2.5V, and the cycle retention rate is 46.3% after 100 circles, which is shown in figure 1.
Comparative example 2
(1) Preparing a positive electrode and assembling a battery: as solid electrolyte Li6PS5Respectively weighing the materials according to the mass ratio of Cl, elemental sulfur S, carbon nano tube CNT and binder PMMA of 5:60:30:5, fully mixing and extruding and forming to obtain the self-made lithium-sulfur battery anode with the single-side sulfur surface loading of 1mg/cm2. The positive electrode and the solid electrolyte Li6PS5And assembling the lithium battery by the Cl and the metal lithium according to a conventional lamination process.
(2) And (3) testing the battery performance: by adopting the LAND test system, the assembled battery is tested for the cycle performance under the conditions that the current is 0.05C and the charging and discharging voltage range is 1.5-2.5V, the cycle retention rate is 35.3% after 100 circles, and the figure is shown in figure 2.
Comparative example 3
(1) Preparing a positive electrode and assembling a battery: as solid electrolyte Li6PS5Respectively weighing the materials according to the mass ratio of Cl, elemental sulfur S, graphene carbon nanotube hybrid and binder PTFE of 9.9:85:5:0.1, fully mixing and extruding to obtain a self-made lithium-sulfur battery anode with the single-side sulfur surface loading of 6mg/cm2. The positive electrode and the solid electrolyte Li6PS5And assembling the lithium battery by the Cl and the metal lithium according to a conventional lamination process.
(2) And (3) testing the battery performance: by adopting the LAND test system, the assembled battery tests the cycle performance under the conditions that the current is 0.05C and the charging and discharging voltage interval is 1.5-2.5V, and the cycle retention rate is 40.3% after 100 circles.
Comparative example 4
(1) Preparing a positive electrode and assembling a battery: as solid electrolyte Li6PS5Respectively weighing the materials Cl, elemental sulfur S, carbon fiber and binder PTFE in a mass ratio of 15:75:5:5, fully mixing and extruding and forming to obtain the self-made lithium-sulfur battery anode with single-side sulfurSurface loading of 4mg/cm2. The positive electrode and the solid electrolyte Li6PS5And assembling the lithium battery by the Cl and the metal lithium according to a conventional lamination process.
(2) And (3) testing the battery performance: by adopting the LAND test system, the assembled battery tests the cycle performance under the conditions that the current is 0.05C and the charging and discharging voltage interval is 1.5-2.5V, and the cycle retention rate is 37.3% after 100 circles.
Comparative example 5
(1) Preparing a positive electrode and assembling a battery: as solid electrolyte Li7P3S11Weighing the materials according to the mass ratio of elemental sulfur S, graphene and binder PTFE of 30:64:5:1, fully mixing and extruding to obtain the self-made lithium-sulfur battery anode with the single-side sulfur surface loading of 4mg/cm2. The positive electrode and the solid electrolyte Li7P3S11And assembling the lithium battery by the three according to a conventional lamination process.
(2) And (3) testing the battery performance: by adopting the LAND test system, the assembled battery tests the cycle performance under the conditions that the current is 0.05C and the charging and discharging voltage interval is 1.5-2.5V, and the cycle retention rate is 30.9% after 100 circles.
Therefore, the solid-state lithium-sulfur battery anode can effectively improve the specific capacity of sulfur and can effectively prolong the cycle life of the lithium-sulfur battery.

Claims (10)

1. A preparation method of a solid-state lithium-sulfur battery positive electrode is characterized by comprising the following steps:
(1) dissolving elemental sulfur in a solvent, adding a carbon carrier, and uniformly mixing to obtain a suspension; mixing a tetrahydrofuran solution of lithium triethylborohydride with the suspension, and drying to remove the solvent to obtain a first mixture of lithium sulfide and a carbon carrier; carrying out the step (2) or directly carrying out the step (3);
(2) adding the first mixture into a LiX solution, mixing, drying and removing a solvent to obtain a second mixture of lithium sulfide, LiX and a carbon carrier, wherein X is selected from one or more of Cl, Br and I;
(3) adding phosphorus pentasulfide into the first mixture or the second mixture obtained in the step (1) or the step (2), and heating to over 276 ℃ under a vacuum condition to obtain a third mixture of a lithium source, the phosphorus pentasulfide and a carbon carrier;
(4) roasting the third mixture obtained in the step (3) to obtain a fourth mixture of the solid electrolyte and the carbon carrier;
(5) adding a solution dissolved with elemental sulfur into the fourth mixture, mixing, and drying to remove the solvent to obtain a fifth mixture;
(6) and mixing the fifth mixture with a binder, and then carrying out extrusion forming to obtain the solid-state lithium-sulfur battery anode.
2. The method of claim 1, wherein the third mixture obtained in step (3) is ground before firing; preferably, the grinding is ball milling for 1-3 hours under vacuum condition.
3. The method of claim 1, wherein the solvent for dissolving elemental sulfur is one of carbon tetrachloride, benzene, acetone, chloroform, trichloroethylene, and carbon disulfide; preferably, the solvent is carbon disulfide.
4. The method of claim 1, wherein the firing is performed at 500 ℃ to 600 ℃ for 30 minutes to 1 hour under the protection of argon atmosphere.
5. The solid-state lithium-sulfur battery positive electrode is characterized by mainly comprising the following components in percentage by mass:
Figure FDA0003289438330000011
wherein the solid electrolyte is binary sulfide (Li)2S)a(P2S5)1-aOr ternary sulfides (Li)2S)b(P2S5)c(LiX)1-b-cX is selected from one or more of Cl, Br and I, a is more than 0 and less than 1, b is more than 0 and less than 1, c is more than 0 and less than 1, and b + c is more than 0 and less than 1.
6. The solid state lithium sulfur battery positive electrode of claim 5, wherein the solid electrolyte is Li3PS4、Li7P3S11、Li6PS5X is Cl, Br or I.
7. The solid-state lithium sulfur battery positive electrode of claim 5, wherein the carbon support is one of carbon fiber, carbon nanotubes, graphene carbon nanotube hybrid, activated carbon; preferably, the specific surface area of the carbon carrier is 10-1000 m2The pore diameter is 0.5-100 nm.
8. The solid-state lithium sulfur battery positive electrode of claim 5, wherein the binder is one of polyvinylpyrrolidone, polytetrafluoroethylene, polymethylmethacrylate, and polyethylene glycol.
9. The positive electrode of claim 5, wherein the single-sided sulfur surface loading of the positive electrode is 0.5-8 mg/cm2。
10. A solid-state lithium sulfur battery comprising the solid-state lithium sulfur battery positive electrode according to any one of claims 5 to 9.
CN202111159108.1A 2021-09-30 2021-09-30 Solid-state lithium-sulfur battery, battery positive electrode and preparation method thereof Pending CN113903882A (en)

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Publication number Priority date Publication date Assignee Title
CN104609376A (en) * 2015-01-30 2015-05-13 浙江工业大学 Preparation method of lithium sulfide powder
CN106784754A (en) * 2017-03-29 2017-05-31 中南大学 A kind of preparation method of CNT lithium sulfide carbon composite
US20170233250A1 (en) * 2014-08-12 2017-08-17 The Regents Of The University Of California Lithium sulfide-graphene oxide composite material for li/s cells
CN113036073A (en) * 2019-12-09 2021-06-25 中国科学院上海硅酸盐研究所 Composite positive electrode for solid-state lithium-sulfur battery and preparation method thereof

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20170233250A1 (en) * 2014-08-12 2017-08-17 The Regents Of The University Of California Lithium sulfide-graphene oxide composite material for li/s cells
CN104609376A (en) * 2015-01-30 2015-05-13 浙江工业大学 Preparation method of lithium sulfide powder
CN106784754A (en) * 2017-03-29 2017-05-31 中南大学 A kind of preparation method of CNT lithium sulfide carbon composite
CN113036073A (en) * 2019-12-09 2021-06-25 中国科学院上海硅酸盐研究所 Composite positive electrode for solid-state lithium-sulfur battery and preparation method thereof

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