Preparation method of all-solid-state lithium-sulfur battery positive electrode material based on multifunctional metal oxide carrier

Abstract

The invention provides a preparation method of an all-solid-state lithium-sulfur battery positive electrode material based on a multifunctional metal oxide carrier. The preparation method of the positive electrode material comprises the following steps: mixing and grinding a metal oxide and elemental sulfur according to a certain proportion; feeding the ground mixture into a hydrothermal reaction kettle, and keeping the temperature for a period of time at high temperature; and mixing the obtained sulfur-loaded metal oxide with a conductive agent and a solid electrolyte according to a certain proportion, and then feeding into a ball mill for ball milling for a certain time to obtain the solid lithium-sulfur battery positive electrode material based on the sulfur-loaded metal oxide. The metal oxide disclosed by the invention has good electronic conductivity, and is combined with the conductive additive, so that a continuous electron conduction path can be formed among sulfur particles; the metal oxide has a catalytic effect on the oxidation-reduction process of sulfur, so that the oxidation-reduction motive power of the sulfur can be accelerated; the shuttle effect is eliminated by the matched inorganic solid electrolyte; the all-solid-state lithium-sulfur battery based on the metal oxide sulfur-loaded positive electrode material has high performance and high energy density.

Description

Technical Field

[0001] The invention relates to the technical field of battery positive electrode materials, and in particular to a method for preparing an all-solid-state lithium-sulfur battery positive electrode material based on a multifunctional metal oxide carrier. Background Art

[0002] Based on the ideal theoretical specific capacity (1675 mAh g -1 ), high energy density (2600Wh kg -1 ), low cost and abundant resource reserves, lithium-sulfur batteries are considered to be one of the most promising energy storage systems.

[0003] However, the development of lithium-sulfur batteries has been greatly restricted by the use of flammable and leaky organic electrolytes in traditional lithium-sulfur batteries, as well as the shuttle effect caused by polysulfides and lithium dendrites caused by lithium metal anodes. All-solid-state lithium-sulfur batteries that use non-flammable and mechanically strong solid electrolytes can effectively solve the above problems in traditional lithium-sulfur batteries and are considered to be the ideal choice for the next generation of energy storage batteries.

[0004] However, due to the low ionic / electronic conductivity of sulfur in all-solid-state lithium-sulfur batteries and the lack of polysulfide conversion in all-solid-state lithium-sulfur batteries using inorganic solid-state electrolytes, the redox kinetics of the sulfur positive electrode are slow, while the use of polymer solid-state electrolytes will lead to the occurrence of polysulfide shuttle effect. These problems have seriously hindered the development and practical application of all-solid-state lithium-sulfur batteries.

[0005] In order to solve the problem of low electronic conductivity of sulfur, a large amount of carbon is usually added to the cathode composite material of all-solid-state lithium-sulfur batteries as a conductive carrier and conductive additive. The positive electrode of the all-solid-state lithium-sulfur battery usually uses porous carbon, carbon nanotubes (CNT) / fibers, graphene and other carbon materials as a conductive substrate to encapsulate sulfur, which can not only improve the conductivity of the sulfur positive electrode, but also buffer the volume changes during lithiation and delithiation. However, carbon materials cannot solve the problem of slow kinetics caused by solid-solid conversion, so the existing technology also requires the addition of catalysts to accelerate the conversion of sulfur active species, but this usually leads to additional cost increases and reduced battery energy density. Summary of the invention

[0006] In view of the deficiencies in the prior art, the present invention provides a method for preparing an all-solid-state lithium-sulfur battery positive electrode material based on a multifunctional metal oxide carrier. The present invention can accelerate the redox kinetics of sulfur, eliminate the shuttle effect, and form a continuous electron conduction path between sulfur particles.

[0007] The technical solution of the present invention is: a method for preparing a positive electrode material for an all-solid-state lithium-sulfur battery based on a multifunctional metal oxide carrier, comprising the following steps:

[0008] S1), mixing metal oxide and sulfur in a certain proportion and grinding for 20 to 40 minutes;

[0009] S2), the mixture obtained in step S1) is sent into a hydrothermal reactor and kept warm at high temperature for a period of time;

[0010] S3), mixing the metal oxide-supported sulfur obtained in step S2) with a conductive agent and a solid electrolyte in a certain proportion, and then sending the mixture into a ball mill for ball milling for a certain period of time to obtain a solid lithium-sulfur battery positive electrode material based on metal oxide-supported sulfur;

[0011] S4), taking a certain amount of solid-state lithium-sulfur battery positive electrode material based on metal oxide-supported sulfur, placing it on the current collector, dispersing it evenly and compacting it; obtaining a solid-state lithium-sulfur battery positive electrode based on metal oxide-supported sulfur.

[0012] Preferably, in step S1), the metal oxide is Ti 2 O 3 、Co 3 O 4 、TiO、TiO 2 , Fe 3 O 4 ,FeO,Fe 2 O 3 , CoO, Co 2 O 3 , NiO, Ni 2 O 3 , NiO 2 , MnO, Mn 2 O 3 , MnO 2 ,Mn 3 O 4 A mixture of one or more of the above.

[0013] Preferably, in step S1), the mass ratio of the metal oxide to sulfur is 3:2.

[0014] Preferably, in step S2), the reactor is heated to 155° C. and the high temperature insulation time is 10 to 14 hours.

[0015] Preferably, in step S3), the mass ratio of the metal oxide-supported sulfur to the conductive agent and the solid electrolyte is 5:2:3.

[0016] Preferably, in step S3), the ball milling time is 8 to 12 hours.

[0017] Preferably, in step S3), the ball milling time is 12 hours.

[0018] Preferably, in step S3), the conductive agent is Super p.

[0019] Preferably, in step S3), the solid electrolyte is Li 7 P 3 S 11 .

[0020] Preferably, in step S3), the material of the current collector includes at least one of aluminum, boron, gold, silver, platinum, carbon, iron, titanium, nickel, and stainless steel.

[0021] Preferably, the present invention also provides an all-solid-state lithium-sulfur battery, comprising a positive electrode, a negative electrode and a solid electrolyte, wherein the positive electrode is a solid-state lithium-sulfur battery positive electrode material of metal oxide-supported sulfur prepared by the above steps.

[0022] Preferably, the solid electrolyte is a mixture of one or more of a polymer electrolyte, an inorganic solid electrolyte and a composite electrolyte.

[0023] Preferably, the negative electrode is a lithium metal negative electrode or an alloy negative electrode.

[0024] The beneficial effects of the present invention are:

[0025] 1. The metal oxide of the present invention has good electronic conductivity and can form a continuous electronic conduction path between sulfur particles when combined with a conductive additive;

[0026] 2. The metal oxide of the present invention has a catalytic effect on the oxidation-reduction process of sulfur, which can accelerate the oxidation-reduction dynamics of sulfur; the inorganic solid electrolyte matched therewith eliminates the shuttle effect;

[0027] 3. The all-solid-state lithium-sulfur battery based on the metal oxide-supported sulfur solid-state lithium-sulfur battery positive electrode material of the present invention has high performance and high energy density. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is a cycle performance diagram of an all-solid-state lithium-sulfur battery assembled using metal oxide-supported sulfur as the positive electrode material at 50° C. and 0.1C current density in Example 6 of the present invention;

[0029] Figure 2 This is a cycle performance diagram of an all-solid-state lithium-sulfur battery assembled using metal oxide-supported sulfur as the positive electrode material at room temperature and a current density of 0.1C in Example 6 of the present invention;

[0030] Figure 3 This is a cycle performance diagram of an all-solid-state lithium-sulfur battery assembled using metal oxide-supported sulfur as the positive electrode material at 50° C. and 0.5C current density in Example 6 of the present invention;

[0031] Figure 4 This is a rate performance diagram of an all-solid-state lithium-sulfur battery assembled using metal oxide-supported sulfur as the positive electrode material at 50°C in Example 6 of the present invention. DETAILED DESCRIPTION

[0032] The specific implementation of the present invention will be further described below in conjunction with the accompanying drawings:

[0033] Example 1

[0034] This embodiment provides a method for preparing a positive electrode material for an all-solid-state lithium-sulfur battery based on a multifunctional metal oxide carrier, comprising the following steps:

[0035] S1), metal oxide Ti 2 O 3 Mix with sulfur in a mass ratio of 3:2 and grind for 20 to 40 minutes;

[0036] S2), the mixture obtained in step S1) is sent to a hydrothermal reactor and kept at 155°C for 12 hours to obtain S@Ti 2 O 3 ;

[0037] S3), the S@Ti obtained in step S2) 2 O 3 With conductive agent Super p and Li 7 P 3 S 11 The solid electrolytes were mixed in a mass ratio of 5:2:3 and then sent into a ball mill for 12 hours to obtain S@Ti based 2 O 3 Solid-state lithium-sulfur battery cathode materials;

[0038] S4), then take 0.5-1.5 mg based on S@Ti 2 O 3 The solid-state lithium-sulfur battery positive electrode material is evenly dispersed and compacted on the carbon-coated aluminum foil to obtain S@Ti 2 O 3 Solid-state lithium-sulfur battery positive electrode.

[0039] Example 2

[0040] This embodiment provides a method for preparing a positive electrode material for an all-solid-state lithium-sulfur battery based on a multifunctional metal oxide carrier, comprising the following steps:

[0041] S1), metal oxide Co 3 O 4 Mix with sulfur in a mass ratio of 3:2 and grind for 20 to 40 minutes;

[0042] S2) The mixture obtained in step S1) is sent to a hydrothermal reactor and kept at 155°C for 12 hours to obtain S@Co 3 O 4 ;

[0043] S3), the S@Co obtained in step S2) 3 O 4 With conductive agent Super p and Li 7 P 3 S 11 The solid electrolytes were mixed in a mass ratio of 5:2:3 and then sent into a ball mill for 12 hours to obtain S@Co 3 O 4 Solid-state lithium-sulfur battery cathode materials;

[0044] S4), then take 0.5-1.5 mg based on S@Co 3 O 4 The solid-state lithium-sulfur battery cathode material is evenly dispersed and compacted on the carbon-coated aluminum foil to obtain S@Co 3 O 4 Solid-state lithium-sulfur battery positive electrode.

[0045] Example 3

[0046] This embodiment provides a method for preparing a positive electrode material for an all-solid-state lithium-sulfur battery based on a multifunctional metal oxide carrier, comprising the following steps:

[0047] S1), mixing metal oxide NiO and sulfur in a mass ratio of 3:2 and grinding for 20 to 40 minutes;

[0048] S2), the mixture obtained in step S1) is sent into a hydrothermal reactor and kept at 155° C. for 12 hours to obtain S@NiO;

[0049] S3), the S@NiO obtained in step S2) is mixed with the conductive agent Super p and Li 7 P 3 S 11 The solid electrolytes were mixed in a mass ratio of 5:2:3 and then sent into a ball mill for 12 hours to obtain a solid-state lithium-sulfur battery positive electrode material based on S@NiO;

[0050] S4), then take 0.5-1.5 mg of S@NiO-based solid-state lithium-sulfur battery positive electrode material and place it on the carbon-coated aluminum foil, disperse it evenly and compact it to obtain the S@NiO solid-state lithium-sulfur battery positive electrode.

[0051] Example 4

[0052] This embodiment provides a method for preparing a positive electrode material for an all-solid-state lithium-sulfur battery based on a multifunctional metal oxide carrier, comprising the following steps:

[0053] S1), mixing metal oxide FeO and sulfur in a mass ratio of 3:2 and grinding for 20 to 40 minutes;

[0054] S2), the mixture obtained in step S1) is sent to a hydrothermal reactor and kept at 155°C for 12 hours to obtain S@FeO;

[0055] S3), the S@FeO obtained in step S2) is mixed with the conductive agent Super p and Li 7 P 3 S 11 The solid electrolytes were mixed in a mass ratio of 5:2:3, and then sent into a ball mill for 12 hours to obtain a solid-state lithium-sulfur battery positive electrode material based on S@FeO;

[0056] S4), then take 0.5-1.5 mg of S@FeO-based solid-state lithium-sulfur battery positive electrode material and place it on the carbon-coated aluminum foil, disperse it evenly and compact it to obtain a S@FeO solid-state lithium-sulfur battery positive electrode.

[0057] Example 5

[0058] This embodiment provides a method for preparing a positive electrode material for an all-solid-state lithium-sulfur battery based on a multifunctional metal oxide carrier, comprising the following steps:

[0059] S1), metal oxide Mn 2 O 3 Mix with sulfur in a mass ratio of 3:2 and grind for 20 to 40 minutes;

[0060] S2), the mixture obtained in step S1) is sent to a hydrothermal reactor and kept at 155°C for 12 hours to obtain S@Mn 2 O 3 ;

[0061] S3), the S@Mn obtained in step S2) 2 O 3 With conductive agent Super p and Li 7 P 3 S 11 The solid electrolytes were mixed in a mass ratio of 5:2:3 and then sent into a ball mill for 12 hours to obtain S@Mn based 2 O 3 Solid-state lithium-sulfur battery cathode materials;

[0062] S4), then take 0.5-1.5 mg based on S@Mn 2 O 3 The solid-state lithium-sulfur battery cathode material is evenly dispersed and compacted on the carbon-coated aluminum foil to obtain S@Mn 2 O 3Solid-state lithium-sulfur battery positive electrode.

[0063] Example 6

[0064] This embodiment provides an all-solid-state lithium-sulfur battery. This embodiment uses the S@Ti prepared in Example 1. 2 O 3 The positive electrode uses lithium metal as the negative electrode, and the solid electrolyte uses an inorganic solid electrolyte Li 7 P 3 S 11 Assembling all-solid-state lithium-sulfur batteries.

[0065] Example 7

[0066] This example performs a performance test on the all-solid-state lithium-sulfur battery assembled in Example 6, as follows:

[0067] like Figure 1 As shown, the all-solid-state lithium-sulfur battery of Example 6 was tested for long cycle stability at 50°C and 0.1C rate. Figure 1 It can be seen that at 50°C and 0.1C rate, the all-solid-state lithium-sulfur battery of Example 6 has a high specific capacity (>1500mAh g -1 ) and excellent cycle stability.

[0068] like Figure 2 As shown, the all-solid-state lithium-sulfur battery of Example 6 was tested for long cycle stability at room temperature and 0.1C rate. Figure 2 It can be seen that at room temperature and 0.1C rate, the all-solid-state lithium-sulfur battery of Example 6 still has a high specific capacity and excellent cycle stability.

[0069] like Figure 3 As shown, the all-solid-state lithium-sulfur battery of Example 6 was tested for long cycle stability at 50°C and 0.5C rate. Figure 3 It can be seen that at 50°C and 0.5C rate, the all-solid-state lithium-sulfur battery of Example 6 still has a high specific capacity and excellent cycle stability.

[0070] like Figure 4 As shown, the rate performance test of the all-solid-state lithium-sulfur battery of Example 6 was carried out at 50°C. Figure 4 It can be seen that at 50°C, the all-solid-state lithium-sulfur battery of Example 6 has excellent rate performance.

[0071] The above embodiments and descriptions are only for illustrating the principles and best embodiments of the present invention. Without departing from the spirit and scope of the present invention, the present invention may be subject to various changes and improvements, all of which fall within the scope of the present invention to be protected.

Claims

1. A method for preparing a positive electrode material for an all-solid-state lithium-sulfur battery based on a multifunctional metal oxide carrier, characterized in that: The following steps are involved: S1), mixing metal oxide and sulfur in a certain proportion and grinding for 20 to 40 minutes; S2), sending the mixture obtained in step S1) into a hydrothermal reactor and keeping it warm for a period of time at high temperature; S3), mixing the metal oxide-supported sulfur obtained in step S2) with a conductive agent and a solid electrolyte in a certain proportion, and then sending them into a ball mill for a certain period of time to obtain a solid lithium-sulfur battery positive electrode material based on metal oxide-supported sulfur.

2. The method for preparing an all-solid-state lithium-sulfur battery positive electrode material based on a multifunctional metal oxide carrier according to claim 1, characterized in that: In step S1), the mass ratio of the metal oxide to the sulfur element is 3:

2.

3. The method for preparing an all-solid-state lithium-sulfur battery positive electrode material based on a multifunctional metal oxide carrier according to claim 2, characterized in that: In step S1), the metal oxide is a mixture of one or more of Ti2O3, Co3O4, TiO, TiO2, Fe3O4, FeO, Fe2O3, CoO, Co2O3, NiO, Ni2O3, NiO2, MnO, Mn2O3, MnO2, and Mn3O4.

4. The method for preparing an all-solid-state lithium-sulfur battery positive electrode material based on a multifunctional metal oxide carrier according to claim 1, characterized in that: In step S2), the temperature of the reactor heating is 155°C; The high temperature insulation time is 10 to 14 hours.

5. The method for preparing an all-solid-state lithium-sulfur battery positive electrode material based on a multifunctional metal oxide carrier according to claim 1, characterized in that: In step S3), the mass ratio of the metal oxide-supported sulfur to the conductive agent and the solid electrolyte is 5:2:

3.

6. The method for preparing an all-solid-state lithium-sulfur battery positive electrode material based on a multifunctional metal oxide carrier according to claim 5, characterized in that: In step S3), the ball milling time is 8 to 12 hours.

7. The method for preparing an all-solid-state lithium-sulfur battery positive electrode material based on a multifunctional metal oxide carrier according to claim 5, characterized in that: In step S3), the conductive agent is Super p.

8. The method for preparing an all-solid-state lithium-sulfur battery positive electrode material based on a multifunctional metal oxide carrier according to claim 5, characterized in that: In step S3), the solid electrolyte is Li7P3S 11 .

9. An all-solid-state lithium-sulfur battery, comprising a positive electrode, a negative electrode and a solid electrolyte, characterized in that: The positive electrode is a solid-state lithium-sulfur battery positive electrode material containing sulfur supported by a metal oxide prepared by the method described in claims 1-8.

10. The battery according to claim 9, characterized in that: The solid electrolyte is a mixture of one or more of a polymer electrolyte, an inorganic solid electrolyte and a composite electrolyte; the negative electrode is a lithium metal negative electrode or an alloy negative electrode.

Images