CN114552129B - Double-sided differential lithium battery diaphragm and lithium battery comprising same - Google Patents
Double-sided differential lithium battery diaphragm and lithium battery comprising same Download PDFInfo
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- CN114552129B CN114552129B CN202110792546.5A CN202110792546A CN114552129B CN 114552129 B CN114552129 B CN 114552129B CN 202110792546 A CN202110792546 A CN 202110792546A CN 114552129 B CN114552129 B CN 114552129B
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
- H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
- H01M50/409—Separators, membranes or diaphragms characterised by the material
- H01M50/449—Separators, membranes or diaphragms characterised by the material having a layered structure
- H01M50/457—Separators, membranes or diaphragms characterised by the material having a layered structure comprising three or more layers
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- 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
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
- H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
- H01M50/403—Manufacturing processes of separators, membranes or diaphragms
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
- H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
- H01M50/46—Separators, membranes or diaphragms characterised by their combination with electrodes
- H01M50/461—Separators, membranes or diaphragms characterised by their combination with electrodes with adhesive layers between electrodes and separators
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- Y02E60/10—Energy storage using batteries
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- 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
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Abstract
The invention relates to the field of lithium batteries, and discloses a double-sided differential lithium battery diaphragm and a lithium battery containing the same, wherein the double-sided differential lithium battery diaphragm comprises a polymer base film, and a positive electrode attaching coating and a negative electrode attaching coating which are respectively coated on two sides of the polymer base film; the positive electrode attaching coating and the negative electrode attaching coating both comprise polymer adhesive and inorganic material particles, and the adhesive force of the positive electrode attaching coating is smaller than that of the negative electrode attaching coating; the inorganic material particles include ceramic particles and garnet-type modified LLZO solid electrolytes. The two sides of the diaphragm have different bonding properties, so that the diaphragm can ensure that the diaphragm has proper bonding property to the anode and the cathode respectively, the problem that the anode is difficult to infiltrate due to firm bonding is solved, and the cathode can be prevented from falling off in a layering way due to weaker bonding; in addition, the problem of bending deformation of the first unit in the preparation process can be avoided, and the yield is improved.
Description
Technical Field
The invention relates to the field of lithium batteries, in particular to a double-sided differential lithium battery diaphragm and a lithium battery containing the diaphragm.
Background
In the existing lithium battery manufacturing process, a separator, a positive electrode and a negative electrode are connected and fixed by hot pressing. At this time, if the diaphragm with the coating capable of realizing the bonding function is adopted, the two sides of the diaphragm can respectively bond the positive electrode and the negative electrode. The method can effectively avoid deformation dislocation of the diaphragm, the anode and the cathode in the process of manufacturing, transferring and applying the battery cell, and improve the quality of the battery cell; and meanwhile, the interface between the diaphragm and the positive electrode and the interface between the diaphragm and the negative electrode are improved, and the performance of the battery cell is improved (such as reducing the internal resistance of the battery cell, improving the circulation of the battery cell and the like).
However, the positive electrode and the negative electrode manufactured by actual production often have bending to a certain extent, after the positive electrode and the negative electrode are fixed by using the adhesive diaphragm, the first unit formed by the positive electrode, the negative electrode and the diaphragm often has internal stress due to different bending deformation directions and sizes, so that the first unit is uneven, and the uneven surface can influence the alignment degree of subsequent lamination and the flatness of a final battery cell, and finally influence the manufacturing yield.
On the other hand, the two sides of the existing diaphragm adopt adhesive coatings with the same type and the same coating amount, and the diaphragm can show different adhesive force to the positive electrode and the negative electrode due to the difference of the surface morphology and the surface energy of the positive electrode and the negative electrode, so that the adhesive force to the positive electrode is often too large, the electrolyte is relatively difficult to infiltrate into the positive electrode, and the capacity exertion and the cycle performance of the battery are finally influenced; and because the polarity of the negative electrode is usually weaker, the roughness is lower, the bonding force formed by the negative electrode and the diaphragm is weaker, and the negative electrode and the diaphragm are easy to fall off in a layering manner when enough bonding force cannot be ensured in the hot pressing process, so that the manufacturing process of the battery cell and the yield of the final battery cell are affected.
Disclosure of Invention
The invention provides a double-sided differential lithium battery diaphragm and a lithium battery containing the same, and aims at solving the problems that the existing diaphragm can form different and extremely different cohesive forces to positive and negative electrodes when the diaphragm has the same coating amount and the same cohesive layer, and the negative electrode is not firmly bonded due to the cohesive force, and a first unit formed after the cohesive force is bent and deformed. According to the invention, different bonding properties of the two sides of the diaphragm are realized by controlling the surface density and the coating composition of the coatings on the two sides of the diaphragm, so that the reasonable bonding property of the diaphragm to the anode and the cathode is ensured, the problem that the anode is hard to infiltrate due to firm bonding is solved, and the problem that the cathode is easy to fall off due to layering in the production and use process due to weak bonding of the cathode can be avoided; in addition, by designing different bonding forces for the positive electrode and the negative electrode, the matching of the bending deformation degree of the positive electrode plate and the negative electrode plate can be realized, the problem of the bending deformation of the first unit which is easy to occur when the diaphragm is used for bonding the positive electrode and the negative electrode can be better overcome, the manufacturing yield is improved, and the performance of the battery cell is prevented from being reduced.
The specific technical scheme of the invention is as follows:
in a first aspect, the present invention provides a double-sided differential lithium battery separator comprising a polymer-based film; the two sides of the polymer base film are respectively coated with an anode attaching coating and a cathode attaching coating; the positive electrode attaching coating and the negative electrode attaching coating both comprise polymer adhesive and inorganic material particles, and the adhesive force of the positive electrode attaching coating is smaller than that of the negative electrode attaching coating; the inorganic material particles include ceramic particles and garnet-type modified LLZO solid electrolytes.
The two sides of the existing diaphragm often adopt the same bonding layer, but the adopted coating is more to the positive electrode to realize stronger bonding, the bonding to the negative electrode is weaker, delamination and negative electrode falling caused by weaker bonding to the negative electrode are easy to occur in the using process, the problem can cause production yield reduction on one hand, and the interface between the diaphragm and the negative electrode is not beneficial to improvement on the other hand, so that the battery performance is influenced. Therefore, the invention specifically designs the adhesive coating on the two sides of the diaphragm according to the surface morphology and the surface energy difference of the positive electrode and the negative electrode, and the adhesive force of the positive electrode adhesive coating is smaller than that of the negative electrode adhesive coating. The design can ensure that the diaphragm has proper adhesion to the positive electrode and the negative electrode respectively. The advantages are that: (1) the deformation and bending degree of the anode and the cathode can be better matched, the problem that the bending deformation of the first unit is obvious due to the fact that the anode and the cathode are bonded together is solved, the manufacturing yield is improved, and meanwhile the problem that the performance of the battery cell is reduced due to the deformation of the battery cell is solved. (2) Solves the problem that the positive electrode is difficult to infiltrate due to over-firm adhesion, and can avoid the delamination and falling of the negative electrode easily occurring in the production and use process due to weaker negative electrode adhesion.
In addition, the inorganic material particles are added in the positive/negative electrode attaching coating, so that the mechanical property of the separator can be ensured. And the inorganic material particles also contain garnet-type modified LLZO solid electrolyte. Compared with the liquid electrolyte, the solid electrolyte has good conductivity, good thermal stability and chemical stability, so that the garnet-type modified LLZO solid electrolyte with low resistivity is doped in the inorganic material particles of the anode/cathode adhesive coating, the electric contact between the anode and the cathode and the diaphragm can be further improved, and the interface impedance is reduced.
Preferably, the surface density of the positive electrode attaching coating is 0.2-0.8g/m 2 The surface density of the negative electrode attaching coating is 0.3-2.5g/m 2 The method comprises the steps of carrying out a first treatment on the surface of the And the surface density of the positive electrode attaching coating is smaller than that of the negative electrode attaching coating.
Preferably, the garnet-type modified LLZO solid electrolyte has a smaller ratio in the inorganic material particles of the positive electrode tab coating than in the inorganic material particles of the negative electrode tab coating.
When the negative electrode material of the lithium battery is a silicon-containing material, the silicon material is easy to expand after multiple cycles, so that the silicon material is separated from the diaphragm and gaps are generated, poor electrical contact between the negative electrode and the diaphragm can be caused, and the garnet-type modified LLZO solid electrolyte with higher content is required to be doped in the negative electrode attaching coating to compensate conductivity.
Preferably, the garnet-type modified LLZO solid electrolyte accounts for 15-25wt% of the inorganic material particles of the positive electrode adhesion coating; the garnet-type modified LLZO solid electrolyte accounts for 25-35wt% of the inorganic material particles of the negative electrode adhesion coating.
Preferably, the preparation method of the garnet-type modified LLZO solid electrolyte comprises the following steps:
a) Batching according to the element composition in LLZO, and adding raw materials containing Ga and Al on the basis of the batching; all the raw materials are added into a three-dimensional high-energy vibration ball mill for ball milling, sintered in air at 300-400 ℃, cooled, continuously ball milled, and then subjected to anaerobic sintering at 300-500Mpa and 900-1100 ℃ to prepare the Al/Ga doped modified LLZO solid electrolyte.
B) Mixing polypropylene carbonate and acetone uniformly, adding lithium perchlorate for full dissolution, adding Al/Ga doped modified LLZO solid electrolyte into the obtained mixed solution, continuing ultrasonic mixing uniformly, and sintering at a low temperature of 300-400Mpa and 100-250 ℃ to obtain garnet type modified LLZO solid electrolyte.
Since the solid electrolyte is granular, the contact area between the common LLZO and the electrode plate which is solid is limited, and the impedance is larger. In order to reduce the solid-solid interface impedance between the solid electrolyte and the electrode, the invention modifies LLZO:
in the step A), the invention improves the mixing efficiency of raw materials by a three-dimensional high-energy vibration ball milling method, and prepares the Al/Ga doped modified LLZO solid electrolyte by high-temperature sintering. Specifically, after the first air sintering at 300-400 ℃, the interfacial compatibility between different raw materials can be promoted, in the temperature range, the interfacial compatibility between different raw materials can be accelerated, meanwhile, the oxygen reaction activity is low, the reaction between the raw materials and each element in the materials is difficult, the raw materials can be carried out in the air, the production cost is reduced, the second high-pressure high-temperature (300-500 mpa,900-1100 ℃) anaerobic sintering is facilitated, in the temperature range, the crystallinity and the compactness of the product are improved, and because the oxygen reaction activity is high, unnecessary side reactions can occur with the raw materials, so that the product contains impurities, and the step is carried out under the anaerobic condition.
In step B), in order to reduce the resistance of the LLZO solid electrolyte, the present invention adopts a low-temperature cold sintering technique to modify the interface of the Al/Ga doped modified LLZO solid electrolyte to reduce the interface resistance. Specifically, the team of the invention finds that LLZO solid electrolyte is very sensitive to moisture, and a lithium carbonate layer is easy to generate on the surface of the material after the LLZO solid electrolyte is contacted with water, so that the lithium ion transmission resistance is increased. Therefore, on one hand, the invention adopts the non-aqueous solvent of acetone and carbonic acid polypropylene to carry out surface coating on the solid electrolyte, so as to avoid the contact between the solid electrolyte and the aqueous solvent; on the other hand, a small amount of lithium perchlorate can form a salt bridge on the surface of the LLZO material, and the crystal boundary on the surface of the LLZO can be easily repaired in a non-aqueous solvent environment and at low temperature, so that the LLZO solid electrolyte with low interface resistance is obtained.
Preferably, in step a), the total doping amount of Ga and Al in LLZO is not more than 5wt%.
Preferably, in step A), the starting materials are Li respectively 2 CO 3 、La 2 O 3 、ZrO 2 、Ga 2 O 3 And Al 2 O 3 。
Preferably, in step A), the Li 2 CO 3 The balance of 5-15wt% is additionally added.
Preferably, in the step a), the inner wall of the three-dimensional high-energy vibration ball mill is made of zirconia, the grinding balls are steel balls, tungsten carbide balls or polyamine peptide balls, and the ball milling conditions are as follows: ball-milling for 5-10 min at normal temperature with the ball-material ratio of 20-50:40-80; after cooling, the ball milling is continued for 10-20 minutes.
The particle size of the LLZO solid electrolyte is mainly controlled by ball milling time and ball material ratio, and the longer the ball milling time is, the higher the ball material ratio is, and the smaller the particle size of the material is.
Preferably, in step A), sintering is carried out in air at 300-400 ℃ for 1-3 hours, then cooling to room temperature at a speed of 10-20 ℃/min, continuing ball milling mixing, and sintering at 900-1100 ℃ for 6-12 hours under 300-500 Mpa.
Preferably, in step A), the obtained Al/Ga doped modified LLZO solid electrolyte has an average particle diameter of 0.2-1.0 μm.
Preferably, in the step B), the carbonic acid polypropylene and the acetone are ultrasonically mixed for 5-15 minutes according to the volume ratio of 1-3:2-5 at normal temperature, and lithium perchlorate is added until the lithium perchlorate is completely dissolved, wherein the concentration of the lithium perchlorate is 35-55wt%.
Preferably, in the step B), the mass ratio of the mixed solution to the Al/Ga doped modified LLZO solid electrolyte is (2-8) to (65-80).
Preferably, in the step B), after the Al/Ga doped modified LLZO solid electrolyte is added, ultrasonic mixing is continued for 20-40 minutes, and sintering is carried out at a low temperature for 1-3 hours.
Preferably, the polymer binder in the positive electrode attachment coating is one or more of PVDF, PC, PMMA and PAN.
Preferably, the polymer binder in the negative electrode attachment coating layer is one or more of PAA, PVA, EVOH and SBR.
Preferably, the ceramic particles are at least one of alumina, boehmite, barium sulfate, magnesium sulfate, and silicon oxide.
Preferably, the polymer base film is one of a PE single-layer diaphragm, a PP single-layer diaphragm, and a PE and PP composite multi-layer diaphragm.
In a second aspect, the invention provides a lithium battery comprising the double-sided differential lithium battery separator.
Preferably, the hot pressing method of the lithium battery in the preparation process comprises the following steps:
1) Primary hot pressing: after the cell is packaged and injected with liquid, the cell is subjected to primary hot pressing at 50-100 ℃ and 0.1-3 MPa;
2) And (3) secondary hot pressing: performing secondary hot pressing on the battery core at the temperature of 0-40 ℃ and under the pressure of 0.1-3 MPa;
3) Standing: standing the battery cell after the secondary hot pressing;
4) Degassing: the cells were degassed under vacuum.
The HF generated by side reaction and moisture in the battery core can be thoroughly vaporized by adopting higher temperature in one hot pressing, and can be removed in the subsequent degassing process, so that the occurrence of the side reaction in the later stage of the battery can be reduced, and the expansion caused by the gas production of the battery can be restrained. After secondary hot pressing and standing, the diaphragm can be tightly attached to the positive pole piece and the negative pole piece, so that the thickness expansion of the negative pole piece is effectively reduced, poor contact between the pole piece and the diaphragm caused by repeated thickness change in the continuous charging and discharging process during battery circulation is prevented, increase of the internal gap of the battery is inhibited, and good capacity retention rate is ensured.
Preferably, the primary hot pressing is performed before the cell is pre-charged, after the cell is formed or after the cell is divided into capacity, and the electric quantity of the cell is 0-100% SOC.
Preferably, in step 1), the time of one hot pressing is 5 to 15 minutes.
Preferably, in step 2), the time of the secondary hot pressing is 5 to 45 minutes.
Preferably, in step 3), the standing time is 0.1 to 24 hours and the temperature is 0 to 40 ℃.
Preferably, in step 4), the vacuum degree of the degassing is-80 to-99 kPa.
Compared with the prior art, the invention has the beneficial effects that:
(1) The invention realizes different bonding performance of the two sides of the diaphragm by controlling the surface density and the coating composition of the coatings on the two sides of the diaphragm, thereby ensuring that the diaphragm has proper bonding property to the anode and the cathode respectively, solving the problem that the anode is hard to infiltrate due to over-firm bonding, and simultaneously avoiding the delamination and falling of the cathode which are easy to occur in the production and use process due to weaker bonding of the cathode.
(2) According to the invention, different bonding forces are designed for the positive electrode and the negative electrode through the diaphragm, so that the matching of bending deformation degrees of the positive electrode plate and the negative electrode plate can be realized, the problem of bending deformation of the first unit which is easy to occur when the diaphragm is used for bonding the positive electrode and the negative electrode can be better overcome, the manufacturing yield is improved, and the performance of the battery cell is prevented from being reduced.
(3) According to the invention, a proper amount of garnet-type modified LLZO solid electrolyte with low resistivity is doped in the inorganic material particles of the positive/negative electrode attaching layer of the diaphragm, so that the electric contact between the positive and negative electrodes and the diaphragm can be further improved, and the interface impedance is reduced.
(4) According to the invention, a specific twice hot-pressing process and a cell degassing process are adopted, on one hand, the twice hot-pressing process provides continuous and stable cohesive force between the positive electrode plate and the diaphragm, so that the thickness expansion of the negative electrode plate can be effectively reduced, poor contact between the electrode plate and the diaphragm caused by repeated thickness change in the continuous charging and discharging process when the battery is circulated is prevented, the increase of the internal gap of the battery is inhibited, and the good capacity retention rate is ensured. On the other hand, HF generated by side reaction and moisture in the power core is consumed at a higher temperature in the primary hot pressing process, so that the occurrence of the side reaction in the later stage of the battery is reduced, and the expansion caused by gas production of the battery is restrained.
Detailed Description
The invention is further described below with reference to examples.
General examples
A double-sided differential lithium battery diaphragm comprises a polymer base film (PE single-layer diaphragm, PP single-layer diaphragm, PE and PP composite multi-layer diaphragm)) The method comprises the steps of carrying out a first treatment on the surface of the The two sides of the polymer base film are respectively coated with an anode attaching coating and a cathode attaching coating; the adhesive force of the positive electrode adhesive coating is smaller than that of the negative electrode adhesive coating; the specific characteristics are that the surface density and the composition of the positive electrode and the negative electrode attached coating are different. The surface density of the positive electrode attaching coating is smaller than that of the negative electrode attaching coating; the surface density of the positive electrode attaching coating is 0.2-0.8g/m 2 The surface density of the negative electrode attaching coating is 0.3-2.5g/m 2 。
The positive electrode adhesion coating and the negative electrode adhesion coating each include a polymer binder and inorganic material particles. The polymer binder in the positive electrode attachment coating is one or more of PVDF, PC, PMMA and PAN; the polymer binder in the negative electrode attachment coating is one or more of PAA, PVA, EVOH and SBR. The inorganic material particles include ceramic particles and garnet-type modified LLZO solid electrolytes. The ceramic particles are at least one of aluminum oxide, boehmite, barium sulfate, magnesium sulfate and silicon oxide. The garnet-type modified LLZO solid electrolyte has a smaller ratio in the inorganic material particles of the positive electrode tab coating than in the inorganic material particles of the negative electrode tab coating. Preferably, the garnet-type modified LLZO solid electrolyte has a proportion of 15 to 25wt% in the inorganic material particles of the positive electrode tab coating layer and a proportion of 25 to 35wt% in the inorganic material particles of the negative electrode tab coating layer.
The preparation method of the garnet-type modified LLZO solid electrolyte comprises the following steps:
a) The method comprises the following steps By Li 2 CO 3 (purity 99.9%, addition of 5-15% excess Li) 2 CO 3 To compensate for Li loss during sintering), la 2 O 3 (purity 99.9%), zrO 2 (purity 99.9%) Ga 2 O 3 (purity 99.9%) Al 2 O 3 (purity 99.9%) is used as raw material, and is added into a three-dimensional high-energy vibration ball mill (the total doping amount of Ga and Al in LLZO is not more than 5 wt%) according to the required stoichiometric ratio, the inner wall of the ball mill is made of zirconia, the grinding ball is one of steel ball, tungsten carbide ball and polyamine peptide ball, the ball-material ratio is 20-50:40-80, ball milling is carried out for 5-10 min at normal temperature, sintering is carried out in air at 300-400 ℃ for 1-3 h, and the interface between different raw materials is promotedCooling to room temperature at the speed of 10-20 ℃/min, continuously ball milling and mixing for 10-20 min, performing anaerobic sintering at the temperature of 900-1100 ℃ for 6-12 h under 300-500Mpa, and increasing the crystallinity and density to obtain the Al/Ga doped modified LLZO solid electrolyte with the average particle size of 0.2-1.0 mu m.
B) Firstly, adding lithium perchlorate (LiClO) into polypropylene carbonate and acetone at normal temperature according to the volume ratio of 1-3:2-5 for ultrasound for 5-15 minutes 4 ) Ultrasonic to lithium perchlorate total dissolution (LiClO 4 Mass fraction 35-55%); adding Al/Ga doped modified LLZO solid electrolyte (the mass ratio of the mixed solution to the Al/Ga doped modified LLZO solid electrolyte is 2-8:65-80) into the mixed solution, continuously ultrasonically mixing for 20-40 minutes, and then sintering at 300-400mpa and 100-250 ℃ for 1-3 hours to obtain the garnet type modified LLZO solid electrolyte.
A lithium battery containing double-sided differential lithium battery separator, the hot pressing method in the preparation process of the lithium battery comprises the following steps:
1) Primary hot pressing: after the cell is packaged and injected with liquid, the cell is subjected to primary hot pressing for 5 to 15 minutes at the temperature of 50 to 100 ℃ and under the pressure of 0.1 to 3 MPa;
2) And (3) secondary hot pressing: performing secondary hot pressing on the battery cell for 5-45 min at the temperature of 0-40 ℃ and under the pressure of 0.1-3 MPa;
3) Standing: standing the battery cell (0-40 ℃ for 0.1-24 h) after the secondary hot pressing;
4) Degassing: the cells were degassed under vacuum (-80 to-99 kP).
Example 1
A double-sided differential lithium battery diaphragm comprises a polymer base film (PE single-layer diaphragm, thickness is 9 μm), and two sides of the polymer base film are respectively coated with a positive electrode attaching coating (thickness is 2 μm) and a negative electrode attaching coating (thickness is 2.5 μm); the surface density of the positive electrode attaching coating is 0.4g/m 2 The surface density of the negative electrode attaching coating is 0.8g/m 2 。
The mass ratio of the polymer binder PMMA to the inorganic material particles (70% of alumina and 30% of garnet-type modified LLZO solid electrolyte) in the positive electrode attaching coating is 1:1; the mass ratio of the polymer binder PAA and the inorganic material particles (80% of alumina, 20% of garnet-modified LLZO solid electrolyte) in the negative electrode active coating was 1:1.
The preparation method of the garnet-type modified LLZO solid electrolyte comprises the following steps:
preparation of Al/Ga doped modified LLZO solid electrolyte: by Li 2 CO 3 (purity 99.9%, adding 10% excess Li) 2 CO 3 To compensate for Li loss during sintering), la 2 O 3 (purity 99.9%), zrO 2 (purity 99.9%) Ga 2 O 3 (purity 99.9%) Al 2 O 3 (purity 99.9%) is used as a raw material, the raw material is added into a three-dimensional high-energy vibration ball mill according to a required stoichiometric ratio (1% of Ga and 1% of Al doping), zirconia materials on the inner wall of the ball mill are ground into tungsten carbide balls, the ball material ratio is 25:45, ball milling is carried out for 10 minutes at normal temperature, sintering is carried out in air at 400 ℃ for 3 hours, interfacial compatibility between different raw materials is promoted, the raw material is cooled to room temperature according to a speed of 10 ℃/minute, ball milling and mixing are continued for 10 minutes, anaerobic sintering is carried out at 1000 ℃ for 8 hours at 400Mpa, crystallinity and compactness are increased, and the Al/Ga doping modified LLZO solid electrolyte is prepared, wherein the average particle size is 0.5-1.0 mu m.
And (3) low-temperature cold sintering modification: firstly, the polypropylene carbonate and the acetone are ultrasonically treated for 10 minutes according to the volume ratio of 1.5:3 at normal temperature, and lithium perchlorate (LiClO) is added 4 ) Ultrasonic to lithium perchlorate total dissolution (LiClO 4 45% by mass); adding an Al/Ga doped modified LLZO solid electrolyte (the mass ratio of the mixed solution to the Al/Ga doped modified LLZO solid electrolyte is 5:70) into the mixed solution, continuously carrying out ultrasonic mixing for 40 minutes, and then carrying out low-temperature sintering at 400mpa and 100 ℃ for 2.5 hours to obtain the LLZO solid electrolyte.
A lithium battery containing the double-sided differential lithium battery diaphragm uses a cell system of an NMC811 positive electrode and a silicon-carbon negative electrode. The assembly process of the battery is as follows: uniformly dispersing an anode active material NCM811, a conductive agent carbon black and an anode binder polyvinylidene fluoride in NMP (N-methyl pyrrolidone) according to the weight ratio of 96:1.5:2.5 to prepare slurry, coating the slurry on two sides of an aluminum foil, respectively leaving 14mm empty foils at two ends of the aluminum foil, drying, rolling for standby, and punching after half-cutting to obtain an anode plate. Uniformly dispersing a silicon-carbon material serving as a cathode active material, carbon black serving as a conductive agent, SBR serving as a binder and sodium carboxymethylcellulose in deionized water according to the weight ratio of 94:2:2.5:1.5 to prepare slurry, coating the slurry on two sides of a copper foil, respectively leaving 16mm empty foils at two ends of the copper foil, drying, rolling for standby, and punching after half-cutting to obtain a cathode pole piece. And the prepared diaphragm and the positive and negative electrode plates are connected with each other through dry pressing according to the sequence of positive electrode, diaphragm, negative electrode, diaphragm and positive electrode to form a first unit, and then are connected with each other through dry pressing according to the sequence of diaphragm, negative electrode and diaphragm to form a second unit. And stacking the first unit and the second unit in sequence to obtain the battery cell structure. The dry pressure temperature is 70 ℃ and the pressure is 1Mpa.
After the battery cell is encapsulated and injected with liquid (electrolyte), hot pressing is carried out:
1) Primary hot pressing: after the cell is packaged and injected with liquid, the cell is subjected to primary hot pressing for 10min at 75 ℃ and 0.2 MPa;
2) And (3) secondary hot pressing: performing secondary hot pressing on the battery cell at 20 ℃ and 0.2MPa for 25min;
3) Standing: standing the battery cell (20 ℃ for 12 h) after the secondary hot pressing;
4) Degassing: the cells were degassed under vacuum (-90 kP).
Example 2
A double-sided differential lithium battery diaphragm comprises a polymer base film (PE single-layer diaphragm, thickness is 9 μm), and two sides of the polymer base film are respectively coated with a positive electrode attaching coating (thickness is 2 μm) and a negative electrode attaching coating (thickness is 2.5 μm); the surface density of the positive electrode attaching coating is 0.4g/m 2 The surface density of the negative electrode attaching coating is 0.6g/m 2 。
The mass ratio of the polymer binder PVDF and the inorganic material particles (70% of boehmite and 30% of garnet-type modified LLZO solid electrolyte) in the positive electrode adhesive coating is 1:1; the mass ratio of the polymer binder PVA to the inorganic material particles (80% boehmite, 20% garnet-type modified LLZO solid electrolyte) in the negative electrode active coating was 1:1.
The preparation method of the garnet-type modified LLZO solid electrolyte comprises the following steps:
Al/Ga doping modificationPreparation of LLZO solid electrolyte: by Li 2 CO 3 (purity 99.9%, adding 10% excess Li) 2 CO 3 To compensate for Li loss during sintering), la 2 O 3 (purity 99.9%), zrO 2 (purity 99.9%) Ga 2 O 3 (purity 99.9%) Al 2 O 3 (purity 99.9%) is used as a raw material, the raw material is added into a three-dimensional high-energy vibration ball mill according to a required stoichiometric ratio (1% of Ga and 1% of Al doping), zirconia materials on the inner wall of the ball mill are ground into tungsten carbide balls, the ball material ratio is 25:45, ball milling is carried out for 10 minutes at normal temperature, sintering is carried out in air at 400 ℃ for 3 hours, interfacial compatibility between different raw materials is promoted, the raw material is cooled to room temperature according to a speed of 10 ℃/minute, ball milling and mixing are continued for 10 minutes, anaerobic sintering is carried out at 1000 ℃ for 8 hours at 400Mpa, crystallinity and compactness are increased, and the Al/Ga doping modified LLZO solid electrolyte is prepared, wherein the average particle size is 0.5-1.0 mu m.
And (3) low-temperature cold sintering modification: firstly, the polypropylene carbonate and the acetone are ultrasonically treated for 10 minutes according to the volume ratio of 1.5:3 at normal temperature, and lithium perchlorate (LiClO) is added 4 ) Ultrasonic to lithium perchlorate total dissolution (LiClO 4 45% by mass); adding an Al/Ga doped modified LLZO solid electrolyte (the mass ratio of the mixed solution to the Al/Ga doped modified LLZO solid electrolyte is 5:70) into the mixed solution, continuously carrying out ultrasonic mixing for 40 minutes, and then carrying out low-temperature sintering at 400mpa and 100 ℃ for 2.5 hours to obtain the LLZO solid electrolyte.
A lithium battery containing the double-sided differential lithium battery diaphragm uses a cell system of an NMC811 positive electrode and a silicon-carbon negative electrode. The assembly process of the battery is as follows: uniformly dispersing an anode active material NCM811, a conductive agent carbon black and an anode binder polyvinylidene fluoride in NMP (N-methyl pyrrolidone) according to the weight ratio of 96:1.5:2.5 to prepare slurry, coating the slurry on two sides of an aluminum foil, respectively leaving 14mm empty foils at two ends of the aluminum foil, drying, rolling for standby, and punching after half-cutting to obtain an anode plate. Uniformly dispersing a silicon-carbon material serving as a cathode active material, carbon black serving as a conductive agent, SBR serving as a binder and sodium carboxymethylcellulose in deionized water according to the weight ratio of 94:2:2.5:1.5 to prepare slurry, coating the slurry on two sides of a copper foil, respectively leaving 16mm empty foils at two ends of the copper foil, drying, rolling for standby, and punching after half-cutting to obtain a cathode pole piece. And the prepared diaphragm and the positive and negative electrode plates are connected with each other through dry pressing according to the sequence of positive electrode, diaphragm, negative electrode, diaphragm and positive electrode to form a first unit, and then are connected with each other through dry pressing according to the sequence of diaphragm, negative electrode and diaphragm to form a second unit. And stacking the first unit and the second unit in sequence to obtain the battery cell structure. The dry pressure temperature is 70 ℃ and the pressure is 1Mpa.
After the battery cell is encapsulated and injected with liquid (electrolyte), hot pressing is carried out:
1) Primary hot pressing: after the cell is packaged and injected with liquid, the cell is subjected to primary hot pressing for 10min at 75 ℃ and 0.2 MPa;
2) And (3) secondary hot pressing: performing secondary hot pressing on the battery cell at 20 ℃ and 0.2MPa for 25min;
3) Standing: standing the battery cell (20 ℃ for 12 h) after the secondary hot pressing;
4) Degassing: the cells were degassed under vacuum (-90 kP).
Example 3
A double-sided differential lithium battery diaphragm comprises a polymer base film (PE single-layer diaphragm, thickness is 9 μm), and two sides of the polymer base film are respectively coated with a positive electrode attaching coating (thickness is 1.5 μm) and a negative electrode attaching coating (thickness is 2.0 μm); the surface density of the positive electrode attaching coating is 0.6g/m 2 The surface density of the negative electrode attaching coating is 1.4g/m 2 。
The mass ratio of the polymer binder PMMA to the inorganic material particles (magnesium sulfate 70% and garnet-type modified LLZO solid electrolyte 30%) in the positive electrode attaching coating is 1:1; the mass ratio of the polymer binder PAA and the inorganic material particles (magnesium sulfate 80%, garnet-modified LLZO solid electrolyte 20%) in the negative electrode active coating was 1:1.
The preparation method of the garnet-type modified LLZO solid electrolyte comprises the following steps:
preparation of Al/Ga doped modified LLZO solid electrolyte: by Li 2 CO 3 (purity 99.9%, adding 10% excess Li) 2 CO 3 To compensate for Li loss during sintering), la 2 O 3 (purity 99.9%), zrO 2 (purity 99.9%))，Ga 2 O 3 (purity 99.9%) Al 2 O 3 (purity 99.9%) is used as a raw material, the raw material is added into a three-dimensional high-energy vibration ball mill according to a required stoichiometric ratio (1% of Ga and 1% of Al doping), zirconia materials on the inner wall of the ball mill are ground into tungsten carbide balls, the ball material ratio is 25:45, ball milling is carried out for 10 minutes at normal temperature, sintering is carried out in air at 400 ℃ for 3 hours, interfacial compatibility between different raw materials is promoted, the raw material is cooled to room temperature according to a speed of 10 ℃/minute, ball milling and mixing are continued for 10 minutes, anaerobic sintering is carried out at 1000 ℃ for 8 hours at 400Mpa, crystallinity and compactness are increased, and the Al/Ga doping modified LLZO solid electrolyte is prepared, wherein the average particle size is 0.5-1.0 mu m.
And (3) low-temperature cold sintering modification: firstly, the polypropylene carbonate and the acetone are ultrasonically treated for 10 minutes according to the volume ratio of 1.5:3 at normal temperature, and lithium perchlorate (LiClO) is added 4 ) Ultrasonic to lithium perchlorate total dissolution (LiClO 4 45% by mass); adding an Al/Ga doped modified LLZO solid electrolyte (the mass ratio of the mixed solution to the Al/Ga doped modified LLZO solid electrolyte is 5:70) into the mixed solution, continuously carrying out ultrasonic mixing for 40 minutes, and then carrying out low-temperature sintering at 400mpa and 100 ℃ for 2.5 hours to obtain the LLZO solid electrolyte.
A lithium battery containing the double-sided differential lithium battery diaphragm uses a cell system of an NMC811 positive electrode and a silicon-carbon negative electrode. The assembly process of the battery is as follows: uniformly dispersing an anode active material NCM811, a conductive agent carbon black and an anode binder polyvinylidene fluoride in NMP (N-methyl pyrrolidone) according to the weight ratio of 96:1.5:2.5 to prepare slurry, coating the slurry on two sides of an aluminum foil, respectively leaving 14mm empty foils at two ends of the aluminum foil, drying, rolling for standby, and punching after half-cutting to obtain an anode plate. Uniformly dispersing a silicon-carbon material serving as a cathode active material, carbon black serving as a conductive agent, SBR serving as a binder and sodium carboxymethylcellulose in deionized water according to the weight ratio of 94:2:2.5:1.5 to prepare slurry, coating the slurry on two sides of a copper foil, respectively leaving 16mm empty foils at two ends of the copper foil, drying, rolling for standby, and punching after half-cutting to obtain a cathode pole piece. And the prepared diaphragm and the positive and negative electrode plates are connected with each other through dry pressing according to the sequence of positive electrode, diaphragm, negative electrode, diaphragm and positive electrode to form a first unit, and then are connected with each other through dry pressing according to the sequence of diaphragm, negative electrode and diaphragm to form a second unit. And stacking the first unit and the second unit in sequence to obtain the battery cell structure. The dry pressure temperature is 70 ℃ and the pressure is 1Mpa.
After the battery cell is encapsulated and injected with liquid (electrolyte), hot pressing is carried out:
1) Primary hot pressing: after the cell is packaged and injected with liquid, the cell is subjected to primary hot pressing for 10min at 75 ℃ and 0.2 MPa;
2) And (3) secondary hot pressing: performing secondary hot pressing on the battery cell at 20 ℃ and 0.2MPa for 25min;
3) Standing: standing the battery cell (20 ℃ for 12 h) after the secondary hot pressing;
4) Degassing: the cells were degassed under vacuum (-90 kP).
Example 4
A double-sided differential lithium battery diaphragm comprises a polymer base film (PE diaphragm, thickness is 9 μm), and the two sides of the polymer base film are respectively coated with a positive electrode attaching coating (thickness is 2.5 μm) and a negative electrode attaching coating (thickness is 3.0 μm); the surface density of the positive electrode attaching coating is 0.5g/m 2 The surface density of the negative electrode attaching coating is 1.2g/m 2 。
The mass ratio of the polymer binder PMMA to the inorganic material particles (silicon oxide 70% and garnet-type modified LLZO solid electrolyte 30%) in the positive electrode attaching coating is 1:1; the mass ratio of the polymer binder PAA and the inorganic material particles (silica 80%, garnet-modified LLZO solid electrolyte 20%) in the negative electrode active coating was 1:1.
The preparation method of the garnet-type modified LLZO solid electrolyte comprises the following steps:
preparation of Al/Ga doped modified LLZO solid electrolyte: by Li 2 CO 3 (purity 99.9%, adding 10% excess Li) 2 CO 3 To compensate for Li loss during sintering), la 2 O 3 (purity 99.9%), zrO 2 (purity 99.9%) Ga 2 O 3 (purity 99.9%) Al 2 O 3 (purity 99.9%) is used as raw material, and is added into a three-dimensional high-energy vibration ball mill according to the required stoichiometric ratio (1% Ga and 1% Al doping), the inner wall of the ball mill is made of zirconia material, and the grinding balls areThe tungsten carbide ball is ball-milled for 10 minutes at normal temperature according to the ball-material ratio of 25:45, sintered for 3 hours in air at 400 ℃, so as to promote the interfacial compatibility between different raw materials, cooled to room temperature according to the speed of 10 ℃/minute, continuously ball-milled and mixed for 10 minutes, and subjected to anaerobic sintering at 1000 ℃ for 8 hours under 400Mpa, and the crystallinity and the density are increased, so that the Al/Ga doped modified LLZO solid electrolyte with the average particle size of 0.5-1.0 mu m is prepared.
And (3) low-temperature cold sintering modification: firstly, the polypropylene carbonate and the acetone are ultrasonically treated for 10 minutes according to the volume ratio of 1.5:3 at normal temperature, and lithium perchlorate (LiClO) is added 4 ) Ultrasonic to lithium perchlorate total dissolution (LiClO 4 45% by mass); adding an Al/Ga doped modified LLZO solid electrolyte (the mass ratio of the mixed solution to the Al/Ga doped modified LLZO solid electrolyte is 5:70) into the mixed solution, continuously carrying out ultrasonic mixing for 40 minutes, and then carrying out low-temperature sintering at 400mpa and 100 ℃ for 2.5 hours to obtain the LLZO solid electrolyte.
A lithium battery containing the double-sided differential lithium battery diaphragm uses a cell system of an NMC811 positive electrode and a silicon-carbon negative electrode. The assembly process of the battery is as follows: uniformly dispersing an anode active material NCM811, a conductive agent carbon black and an anode binder polyvinylidene fluoride in NMP (N-methyl pyrrolidone) according to the weight ratio of 96:1.5:2.5 to prepare slurry, coating the slurry on two sides of an aluminum foil, respectively leaving 14mm empty foils at two ends of the aluminum foil, drying, rolling for standby, and punching after half-cutting to obtain an anode plate. Uniformly dispersing a silicon-carbon material serving as a cathode active material, carbon black serving as a conductive agent, SBR serving as a binder and sodium carboxymethylcellulose in deionized water according to the weight ratio of 94:2:2.5:1.5 to prepare slurry, coating the slurry on two sides of a copper foil, respectively leaving 16mm empty foils at two ends of the copper foil, drying, rolling for standby, and punching after half-cutting to obtain a cathode pole piece. And the prepared diaphragm and the positive and negative electrode plates are connected with each other through dry pressing according to the sequence of positive electrode, diaphragm, negative electrode, diaphragm and positive electrode to form a first unit, and then are connected with each other through dry pressing according to the sequence of diaphragm, negative electrode and diaphragm to form a second unit. And stacking the first unit and the second unit in sequence to obtain the battery cell structure. The dry pressure temperature is 70 ℃ and the pressure is 1Mpa.
After the battery cell is encapsulated and injected with liquid (electrolyte), hot pressing is carried out:
1) Primary hot pressing: after the cell is packaged and injected with liquid, the cell is subjected to primary hot pressing for 10min at 75 ℃ and 0.2 MPa;
2) And (3) secondary hot pressing: performing secondary hot pressing on the battery cell at 20 ℃ and 0.2MPa for 25min;
3) Standing: standing the battery cell (20 ℃ for 12 h) after the secondary hot pressing;
4) Degassing: the cells were degassed under vacuum (-90 kP).
Comparative example 1
The difference from example 1 is that the surface density of the positive and negative electrode coating layers of the separator was 0.8g/m 2 。
Comparative example 2
The difference from example 1 is that the surface density of the positive and negative electrode coating layers of the separator was 0.3g/m 2 。
Comparative example 3
The difference from example 1 is that the inorganic material particles in the separator positive/negative electrode active material coating layer are pure alumina particles, and no garnet-type modified LLZO solid electrolyte is contained.
Comparative example 4
The difference from example 1 is that the solid electrolyte in the separator positive/negative electrode paste coating layer is an unmodified LLZO solid electrolyte.
Comparative example 5
Comparative example 5 differs from example 1 only in that: adopts a primary hot pressing process:
hot pressing: after the cell is packaged and injected with the liquid, the cell is hot-pressed for 25min at 20 ℃ and 0.2 MPa.
Standing: after the secondary hot pressing, the cell was allowed to stand at 20℃for 12 hours.
Degassing: the cells were degassed under vacuum (-90 kP).
Performance testing
The batteries obtained in examples 1 to 4 and comparative examples 1 to 5 were subjected to performance test in which the test magnification of capacity retention after 200 cycles was 0.5C, the voltage range was 2.7 to 4.2V, and the test temperature was 25C. The test results were as follows:
from the comparison of the above table data, it can be seen that:
the cell structures prepared in examples 1-4 show excellent performance, the first unit formed after the separator is bonded with the positive electrode and the negative electrode is not easy to bend and deform, the obtained cell state is flat, the cell capacity is slightly increased, and the cell capacity retention rate after 200 circles reaches more than 90% under the condition of normal temperature of 0.5 ℃. The separator with different bonding properties on two sides is prepared by changing the chemical composition of bonding layers on two sides of the separator and controlling the surface density of the bonding layers, so that the separator shows different bonding properties on the positive plate and the negative plate, and the dry pressing bonding force of the separator and the pole piece and the bending condition of the battery are improved. And the anode and cathode attached coating contains the modified LLZO solid electrolyte, so that the capacity retention rate can be further improved and the battery impedance can be reduced.
Comparative example 1 is a battery prepared from separators having the same positive and negative electrode-attached coating surface densities and compositions, and having high dry-press adhesion (the surface densities of the positive and negative electrode-attached coatings were both 0.8g/m 2 ) The battery cell manufacturing yield is good, but under the condition of guaranteeing the negative electrode binding force, the positive electrode binding force is too large, so that the electrolyte on the positive electrode side is relatively difficult to infiltrate and poor, the capacity exertion and the cycle performance of the battery are finally affected, and the capacity retention rate of the battery after 200 circles is only 78% under the condition of 0.5 ℃ at normal temperature.
Comparative example 2 is a battery prepared from separators having the same positive and negative electrode-attached coating surface densities and compositions, and having a low dry pressure adhesion (the positive and negative electrode-attached coatings each have a surface density of 0.3g/m 2 ) The separator has poor adhesion with the negative electrode in the preparation process and is easy to fall off, so that the manufacturing yield of the battery core is low and is only 90%, the capacity exertion and the cycle performance of the battery are simultaneously influenced, and the capacity retention rate of the battery after 200 circles is only 75% under the condition of 0.5 ℃ at normal temperature.
Comparative example 3 is different from example 1 in that the inorganic material particles in the separator, positive/negative electrode coating layer are pure alumina particles, and no garnet-type modified LLZO solid electrolyte is contained, so that the impedance between the positive and negative electrodes and the separator is large, and finally the capacity exertion and cycle performance of the battery are affected, and the capacity retention rate of the battery after 200 cycles is only 81% under the condition of normal temperature of 0.5C.
Comparative example 4 is different from example 1 in that the solid electrolyte in the separator positive/negative electrode tab coating layer is a normal LLZO solid electrolyte which has not been modified. The solid-solid interface impedance between the unmodified LLZO solid electrolyte and the anode is not as good as that between the unmodified LLZO solid electrolyte and the cathode, so that the impedance between the anode and the cathode and the diaphragm is larger, the capacity exertion and the cycle performance of the battery are finally affected, and the capacity retention rate of the battery after 200 circles is 87% under the condition of 0.5 ℃ at normal temperature.
Comparative example 5 is different from example 1 in that the hot pressing process was performed only once. The separator can not be tightly attached to the positive electrode and the negative electrode and HF can not be thoroughly removed by one-time hot pressing, so that the impedance between the positive electrode and the negative electrode and the separator is large, the final battery capacity retention rate is easily influenced by the expansion of the silicon-carbon negative electrode and the separation of the separator after multiple cycles, and the battery capacity retention rate after 200 circles is 84% under the condition of normal temperature of 0.5 ℃.
The raw materials and equipment used in the invention are common raw materials and equipment in the field unless specified otherwise; the methods used in the present invention are conventional in the art unless otherwise specified.
The foregoing description is only a preferred embodiment of the present invention, and is not intended to limit the present invention, and any simple modification, variation and equivalent transformation of the above embodiment according to the technical substance of the present invention still fall within the scope of the technical solution of the present invention.
Claims (9)
1. The preparation method of the lithium battery containing the double-sided differential lithium battery diaphragm is characterized by comprising the following steps of:
1) Primary hot pressing: after the cell is packaged and injected with liquid, the cell is subjected to primary hot pressing at 75 ℃ and 0.2MPa for 10min;
2) And (3) secondary hot pressing: performing secondary hot pressing on the battery cell at 20 ℃ and 0.2MPa for 25min;
3) Standing: standing the battery cell after the secondary hot pressing;
4) Degassing: degassing the cell under vacuum;
the double-sided differential lithium battery separator comprises a polymer base film; the two sides of the polymer base film are respectively coated with an anode attaching coating and a cathode attaching coating; the positive electrode attaching coating and the negative electrode attaching coating both comprise polymer adhesive and inorganic material particles, and the adhesive force of the positive electrode attaching coating is smaller than that of the negative electrode attaching coating; the inorganic material particles comprise ceramic particles and garnet-type modified LLZO solid electrolyte;
the preparation method of the garnet-type modified LLZO solid electrolyte comprises the following steps:
a) Preparation of Al/Ga doped modified LLZO solid electrolyte: batching according to the element composition in LLZO, and adding raw materials containing Ga and Al on the basis, wherein the total doping amount of Ga and Al in the LLZO is not more than 5wt%; adding all raw materials into a three-dimensional high-energy vibration ball mill for ball milling, sintering in air at 300-400 ℃ for 1-3 hours after ball milling, cooling to room temperature at the speed of 10-20 ℃/min, continuing ball milling and mixing, and performing anaerobic sintering at 900-1100 ℃ for 6-12 hours under 300-500Mpa to prepare the Al/Ga doped modified LLZO solid electrolyte;
b) And (3) low-temperature cold sintering modification: mixing polypropylene carbonate and acetone uniformly, adding lithium perchlorate for full dissolution, adding Al/Ga doped modified LLZO solid electrolyte into the obtained mixed solution, continuing ultrasonic mixing uniformly, and sintering at a low temperature of 300-400Mpa and 100-250 ℃ to obtain garnet type modified LLZO solid electrolyte.
2. The method according to claim 1, wherein the positive electrode coating has an areal density of 0.2 to 0.8g/m 2 The surface density of the negative electrode attaching coating is 0.3-2.5g/m 2 The method comprises the steps of carrying out a first treatment on the surface of the And the surface density of the positive electrode attaching coating is smaller than that of the negative electrode attaching coating.
3. The method of manufacturing of claim 2, wherein the garnet-type modified LLZO solid electrolyte has a smaller ratio in the inorganic material particles of the positive electrode washcoat than in the inorganic material particles of the negative electrode washcoat.
4. The method of preparing of claim 3, wherein the garnet-type modified LLZO solid electrolyte comprises 15-25wt% of the inorganic material particles of the positive electrode washcoat; the garnet-type modified LLZO solid electrolyte accounts for 25-35wt% of the inorganic material particles of the negative electrode adhesion coating.
5. The method of claim 1, wherein in step a): the inner wall of the three-dimensional high-energy vibration ball mill is made of zirconia, the grinding balls are steel balls, tungsten carbide balls or polyamine peptide balls, and the ball milling conditions are as follows: ball-milling for 5-10 min at normal temperature with the ball-material ratio of 20-50:40-80; after cooling, the ball milling is continued for 10-20 minutes.
6. The method of claim 1, wherein in step B): the carbonic acid polypropylene and the acetone are ultrasonically mixed for 5-15 minutes at normal temperature according to the volume ratio of 1-3:2-5, and lithium perchlorate is added until the lithium perchlorate is completely dissolved, wherein the concentration of the lithium perchlorate is 35-55wt%.
7. The method of claim 1, wherein in step B): the mass ratio of the mixed solution to the Al/Ga doped modified LLZO solid electrolyte is (2-8) (65-80).
8. The method of claim 1, wherein in step B): adding Al/Ga doped modified LLZO solid electrolyte, continuing ultrasonic mixing for 20-40 minutes, and sintering at low temperature for 1-3 hours.
9. The method of claim 1, wherein,
the polymer binder in the positive electrode attaching coating is one or more of PVDF, PC, PMMA and PAN;
the polymer binder in the negative electrode attaching coating is one or more of PAA, PVA, EVOH and SBR;
the ceramic particles are at least one of aluminum oxide, boehmite, barium sulfate, magnesium sulfate and silicon oxide;
the polymer base membrane is one of a PE single-layer membrane, a PP single-layer membrane and a PE and PP composite multi-layer membrane.
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