CN111559740A - Preparation method of solid electrolyte with air gap - Google Patents

Preparation method of solid electrolyte with air gap Download PDF

Info

Publication number
CN111559740A
CN111559740A CN202010473817.6A CN202010473817A CN111559740A CN 111559740 A CN111559740 A CN 111559740A CN 202010473817 A CN202010473817 A CN 202010473817A CN 111559740 A CN111559740 A CN 111559740A
Authority
CN
China
Prior art keywords
latp
aao template
air gap
solid electrolyte
precursor solution
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
CN202010473817.6A
Other languages
Chinese (zh)
Other versions
CN111559740B (en
Inventor
孙建敏
郜蒙蒙
白莹
赵慧玲
郁彩艳
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Henan University
Original Assignee
Henan University
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Henan University filed Critical Henan University
Priority to CN202010473817.6A priority Critical patent/CN111559740B/en
Publication of CN111559740A publication Critical patent/CN111559740A/en
Application granted granted Critical
Publication of CN111559740B publication Critical patent/CN111559740B/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

Classifications

    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B25/00—Phosphorus; Compounds thereof
    • C01B25/16—Oxyacids of phosphorus; Salts thereof
    • C01B25/26—Phosphates
    • C01B25/45—Phosphates containing plural metal, or metal and ammonium
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B82—NANOTECHNOLOGY
    • B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
    • B82Y30/00—Nanotechnology for materials or surface science, e.g. nanocomposites
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B82—NANOTECHNOLOGY
    • B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
    • B82Y40/00—Manufacture or treatment of nanostructures
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/056—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes
    • H01M10/0561—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes the electrolyte being constituted of inorganic materials only
    • H01M10/0562—Solid materials
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/058—Construction or manufacture
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/42—Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells
    • H01M10/4235—Safety or regulating additives or arrangements in electrodes, separators or electrolyte
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2006/00—Physical properties of inorganic compounds
    • C01P2006/40—Electric properties
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
    • Y02P70/50—Manufacturing or production processes characterised by the final manufactured product

Landscapes

  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Nanotechnology (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Condensed Matter Physics & Semiconductors (AREA)
  • General Physics & Mathematics (AREA)
  • Physics & Mathematics (AREA)
  • Organic Chemistry (AREA)
  • Inorganic Chemistry (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Materials Engineering (AREA)
  • Composite Materials (AREA)
  • Inert Electrodes (AREA)
  • Hybrid Cells (AREA)

Abstract

The invention provides a preparation method of a solid electrolyte with an air gap, which avoids serious side reaction caused by direct contact between LATP and a lithium metal cathode. The invention absorbs a proper amount of LATP through the absorbent paper, so that the LATP lithium ions injected into the holes of the double-pass AAO template are properly lost, and a proper length of the rapid conduction path of the LATP lithium ions and a proper gap size are obtained. The air gap can avoid side reactions caused by contact of LATP with the negative electrode lithium metal and can ensure transition transport of lithium ions.

Description

Preparation method of solid electrolyte with air gap
Technical Field
The invention relates to a preparation method of a solid electrolyte in a lithium battery, in particular to a method for preparing a solid electrolyte with an air gap in a bi-pass AAO template.
Background
In recent years, LATP in solid electrolytes has been attracting attention because of its high lithium ion conductivity, resulting in high ionic conductivity due to: (1) the aluminum ions are partially doped in the LTP framework, so that the crystal boundary energy barrier can be effectively reduced through structural change and subsequent densification; (2) the doping of Al not only enhances the mobility of lithium ions, promotes the diffusion capability of the lithium ions on different interfaces, but also reduces the activation energy.
However, the direct contact between LATP and the negative electrode of lithium metal, which converts Ti in LATP, causes serious side reactions4+Reduction to Ti3+Not only the LATP structure is made unstable, but also the products of the side reaction are accumulated at the interface, which leads to the decrease of the SSE grain boundary ionic conductivity.
Disclosure of Invention
To solve the above technical problem, the present invention provides a continuous conductive LATP solid-state electrolyte with air gaps. The air gap can avoid side reaction caused by the contact of LATP and lithium metal of the negative electrode and ensure the transition transmission of lithium ions. The subject group has obtained the proper gap distance by controlling the amount of injected LATP through a vacuum injection method, but the above method requires special injection equipment, and the amount control is precise, and the process difficulty is large.
The technical solution of the invention is as follows:
a continuous conduction LATP solid electrolyte is characterized in that LATP nano-particles grow densely from one end of a bi-pass AAO template to the other end along the inner wall of a hole of the AAO template to form a continuous lithium ion rapid conduction path, so that the ionic conductivity can be obviously improved, and the LATP nano-particles are uniform in particle size and 20-30nm in diameter; the LATP nano-particles do not completely fill the pore diameter of the AAO template, and the distance between the length of the rapid lithium ion conduction path and the other end is 10-50 nm; the other end of the AAO template is in direct contact with a lithium metal negative electrode, and a 10-50nm gap can avoid side reactions caused by contact of LATP and negative electrode lithium metal and ensure transition transmission of lithium ions.
A lithium ion battery using a continuous conduction LATP solid electrolyte is characterized in that an LATP nanowire using an AAO template as a framework is arranged between a positive electrode and a lithium metal negative electrode, wherein one end of the AAO template is directly contacted with the positive electrode, the other end of the AAO template is directly contacted with the lithium metal negative electrode, one end of the LATP nanowire in the pore diameter of the AAO template is directly contacted with the positive electrode, and an air gap of 10-50nm directly exists between the other end of the LATP nanowire and the lithium metal negative electrode.
A method for preparing a solid electrolyte with an air gap comprises the following steps:
step 1, preparation of LATP (Li)1.4Al0.4Ti1.6(PO4)3) Precursor solution;
step 2, double-pass AAO template pretreatment: heating the AAO template under normal pressure, removing water vapor and impurities in the bi-pass AAO template, and cooling;
step 3, full-soaking and then full-capillary adsorption: fully immersing the bi-pass AAO template obtained in the step 2 into the LATP precursor solution prepared in the step 1 for 1-2 hours to ensure that the holes of the bi-pass AAO template are fully adsorbed with the LATP precursor solution;
and 4, sucking a proper amount of LATP in the bi-pass AAO template by the absorbent paper, namely, horizontally placing the bi-pass AAO template with the orifices fully absorbing the LATP precursor solution on the absorbent paper for a certain time upwards.
And 5, annealing: annealing the dual pass AAO template processed in step 4 above to obtain a continuous conductive LATP solid electrolyte with an air gap at one end.
Preferably, the length of the air gap is 10-50 nm.
Preferably, the holding time is 2 to 10 seconds.
The invention has the beneficial effects that:
a continuous conductive LATP solid electrolyte and a preparation method thereof and a lithium ion battery using the same are provided, which avoid serious side reactions caused by direct contact between LATP and a lithium metal cathode. According to the invention, a proper amount of LATP is absorbed by the absorbent paper, so that the LATP injected into the holes of the double-pass AAO template is properly lost, and a proper length of LATP lithium ion rapid conduction path and a proper gap size are obtained.
Drawings
The invention is further described below with reference to the accompanying drawings.
FIG. 1 is a flow chart of a method of preparing a solid electrolyte with air gaps according to the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the following embodiments are further described in detail. It should be understood that the specific embodiments described herein are merely illustrative of the invention and that the invention is not limited in this regard.
[ examples ]
A method for preparing a solid electrolyte with an air gap comprises the following steps:
step 1, preparation of Li1.4Al0.4Ti1.6(PO4)3Precursor solution; respectively dissolving lithium nitrate, aluminum nitrate nonahydrate and phosphoric acid in 5ml of absolute ethyl alcohol according to stoichiometric ratio, dropwise adding a small amount of nitric acid to prevent hydrolysis of the aluminum nitrate nonahydrate, stirring for 30min, and dropwise adding the lithium nitrate into the aluminum nitrate nonahydrate, wherein the obtained solution is marked as solution A. Dissolving isopropyl titanate in 5ml of absolute ethyl alcohol according to a stoichiometric ratio, slowly dripping the solution A into the isopropyl titanate to obtain a solution B, and finally dripping phosphoric acid into the solution B to obtain a solution, namely the prepared LATP precursor solution.
Step 2, preprocessing an AAO template: weighing a certain mass of AAO template, removing water vapor and impurities under a heating state at 200 ℃, and cooling.
Step 3, fully immersing the bi-pass AAO template obtained in the step 2 into the LATP precursor solution prepared in the step 1 for 1-2 hours to ensure that the holes of the bi-pass AAO template are fully adsorbed with the LATP precursor solution;
and 4, sucking a proper amount of LATP in the bi-pass AAO template by the absorbent paper, and horizontally placing the bi-pass AAO template with the orifices fully absorbing the LATP precursor solution on the absorbent paper for a certain time in an upward mode.
Step 5, 500-600 times of nitrogen atmosphereoAnd C, calcining the AAO template injected with a proper amount of LATP precursor solution for 4-6 hours, and then cooling.
Step 6, 750 again in nitrogen atmosphereoC-800oCalcining for 15h under C to improve the uniformity of the particle size of the LATP nano particles, naturally cooling and taking out to obtain the continuous conduction solid electrolyte with air gaps in the AAO template pore canal at a distance of 10-50nm from the top. The size of the air gap is related to the retention time and the adsorption force of the absorbent paper. Taking the pure wood pulp absorbent paper produced by Loxowo shuerlai paper products Co., Ltd as an example, the test data are as follows:
Figure DEST_PATH_IMAGE002
。

Claims (8)

1. a method for preparing solid electrolyte with air gap is characterized in that,
step 1, preparation of LATP (Li)1.4Al0.4Ti1.6(PO4)3) Precursor solution;
step 2, pretreating a bi-pass AAO template, heating the AAO template under normal pressure, removing water vapor and impurities in the bi-pass AAO template, and cooling;
step 3, fully absorbing through capillary action after full immersion, fully immersing the bi-pass AAO template obtained in the step 2 into the LATP precursor solution prepared in the step 1, and ensuring that holes of the bi-pass AAO template are fully absorbed with the LATP precursor solution;
step 4, absorbing a proper amount of LATP in the bi-pass AAO template by absorbent paper, and horizontally placing the bi-pass AAO template with the LATP precursor solution absorbed thereon for a certain time with the orifice facing upwards;
and 5, annealing, namely annealing the double-pass AAO template treated in the step 4 to obtain the continuous conductive LATP solid electrolyte with an air gap at one end.
2. The method of claim 1, wherein the AAO template has an air gap at one end in contact with the lithium metal negative electrode.
3. The method of claim 2, wherein the length of the air gap is 10 to 50 nm.
4. The method for producing a solid electrolyte having an air gap according to claim 3, wherein the holding time is 2 to 10 seconds.
5. The method for preparing a solid electrolyte with an air gap according to claim 3, wherein the time of the full immersion in the step 3 is 1 to 2 hours.
6. The method of claim 3, wherein the annealing in step 5 is an in-situ second annealing, and the second annealing temperature is higher than the first annealing temperature.
7. A method for preparing a solid electrolyte with an air gap comprises the following steps:
step 1, preparation of Li1.4Al0.4Ti1.6(PO4)3Precursor solution; respectively dissolving lithium nitrate, aluminum nitrate nonahydrate and phosphoric acid in 5ml of absolute ethyl alcohol according to a stoichiometric ratio, dropwise adding a small amount of nitric acid to prevent the aluminum nitrate nonahydrate from being hydrolyzed, stirring for 30min, and dropwise adding the lithium nitrate into the aluminum nitrate nonahydrate, wherein the obtained solution is marked as solution A; dissolving isopropyl titanate in 5ml of absolute ethyl alcohol according to a stoichiometric ratio, slowly dripping the solution A into the isopropyl titanate to obtain a solution B, and finally dripping phosphoric acid into the solution B to obtain a solution, namely the prepared LATP precursor solution;
step 2, preprocessing an AAO template: weighing AAO template with certain mass at 200oRemoving water vapor and impurities in a heating state, and cooling;
step 3, fully immersing the bi-pass AAO template obtained in the step 2 into the LATP precursor solution prepared in the step 1 for 1-2 hours to ensure that the holes of the bi-pass AAO template are fully adsorbed with the LATP precursor solution;
step 4, absorbing a proper amount of LATP in the bi-pass AAO template by absorbent paper, and horizontally placing the bi-pass AAO template with the LATP precursor solution absorbed thereon for a certain time with the orifice facing upwards;
step 5, 500-600 times of nitrogen atmosphereoC, calcining the AAO template injected with a proper amount of LATP precursor solution for 4-6 hours, and then cooling;
step 6, 750-800 times in the nitrogen atmosphereoCalcining for 15h under C to improve the uniformity of the particle size of the LATP nano particles, and taking out after natural cooling to obtain the continuous conduction solid electrolyte with air gaps in the AAO template pore channels 10-50nm away from the top.
8. A lithium ion battery using a continuous conductive LATP solid electrolyte, characterized in that between the positive electrode and the lithium metal negative electrode is an air gap solid electrolyte prepared using the method of any one of claims 1-7, wherein one end of the air gap solid electrolyte is in contact with the positive electrode and the other end having an air gap is in direct contact with the lithium metal negative electrode.
CN202010473817.6A 2020-05-29 2020-05-29 Preparation method of solid electrolyte with air gap Active CN111559740B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202010473817.6A CN111559740B (en) 2020-05-29 2020-05-29 Preparation method of solid electrolyte with air gap

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202010473817.6A CN111559740B (en) 2020-05-29 2020-05-29 Preparation method of solid electrolyte with air gap

Publications (2)

Publication Number Publication Date
CN111559740A true CN111559740A (en) 2020-08-21
CN111559740B CN111559740B (en) 2023-01-24

Family

ID=72073691

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202010473817.6A Active CN111559740B (en) 2020-05-29 2020-05-29 Preparation method of solid electrolyte with air gap

Country Status (1)

Country Link
CN (1) CN111559740B (en)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114094273A (en) * 2021-10-22 2022-02-25 上海空间电源研究所 Thermal battery isolation layer with anti-overflow function and preparation method thereof
CN114804055A (en) * 2022-05-16 2022-07-29 广东凯金新能源科技股份有限公司 Solid electrolyte with high density and small size and preparation method thereof
WO2024065192A1 (en) * 2022-09-27 2024-04-04 宁德时代新能源科技股份有限公司 Solid-state electrolyte and preparation method therefor, positive electrode sheet and preparation method therefor, battery, and electrical device

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN104282930A (en) * 2013-07-10 2015-01-14 中国科学院大连化学物理研究所 Molten carbonate fuel cell structure
US20170288263A1 (en) * 2014-09-05 2017-10-05 Forschungszentrum Juelich Gmbh Solid-state electrolytes for lithium batteries and process for production thereof

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN104282930A (en) * 2013-07-10 2015-01-14 中国科学院大连化学物理研究所 Molten carbonate fuel cell structure
US20170288263A1 (en) * 2014-09-05 2017-10-05 Forschungszentrum Juelich Gmbh Solid-state electrolytes for lithium batteries and process for production thereof

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114094273A (en) * 2021-10-22 2022-02-25 上海空间电源研究所 Thermal battery isolation layer with anti-overflow function and preparation method thereof
CN114094273B (en) * 2021-10-22 2024-04-19 上海空间电源研究所 Thermal battery isolation layer with overflow prevention function and preparation method thereof
CN114804055A (en) * 2022-05-16 2022-07-29 广东凯金新能源科技股份有限公司 Solid electrolyte with high density and small size and preparation method thereof
WO2024065192A1 (en) * 2022-09-27 2024-04-04 宁德时代新能源科技股份有限公司 Solid-state electrolyte and preparation method therefor, positive electrode sheet and preparation method therefor, battery, and electrical device

Also Published As

Publication number Publication date
CN111559740B (en) 2023-01-24

Similar Documents

Publication Publication Date Title
CN111559740B (en) Preparation method of solid electrolyte with air gap
CN112582615B (en) One-dimensional porous silicon-carbon composite negative electrode material, preparation method and application thereof
CN111682173B (en) Composite material of multi-heteroatom co-doped carbon shell coated silicon and preparation method thereof
CN109326768B (en) Sodium ion battery cathode, preparation method thereof and sodium ion battery
CN107768637B (en) Preparation method of porous graphene/carbon nanotube lithium-sulfur positive electrode material
CN109850886B (en) Porous graphite material and preparation method and application thereof
CN113161528A (en) Preparation method of double-layer composite silicon-coated material and lithium ion battery thereof
CN113921762A (en) Nano bismuth composite material and preparation method and application thereof
CN114530601A (en) Preparation method of boron-doped porous carbon material and application of boron-doped porous carbon material in potassium ion battery
CN114023948B (en) Silicon-carbon negative electrode material, preparation method thereof and lithium ion battery
CN111725493A (en) Modified niobium-titanium oxide and preparation method and application thereof
CN115036471A (en) Silicon-based composite material and preparation method thereof, negative electrode material of lithium battery and preparation method thereof, and lithium battery
CN107946559B (en) Sb for solvothermal preparation of sodium ion battery cathode2Se3Method for preparing/C composite material
CN115863660B (en) Negative electrode current collector of non-negative electrode lithium battery and preparation method and application thereof
CN108892123B (en) Preparation method of porous graphene
CN115332485A (en) Composite lithium metal negative electrode, preparation method thereof and lithium metal battery
CN106033817B (en) Amberplex, preparation method and the application of nano array structure
CN111573649B (en) Preparation method of atomic size gap in bi-pass AAO template solid electrolyte
CN111261856B (en) Carbon sheet cage coated porous silicon material and preparation method and application thereof
CN110902660B (en) Preparation method of GaN nanowire lithium ion battery cathode material
CN111313020A (en) Preparation method of sulfur-doped nitrogen-rich carbon material, electrode and application of sulfur-doped nitrogen-rich carbon material in sodium/potassium ion battery
CN111048776A (en) Morphology-adjustable cubic cobaltosic oxide, preparation method thereof and lithium ion battery
CN117509733B (en) ZnMoO3/C microsphere with intrinsic Zn defect core-shell structure and preparation method and application thereof
CN116598617B (en) Lithium metal composite negative electrode, preparation method thereof and battery
CN116031495A (en) Sulfide all-solid-state battery based on composite negative electrode and preparation method thereof

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination
GR01 Patent grant
GR01 Patent grant