Lithium aluminum titanium phosphate electrolyte material and rechargeable high-safety lithium battery

Abstract

A lithium aluminum titanium phosphate electrolyte material and a rechargeable high-safety lithium battery. The mass content of lithium aluminum titanium phosphate is 95%-100%, an electrolyte of a lithium battery comprises lithium aluminum titanium phosphate, and the chemical formula is Li1+z+3uAlzTi2-zM3u(P1-uO4)3 (abbreviated as LATP). LATP materials having large dielectric constants correspond to LATP having high lithium content, large impedance, and low capacity and retention rate. Materials having small dielectric constants correspond to LATP having low lithium content, a small amount of lithium ion migration, and low capacity and retention rate. Materials having large elastic moduli have high hardness, poor particle contact, large impedance, and low battery capacity and retention rate. Materials having small elastic moduli have low hardness, good particle contact, small impedance, and high battery capacity and retention rate. Therefore, the dielectric constant y and elastic modulus x of the rechargeable high-safety lithium battery satisfy the relationship 40<y-2.79x≤120, and the battery has high capacity and high capacity retention rate when satisfying said conditions.

Description

A lithium aluminum titanium phosphate electrolyte material and a rechargeable high-safety lithium battery

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This disclosure claims priority to Chinese patent application number 202311094835.3, filed with the Chinese Patent Office on August 29, 2023, entitled “A Rechargeable High-Safety Lithium Battery,” the entire contents of which are incorporated by reference into this disclosure. Technical Field

[0003] The present disclosure relates to the field of new energy technology, and in particular to a lithium aluminum titanium phosphate electrolyte material and a rechargeable high-safety lithium battery. Background Art

[0004] Traditional lithium-ion batteries use organic electrolytes with low ionic resistance as electrolytes. The flammability and leakage of organic electrolytes can easily lead to safety problems and low specific energy. All-solid-state batteries using solid electrolytes with non-flammable properties can avoid these problems.

[0005] The solid electrolyte lithium aluminum titanium phosphate (LiTP) offers advantages such as strong mechanical properties, excellent electrochemical performance, high ionic conductivity, and good air stability, making it promising for the preparation of high-safety, high-energy-density solid-state lithium batteries. Experiments have shown that using LiTP as a solid electrolyte, due to its thermal stability above 800°C, can improve the thermal stability and needle puncture safety of battery cells. However, some all-solid-state batteries using solid electrolytes suffer from high solid-solid interface contact resistance and poor long-cycle capacity.

[0006] Summary of the Invention

[0007] The purpose of the present disclosure includes providing a lithium aluminum titanium phosphate electrolyte material and a rechargeable high-safety lithium battery to improve or solve the above-mentioned problems.

[0008] To achieve the above objectives, the present disclosure may adopt the following technical solutions:

[0009] The present invention provides a lithium aluminum titanium phosphate electrolyte material, wherein the mass content of lithium aluminum titanium phosphate in the lithium aluminum titanium phosphate electrolyte material is 95%-100%, and the chemical formula of lithium aluminum titanium phosphate is Li 1+z+3u Al z Ti 2-z M 3u (P 1-uO4)3, wherein M is selected from any one or more of Ti, Zr, Hf, Si, Ge and Sn, 0<z<1, 0≤u≤0.2, the elastic modulus x of lithium titanium aluminum phosphate ranges from 56GPa to 95GPa, the dielectric constant y ranges from 195 to 400, and the dielectric constant y and elastic modulus x of lithium titanium aluminum phosphate satisfy the following relationship: 40<y-2.79x≤120.

[0010] In an optional embodiment, the dielectric constant y and elastic modulus x of the lithium aluminum titanium phosphate satisfy the following relationship: 50≤y-2.79x≤100.

[0011] In an optional embodiment, the elastic modulus x of the lithium aluminum titanium phosphate satisfies: 60≤x<95.

[0012] The present invention provides a rechargeable high-safety lithium battery, comprising a positive electrode, a negative electrode, and an electrolyte located between the positive electrode and the negative electrode, wherein the electrolyte comprises lithium aluminum titanium phosphate, the chemical formula of which is Li 1+z+3u Al z Ti 2-z M 3u (P 1-u O4)3 (abbreviated as LATP), wherein M is selected from any one or more of Ti, Zr, Hf, Si, Ge and Sn, 0<z<1, 0≤u≤0.2, and the dielectric constant y and elastic modulus x of lithium aluminum titanium phosphate satisfy the following relationship: 40<y-2.79x≤120.

[0013] The present invention provides a rechargeable high-safety lithium battery, which includes a positive electrode, a negative electrode and an electrolyte located between the positive electrode and the negative electrode, wherein the electrolyte includes lithium aluminum titanium phosphate, the content of lithium aluminum titanium phosphate in the electrolyte is 95%-100%, and the chemical formula of lithium aluminum titanium phosphate is Li 1+z+3u Al z Ti 2-z M 3u (P 1-u O4)3, wherein M is selected from any one or more of Ti, Zr, Hf, Si, Ge and Sn, 0<z<1, 0≤u≤0.2, the elastic modulus x of lithium titanium aluminum phosphate is in the range of 56GPa-95GPa, the dielectric constant y is in the range of 195-400, and the dielectric constant y and elastic modulus x of lithium titanium aluminum phosphate satisfy the following relationship: 40<y-2.79x≤120;

[0014] The lithium battery is a solid-state battery and / or a semi-solid-state battery. In the solid-state battery, lithium aluminum titanium phosphate is cold-pressed into sheets to obtain a solid electrolyte; in the semi-solid-state battery, lithium aluminum titanium phosphate is coated on a diaphragm.

[0015] In an optional embodiment, the dielectric constant y and elastic modulus x of lithium aluminum titanium phosphate satisfy the following relationship: 50≤y-2.79x≤100.

[0016] In an optional embodiment, the elastic modulus x of lithium aluminum titanium phosphate satisfies: 60≤x<95.

[0017] In an optional embodiment, the positive electrode active material in the positive electrode powder of the positive electrode is coated with lithium titanium aluminum phosphate, and / or the negative electrode powder of the negative electrode is doped with lithium titanium aluminum phosphate.

[0018] In an optional embodiment, the lithium battery is a lithium ion battery, and the positive electrode powder includes, by mass percentage, 80% to 99% positive electrode active material, 0.2% to 20% conductive agent, 0.2% to 20% binder and 0% to 20% additives.

[0019] In an optional embodiment, the negative electrode powder includes, by mass percentage, 80% to 99% of negative electrode active material, 0.2% to 20% of conductive agent, 0.2% to 20% of binder and 0% to 20% of additive.

[0020] In an optional embodiment, the lithium battery is a lithium-air battery, and the positive electrode powder includes: 80% to 99% positive electrode active material, 0.5% to 20% conductive agent, 0.2% to 20% binder and 0% to 20% additive.

[0021] In an optional embodiment, the lithium battery is a lithium-sulfur battery, and the positive electrode powder includes: 80% to 99% positive electrode active material, 0.2% to 20% conductive agent, 0.2% to 20% binder and 0% to 20% additive.

[0022] In an optional embodiment, the positive electrode active material is selected from one or more of: NCM, NCA, lithium-rich manganese-based materials, LFP, LiMO2, S, FeS, FeS2, Li2S, porous carbon materials, and M in LiMO2 is selected from Mn, Co or Ni.

[0023] In an optional embodiment, the negative electrode active material is selected from one or more of lithium metal, lithium alloy, graphite, Si, SiO, SiC, and LTO.

[0024] In an optional embodiment, the conductive agent is selected from one or more of: carbon black, conductive graphite, carbon fiber, carbon nanotube, graphene, carbon aerogel, and conductive carbon nitrogen compound.

[0025] In an optional embodiment, the binder is selected from one or more of polyvinylidene fluoride, polytetrafluoroethylene, carboxymethyl cellulose, styrene-butadiene rubber, methyl cellulose, methyl cellulose, polyacrylic acid, polyacrylate, and polyacrylonitrile.

[0026] In an optional embodiment, the additive is selected from one or more of oxides, sulfides, halides and polymers.

[0027] In an optional embodiment, the preparation process of the positive electrode active material coated lithium aluminum titanium phosphate includes:

[0028] Mixing the positive electrode active material with the additive and dispersing the mixture in anhydrous ethanol to obtain a positive electrode active material solution;

[0029] The lithium titanium aluminum phosphate and the positive electrode active material solution are mixed evenly, the solid content of the powder is controlled to 20%-50%, and spray drying is performed with an air inlet temperature of 200-300°C and an air outlet temperature of 100-200°C. Subsequently, heat treatment is performed in an oxygen atmosphere of 500-800°C for 2-24 hours to obtain a positive electrode active material coated with lithium titanium aluminum phosphate.

[0030] In an optional embodiment, the lithium battery includes a solid-state battery and / or a semi-solid-state battery, wherein lithium aluminum titanium phosphate is cold pressed into sheets to obtain a solid electrolyte; and wherein lithium aluminum titanium phosphate is coated on a diaphragm in a semi-solid-state battery.

[0031] In an optional embodiment, the production process of lithium aluminum titanium phosphate includes any one of dry mixing sintering, liquid phase spray sintering, sol-gel sintering, melt quenching sintering, sputtering sintering, evaporation sintering, electrospinning sintering, and gas phase / electrochemical deposition sintering.

[0032] The beneficial effects of the present disclosure include:

[0033] The rechargeable high-safety lithium battery provided by the present disclosure comprises a positive electrode, a negative electrode and lithium aluminum titanium phosphate located between the positive electrode and the negative electrode, and its chemical formula is Li 1+z+3u Al z Ti 2-z M 3u (P 1-u O4)3 (abbreviated as LATP), LATP materials with large dielectric constants correspond to high lithium content LATP (z=0.5), with large impedance, low capacity and retention rate; materials with small dielectric constants correspond to low lithium content LATP (z=0.1), with small number of lithium ion migrations, low capacity and retention rate. Materials with large elastic modulus have high hardness, poor particle contact, large impedance, low battery capacity and retention rate; materials with small elastic modulus have low hardness, good particle contact, small impedance, high battery capacity and retention rate. Solid-state lithium batteries with high capacity and capacity retention rate need to have suitable dielectric constants and elastic modulus. The dielectric constant y and elastic modulus x of the rechargeable high-safety lithium battery disclosed in the present invention satisfy the relationship 40<y-2.79x≤120. Solid-state lithium batteries that meet this condition have high capacity and high capacity retention rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the technical solutions of the embodiments of the present disclosure, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present disclosure and therefore should not be regarded as limiting the scope of the present disclosure.

[0035] FIG1 is a SEM image of the LATP-1 solid electrolyte of Example 1;

[0036] FIG2 is a cross-sectional SEM image of the NCM-L composite material of LATP-1 coated with NCM9055 of Example 1;

[0037] Figure 3 is an enlarged view of Figure 2;

[0038] FIG4 is a SEM image of the LATP-3 coated NCM9055 positive electrode of Example 3;

[0039] FIG5 is a cross-sectional SEM image of the LATP-3 coated NCM9055 positive electrode of Example 3;

[0040] Figure 6 is a SEM image of the PE separator;

[0041] FIG7 is a cross-sectional SEM image of the LATP-PVDF double-layer coated PE separator of Example 4;

[0042] FIG8 is an enlarged cross-sectional view of FIG7 ;

[0043] FIG9 is a diagram showing the relationship between the elastic modulus and dielectric constant of LATP-based inorganic solid electrolytes;

[0044] Figure 10 is the constant current charge and discharge curve of Li-LATP@C in Example 3;

[0045] FIG11 is an XRD diffraction pattern of the LATP nanomaterial prepared in Example 3;

[0046] FIG12 is an XRD diffraction pattern of LATP-coated NCM9055 of Examples 1-4;

[0047] Figures 13 to 15 are XPS spectra of LATP-coated NCM9055 materials in Examples 1-3. DETAILED DESCRIPTION

[0048] As used herein:

[0049] "Prepared from" is synonymous with "comprising." As used herein, the terms "comprising," "including," "having," "containing," or any other variations thereof, are intended to cover a non-exclusive inclusion. For example, a composition, process, method, article, or apparatus that comprises the listed elements is not necessarily limited to only those elements but may include other elements not expressly listed or inherent to such composition, process, method, article, or apparatus.

[0050] The conjunction "consisting of" excludes any unspecified element, step, or component. If used in a claim, this phrase renders the claim closed, excluding materials other than those described, except for conventional impurities associated therewith. When the phrase "consisting of" appears in a clause of the body of a claim, rather than immediately following the subject matter, it limits only the elements described in that clause; other elements are not excluded from the claim as a whole.

[0051] When an amount, concentration, or other value or parameter is expressed as a range, a preferred range, or a range defined by a series of upper preferred values ​​and lower preferred values, this should be understood as specifically disclosing all ranges formed by any pairing of any range upper limit or preferred value with any range lower limit or preferred value, regardless of whether the range is disclosed alone. For example, when a range of "1 to 5" is disclosed, the described range should be interpreted as including the range "1 to 4", "1 to 3", "1 to 2", "1 to 2 and 4 to 5", "1 to 3 and 5", etc. When a numerical range is described herein, unless otherwise stated, the range is intended to include its end values ​​and all integers and fractions within the range.

[0052] In these examples, parts and percentages are by mass unless otherwise indicated.

[0053] "Parts by mass" refers to the basic unit of measurement used to express the mass ratio of multiple components. One part can represent any unit of mass, such as 1g or 2.689g. If we say that the mass of component A is a parts and the mass of component B is b parts, this means the ratio of the mass of component A to the mass of component B is a:b. Alternatively, we could say that the mass of component A is aK and the mass of component B is bK (K is an arbitrary number representing a multiplication factor). It's important to note that, unlike parts by mass, the sum of the mass of all components is not limited to 100 parts.

[0054] "And / or" is used to indicate that one or both of the stated situations may occur, for example, A and / or B includes (A and B) and (A or B).

[0055] The embodiments of the present disclosure will be described in detail below with reference to specific examples. However, those skilled in the art will appreciate that the following examples are intended only to illustrate the present disclosure and should not be construed as limiting the scope of the present disclosure. Where specific conditions are not specified in the examples, conventional conditions or conditions recommended by the manufacturer were used. Reagents or instruments used where the manufacturer is not specified are conventional products that can be purchased commercially.

[0056] Example 1

[0057] 1) Using VC mixed high temperature solid phase reaction method to prepare chemical formula Li 1.4 Al 0.4 Ti 1.6 The preparation steps of lithium aluminum titanium phosphate (PO4)3 solid electrolyte powder include: selecting LiOH (or Li2CO3), Al2O3, TiO2 and NH4H2PO4 as raw materials according to the molar ratio of Li, Al, Ti and P being 1.6:0.4:1.6:3, wherein LiOH (or Li2CO3) is in excess of 15wt%, and the raw materials are fully mixed in a VC mixer; then calcining at 850°C for 12 hours at a heating rate of 4°C / min, and after sintering, crushing, grinding (ball milling and sand milling), drying, sieving and dehydrating the powder to obtain 300nm Li 1.4 Al 0.4 Ti 1.6 The (PO4)3 powder is denoted as LATP-1, and its SEM image is shown in Figure 1.

[0058] 2) NCM9055, LATP-1, and Al2O3 were mixed in a ratio of 98:1:1 and heat-treated at 550°C in an oxygen atmosphere for 12 hours to obtain an NCM-L composite material consisting of LATP-1 coated NCM9055. The cross-sectional SEM image is shown in Figure 2, and Figure 3 is an enlarged view of the sphere in Figure 2. NCM-L, Super P, and PVDF were then weighed in a ratio of 95:3:2 and ground to form the positive electrode active material. Graphite, LATP-1, acetylene black, CMC, and SBR were weighed in a ratio of 95:0.5:2.5:1:1 and ground thoroughly to form the negative electrode active material.

[0059] 3) Weigh an appropriate amount of LATP-1 powder and cold-press it at a pressure of 50 MPa for 1 minute to obtain a sheet with a diameter of 14 mm and a thickness of 500 μm. Place the positive and negative active materials on both sides of the LATP-1 sheet and spread them evenly. The surface density of the positive and negative active materials is 2 mg / cm, respectively. 2 and 3mg / cm 2 The sample was then placed into a Swagelok mold with a mold pressure of 5 Nm and subjected to a constant current charge and discharge test. The constant current charge and discharge voltage range was 2.0V-4.3V and the current was 0.05C.

[0060] Example 2

[0061] 1) Liquid spray mixing high temperature solid phase reaction method was used to prepare Li 1.6 Al 0.4 Ti 1.6 Si 0.2 (P 0.93The preparation steps of lithium silicotitanium aluminum phosphate solid electrolyte powder include: selecting LiOH (or Li2CO3), Al2O3, SiO2, TiO2 and NH4H2PO4 as raw materials according to the molar ratio of Li, Al, Ti, Si and P being 1.8:0.4:1.6:0.2:2.8, wherein LiOH (or Li2CO3) is in excess of 15wt%, and spray drying is performed after being fully mixed in a ball mill, with an inlet temperature of 220°C and an outlet temperature of 120°C to obtain a LATSP precursor; and then calcining at 850°C for 12 hours with a heating rate of 4°C / min. After sintering, the powder is crushed, ground (ball milling and sand milling), dried, sieved and dehydrated to obtain 350nm Li 1.6 Al 0.4 Ti 1.6 Si 0.2 (P 0.93 O4)3 powder, recorded as LATP-2.

[0062] 2) NCM9055, LATP-2, ZrO2, and Al2O3 were mixed in a ratio of 98:1:0.5:0.5 and heat-treated at 600°C in an oxygen atmosphere for 12 hours to obtain an NCM-L composite material consisting of LATP-2 coated NCM9055. NCM-L, Super P, and PVDF were weighed in a ratio of 95:3:2 and ground to form the positive electrode active material. Graphite, LATP-2, acetylene black, CMC, and SBR were weighed in a ratio of 95:0.5:2.5:1:1 and ground thoroughly to form the negative electrode active material.

[0063] 3) Weigh an appropriate amount of LATP-2 powder and cold-press it at a pressure of 50 MPa for 1 minute to obtain a sheet with a diameter of 14 mm and a thickness of 500 μm. Place the positive and negative active materials on both sides of the LATP-2 sheet and spread them evenly. The surface density of the positive and negative active materials is 2 mg / cm, respectively. 2 and 3mg / cm 2 The sample was then placed into a Swagelok mold with a mold pressure of 5 Nm and subjected to a constant current charge and discharge test. The constant current charge and discharge voltage range was 2.0V-4.3V and the current was 0.05C.

[0064] Example 3

[0065] 1) Prepare Li 1.8 Al 0.4 Ti 1.6 Zr 0.4 (P 0.86The preparation steps of lithium zirconium titanium aluminum phosphate solid electrolyte powder include: selecting LiNO3, Al(NO3)39H2O, Ti(OC4H9)4, Zr(NO3)4 and NH4H2PO4 as raw materials according to the molar ratio of Li, Al, Ti, Zr and P being 2.0:0.4:1.6:0.4:2.6, wherein LiNO3 is in excess of 10wt%, citric acid is used as a chelating agent, and ammonia water is used as a pH adjuster, and the mixture is stirred and mixed in an 80°C water bath to obtain a LATP-3 precursor; and then calcining at 700°C for 8 hours with a heating rate of 4°C / min, and after sintering, crushing, grinding (ball milling and sand milling), drying, sieving and dehydrating the powder to obtain 250nm Li 1.8 Al 0.4 Ti 1.6 Zr 0.4 (P 0.86 O4)3 powder, recorded as LATP-3.

[0066] 2) NCM9055, TiO2, and Al2O3 were dispersed in ethanol at a ratio of 98:0.5:0.5 and thoroughly stirred. The mixture was then ball-milled with 1 wt% LATP-3 precursor and spray-dried to a powder solid content of 40%. The inlet temperature was 220°C and the outlet temperature was 120°C. The mixture was then heat-treated at 700°C in an oxygen atmosphere for 12 hours to obtain an NCM-L composite material in which LATP-3 was in situ coated with NCM9055. The SEM image of the composite material is shown in Figure 4, and the SEM image of the cross-section is shown in Figure 5. NCM-L, Super P, and PVDF were then weighed at a ratio of 95:3:2 and ground to form the positive electrode active material.

[0067] 3) Weigh an appropriate amount of LATP-3 powder and cold press it into sheets at a pressure of 30 MPa for 1 minute to obtain sheets with a diameter of 14 mm and a thickness of 500 μm. Place the positive electrode active material from step 2 on one side of the LATP-3 sheet and spread it evenly. The surface density of the positive electrode active material is 2 mg / cm 2 , maintaining pressure at 60 MPa for 1 minute. Next, a 12mm diameter, 50μm thick lithium sheet was added to the other side of the LATP-3 sheet and cold pressed at 300 MPa for 10 minutes. The sample was then placed into a Swagelok mold battery with a mold pressure of 5 Nm and subjected to constant current charge and discharge testing. The constant current charge and discharge voltage range was 2.0V-4.3V, and the current was 0.05C.

[0068] Example 4

[0069] 1) Using VC mixed high temperature solid phase reaction method to prepare chemical formula Li 1.3 Al 0.3 Ti 1.7The preparation steps of lithium aluminum titanium phosphate (PO4)3 solid electrolyte powder include: selecting LiOH (or Li2CO3), Al2O3, TiO2 and NH4H2PO4 as raw materials according to the molar ratio of Li, Al, Ti and P of 1.5:0.3:1.7:3, wherein LiOH (or Li2CO3) is in excess of 15wt%, and the raw materials are fully mixed in a VC mixer; then calcining at 850°C for 12 hours with a heating rate of 4°C / min, and after sintering, crushing, grinding (ball milling and sand milling), drying, sieving and dehydrating the powder to obtain 300nm Li 1.3 Al 0.3 Ti 1.7 (PO4)3 powder, recorded as LATP-4.

[0070] 2) NCM9055, LATP-4, ZrO2, and Al2O3 were mixed in a ratio of 98:1:0.6:0.4 and heat-treated at 650°C in an oxygen atmosphere for 12 hours to obtain an NCM-L composite material consisting of LATP-4 coated NCM9055. NCM-L, Super P, and PVDF were then weighed in a ratio of 95:3:2, dispersed in an NMP slurry, coated on aluminum foil, and vacuum-dried at 80°C for 12 hours to prepare the positive electrode. Graphite, LATP-4, acetylene black, CMC, and SBR were weighed in a ratio of 95:0.5:2.5:1:1, dispersed into an aqueous slurry, coated on copper foil, and vacuum-dried at 100°C for 12 hours to prepare the negative electrode.

[0071] 3) Weigh appropriate amounts of LATP-4, CMC, SBR, and wetting agent and disperse them in water at a ratio of 95:1.5:1.5:2 to prepare an aqueous slurry with a solid content of 35%. After ball milling, the above slurry is coated on a commercial PE separator. The SEM image of the PE separator is shown in Figure 6. The separator thickness is 10μm and the LATP coating thickness is about 2μm. A layer of 1μm thick PVDF film is coated on the LATP coating to improve the adhesion between the battery separator and the positive and negative electrodes. The cross-sectional SEM image of the LATP-PVDF double-layer coated PE separator is shown in Figure 7, and its cross-sectional enlarged view is shown in Figure 8. Finally, it is fully dried at 80°C to obtain a LATP-coated separator with a thickness of 14.5μm. CR232 button cells were assembled using the aforementioned positive electrode, the LATP-coated separator (facing the positive electrode), and the negative electrode. The positive and negative electrode diameters were 15 mm, the separator diameter was 20 mm, and the electrolyte was 1 mol / L LiPF6-EC / DEC / EMC. 1C constant current charge and discharge tests were performed over a voltage range of 2.5 V to 4.3 V at a current of 1C.

[0072] Example 5

[0073] 1) Using VC mixed high temperature solid phase reaction method to prepare chemical formula Li1.7 Al 0.4 Ti 1.6 Si 0.3 (P 0.9 The preparation steps of lithium silicotitanium aluminum phosphate solid electrolyte powder include: selecting LiOH (or Li2CO3), Al2O3, SiO2, TiO2 and NH4H2PO4 as raw materials according to the molar ratio of Li, Al, Ti, Si and P of 2.0:0.4:1.6:0.3:2.7, wherein LiOH (or Li2CO3) is in excess of 15wt%, and the raw materials are fully mixed in a VC mixer; then calcining at 900°C for 12 hours with a heating rate of 4°C / min, and after sintering, crushing, grinding (ball milling and sand milling), drying, sieving and dehydrating the powder to obtain 280nm Li 1.7 Al 0.4 Ti 1.6 Si 0.3 (P 0.9 O4)3 powder, recorded as LATP-5.

[0074] 2) Nano-LATP-5 powder was added to a 5% sucrose aqueous solution, stirred at 1000 rpm for 5 hours, and dried at 100°C. Subsequently, it was heat-treated at 850°C under a nitrogen atmosphere for 12 hours to obtain a LATP-coated LATP-C composite material. KB600, LATP-C, Co3O4, multi-walled CNTs, and PVDF were weighed in a 93:3:2:1:1 ratio and dispersed in an NMP slurry. After thorough stirring, the slurry was coated onto porous carbon-coated Al foil and dried in a vacuum oven at 80°C for 12 hours to prepare the positive electrode.

[0075] 3) Appropriate amounts of LATP-5, CMC, SBR, and wetting agent were weighed and dispersed in water at a ratio of 95:1.5:1.5:2 to prepare an aqueous slurry with a solids content of 35%. After ball milling, the slurry was coated onto a commercial Celgard separator with a thickness of 20 μm and a LATP coating of approximately 2 μm. A 1 μm thick PVDF membrane was applied over the LATP coating to improve adhesion between the separator and the positive and negative electrodes. Finally, the LATP-coated separator was fully dried at 80°C to a thickness of 14.5 μm. CR232 button cells (with porous positive electrode casings) were assembled using the aforementioned positive electrode sheet, the coated LATP separator (facing the positive electrode sheet), and a lithium metal anode. The positive and negative electrodes had a diameter of 15 mm, the separator had a diameter of 20 mm, and the electrolyte was 1 mol / L LiTFSI-TEG / DME. A 1C constant current charge-discharge test was performed in an oxygen atmosphere (humidity <10%). The constant current charge and discharge voltage range is 2.0V-4.5V, and the current is 1C.

[0076] Example 6

[0077] 1) Using VC mixed high temperature solid phase reaction method to prepare chemical formula Li 1.6 Al 0.4 Ti 1.6 Ge 0.2 (P 0.93 The preparation steps of the lithium germanium titanium aluminum phosphate solid electrolyte powder include: selecting LiOH (or Li2CO3), Al2O3, GeO2, TiO2 and NH4H2PO4 as raw materials according to the molar ratio of Li, Al, Ti, Ge and P being 1.8:0.4:1.6:0.2:2.8, wherein LiOH (or Li2CO3) is in excess of 15wt%, and the raw materials are fully mixed in a VC mixer; then calcining at 900°C for 12 hours with a heating rate of 4°C / min, and after the sintering is completed, crushing, grinding (ball milling and sand milling), drying, sieving and dehydrating the powder to obtain 320nm Li 1.6 Al 0.4 Ti 1.6 Ge 0.2 (P 0.93 O4)3 powder, recorded as LATP-6.

[0078] 2) Nano-LATP-6 powder was added to a 5% aqueous citric acid solution, stirred at 2000 rpm for 5 hours, and dried at 100°C. This was then heat-treated at 850°C in a nitrogen atmosphere for 12 hours to obtain a LATP-coated LATP-C composite material. S and KB carbon were ground evenly in a 3:1 ratio and then heat-treated at 155°C in a vacuum tube furnace for 24 hours to obtain a SC active material with a 60% S content. SC, LATP-C, multi-walled CNTs, and PVDF were then weighed in a 93:3:2:2 ratio, dispersed in an NMP slurry, thoroughly stirred, and coated onto a porous carbon-coated Al foil. The resulting material was then vacuum-dried at 80°C for 12 hours to prepare the positive electrode.

[0079] 3) Appropriate amounts of LATP-6, cellulose acetate, and a wetting agent were weighed and dispersed in water at a ratio of 95:3:2 to prepare an aqueous slurry with a solid content of 35%. After ball milling, the slurry was coated onto a commercial PE separator with a thickness of 12 μm and a LATP coating of approximately 2 μm. A 1 μm thick PVDF membrane was applied over the LATP coating to improve adhesion between the separator and the positive and negative electrodes. Finally, the LATP-coated separator was fully dried at 80°C to a thickness of 14.5 μm. CR232 button cells were assembled using the aforementioned positive electrode sheet, the coated LATP separator (facing the positive electrode sheet), and a lithium metal negative electrode. The positive and negative electrode diameters were 15 mm, the separator diameter was 20 mm, and the electrolyte was 1 mol / L LiTFSI-DME / DOL + 0.2% LiNO3. The electrolyte was in excess, and a 1C constant current charge and discharge test was performed. The constant current charge and discharge voltage range was 1.7 V to 3.2 V, and the current was 1C.

[0080] Example 7

[0081] Same as Example 4, the positive electrode is not coated with Al2O3, ZrO2, or LATP, and the negative electrode is not mixed with LATP. Other aspects remain the same, wherein the LATP material is selected with an Al content of z=0.4 and u=0 (Li 1+z+3u Al z Ti 2-z M 3u (P 1-u O4)3, 0<z<1, 0≤u≤0.2).

[0082] Comparative Example 1

[0083] The difference between Comparative Example 1 and Example 1 is that during the preparation of the lithium aluminum titanium phosphate solid electrolyte powder, the sintering condition is calcination at 950° C. for 12 h, and the remaining steps are the same as those in Example 1.

[0084] Comparative Example 2

[0085] The difference between Comparative Example 2 and Example 2 is that the chemical formula of LATP material is Li 2.0 Al 0.4 Ti 1.6 Sn 0.6 (P 0.8 O4)3, and the remaining steps are the same as in Example 2.

[0086] Comparative Example 3

[0087] The difference between Comparative Example 3 and Example 3 is that the particle size of the LATP material is 1200 nm, and the remaining steps are the same as those of Example 3.

[0088] Comparative Example 4

[0089] The difference between Comparative Example 4 and Example 4 is that the chemical formula of LATP material is Li 1.8 Al 0.5 Ti 1.5 Ge 0.3 (P 0.9 O4)3, and the remaining steps are the same as in Example 4.

[0090] Comparative Example 5

[0091] The difference between Comparative Example 5 and Example 5 is that the chemical formula of LATP material is Li 1.4 Al 0.1 Ti 1.9 Si 0.3 (P 0.9 O4)3, and the remaining steps are the same as in Example 5.

[0092] Comparative Example 6

[0093] The difference between Comparative Example 6 and Example 6 is that during the preparation of lithium aluminum titanium phosphate solid electrolyte powder, ammonium dihydrogen phosphate in the raw material is replaced by titanium pyrophosphate, and the chemical formula of LATP material is Li 1.4 Al 0.2 Ti 1.8 Ge 0.2 (P 0.94 O4)3, and the remaining steps are the same as in Example 6.

[0094] Comparative Example 7

[0095] The difference between Comparative Example 7 and Example 7 is that the chemical formula of LATP material is Li 1.4 Al 0.3 Ti 1.7 Sn 0.1 (P 0.97 O4)3, and the remaining steps are the same as in Example 7.

[0096] Test example

[0097] The LATP materials obtained in the above Examples 1-7 and Comparative Examples 1-7 were tested for phase, conductivity, elastic modulus, dielectric constant and electrical performance, and the test methods were as follows:

[0098] 1. Appearance

[0099] According to GB / T 16594-2008, the morphology and cross-section of the LATP powder, LATP-coated positive electrode powder, and LATP-coated separator in Examples 1-7 and Comparative Examples 1-7 were analyzed using a scanning electron microscope.

[0100] 2. Physical phase test

[0101] XRD and XPS tests were performed on the LATP and LATP-coated cathode powders prepared by different processes in Examples 1-7 and Comparative Examples 1-7 to observe the phase changes before and after coating. XRD test: 1g of the sample powder to be tested was spread flat on a glass stage, using Cu target Kα radiation (λ = 0.15406nm), with a scanning angle of 10-90° and a scanning rate of 10° per minute. XPS test: ESCALAB 250 (vacuum degree < 2×10 -9mbar) XPS (X-ray photoelectron spectrometer), brand is Thermo Fisher Scientific. X-ray light source used: monochromatized Al Kα source (Mono AlKα) energy: 1486.6eV, 15kV 150W, beam spot size: 500μm; scanning mode: CAE; lens mode: Large Area XL. Qualitative and quantitative analysis adopts Wagner (Al target) Library. Full spectrum scan: pass energy is 70eV; narrow spectrum scan: pass energy is 20eV. Charge correction: energy correction is performed based on surface contamination C1s (284.8eV). XPS test requirements: the sample surface is flat, the conductivity is good, the size should not be too large, generally should not be larger than 10mm×10mm×5mm. The test elements include C, Ni, Co, Mn, Li, Ti, P, Al, O, etc., and the three elements Ni, Ti, and P are particularly observed.

[0102] 3. Conductivity test

[0103] AC impedance tests were performed on LATP materials prepared by different processes. The test equipment was a BioLogic electrochemical workstation. In the EC-Lab software, the following selections were made: the test frequency was 1000000-0.01Hz, the amplitude was 5mA, and each sample was tested in parallel 3 times. Sample preparation: 0.5g of dry LATP powder was taken and pressed into a sheet at 300MPa for 1min under a 15mm diameter mold, maintaining the sheet thickness at 1-2mm, heat treated at 850℃ for 10h, cooled to room temperature and vacuum sealed for storage, with a density of >90%. The LATP sheet was evenly gold-plated on both sides, and then the AC impedance spectrum was tested on the EC-Lab. A swagelok mold (with the inner wall made of Teflon insulating material) was selected, and the two ends of the LATP sheet were connected with stainless steel sheets. The torque wrench was set to a pressure of 5mN. According to the formula δ=l / (RS), where l and S are the sheet thickness and surface area, respectively, R is the test AC impedance value, and δ is the lithium ion conductivity.

[0104] 4. Dielectric constant test

[0105] LATP powder was dried at 200℃ under vacuum for more than 24 hours, pressed into sheets at 300MPa for 1 minute in a 15mm diameter die, maintaining a sheet thickness of 1-2mm, heat treated at 850℃ for 10 hours, cooled to room temperature and stored in a vacuum seal. The density was >90%. Dielectric constant test: LATP sheets were gold-plated on both sides, with a gold-plated area of ​​S = 50.24mm 2 , thickness 1.5mm, use Agilent4294A impedance tester to perform room temperature dielectric constant test, the test frequency is 40-10000000Hz, and 10MHz points are selected for counting.

[0106] 5. Elastic modulus test

[0107] LATP powder is dried under vacuum at 200℃ for more than 24 hours, pressed into sheets at 300MPa for 1 minute in a 15mm diameter mold, maintaining a sheet thickness of 1-2mm, and heat treated at 850℃ for 10 hours. After cooling to room temperature, the sheet is sealed and stored in a vacuum chamber with a density of >90%. Elastic modulus test: The LATP sheet sample is tested for its compression elastic modulus using a hardness tester with a fixed pressure load of 20mN. The calculation formula is E=(1-V s 2 ) / (1 / E r -(1-V i 2 ) / E i ), where E is the indentation elastic modulus, E r is the elastic modulus converted from press-fit contact, E i The elastic modulus of the indenter is 1140 GPa, V i Poisson's ratio of the pressure head is 0.07, V s The Poisson's ratio is 0.28. Two surfaces and 60 points of each sample are tested. Ten samples are selected for Gaussian fitting to obtain the median elastic modulus of the samples.

[0108] 6. Power-off performance test

[0109] Assemble CR2032 button-type semi-solid-state batteries or swagelok all-solid-state batteries and test the battery cycling performance. For the NCM-Li (or graphite) system, the voltage range is 2.0-4.3V and the current is 0.05C. Calculate the capacity retention after 50 cycles. For Li-air batteries, the voltage range is 2.0V-4.5V and the current is 1C. For Li-S semi-solid-state batteries, the voltage range is 1.7V-3.2V and the current is 1C. All-solid-state batteries: 1) LATP nanopowder is cold pressed at 20MPa for 1 minute to prepare a 500μm thick solid electrolyte layer. 1) Place the conductive agent Super P, adhesive, graphite negative electrode and NCM9055 positive electrode at both ends of the LATP solid electrolyte layer and cold press or die cast at 300MPa; 2) Add a certain amount of binder, NMP, etc. to prepare the corresponding electrode slurry, apply it to both sides of the solid electrolyte (such as the LATP oxide, sulfide, polymer or combination of the above 4) and dry it, or combine it with lithium metal and lithium alloy negative electrodes (through cold pressing, thermal evaporation, magnetron sputtering or vapor deposition, etc.) to form a lithium all-solid-state battery. Semi-solid-state battery: Mix the positive and negative active materials with LATP material, conductive carbon and adhesive, apply them to Al foil or copper foil in NMP / water support slurry, and vacuum dry them to prepare the positive and negative electrodes. The above positive and negative electrode sheets and LATP are coated with a separator, and a semi-solid-state battery is assembled using a commercial electrolyte of the corresponding system or combined with a polymer.

[0110] The test results of the physical phase, electrical conductivity, elastic modulus and dielectric constant of the LATP materials of Examples 1-7 and Comparative Examples 1-7 are shown in Table 1, and the buckling performance test results are shown in Table 2. The relationship between the elastic modulus and dielectric constant of the LATP-based inorganic solid electrolyte is shown in Figure 9.

[0111] Table 1 Physicochemical properties of LATP-based inorganic solid electrolytes

[0112] According to Table 1, the LATP inorganic solid electrolyte phase purity of Examples 1-7 and Comparative Examples 1-7 is greater than 99%, the lithium ion conductivity is greater than 1E-4S / cm, the elastic modulus x ranges from 56GPa to 95GPa, and the dielectric constant y ranges from 195 to 400. The composite function F(x,y)=y-2.79x corresponding to each sample of Examples 1-7 and Comparative Examples 1-7, wherein Example 1-7 satisfies 50≤F(x,y)≤100, while Comparative Example 1-7 does not satisfy the above functional relationship. It can be clearly seen from Figure 1 that the data points of each sample composition in Examples 1-7 all fall between the two straight lines composed of F(x,y), while the data points of each sample composition in Comparative Examples 1-7 all fall outside its interval.

[0113] Table 2. Electrical properties of LATP-based inorganic solid electrolyte-coated separators

[0114] According to Table 2 above, Examples 1-4 and Comparative Examples 1-4 correspond to ternary-lithium button batteries (2032 model), wherein Example 1-3 is an all-solid-state lithium ion battery, and Examples 4 and 7 are semi-solid-state lithium metal batteries. Examples 5-6 and Comparative Examples 5-6 correspond to semi-solid-state batteries, namely Li-Air batteries and Li-S batteries, respectively. As shown in Table 2, the initial specific capacity and first efficiency of Examples 1-3 and Comparative Examples 1-3 are relatively close, while the initial specific capacity and first efficiency of Comparative Examples 4-7 are slightly lower than those of Examples 4-7, which may be attributed to their lower lithium ion conductivity. After 50 cycles, the discharge specific capacity retention rates of Examples 1-7 are all >92%, while the discharge specific capacity retention rates of Comparative Examples 1-7 are all <90%. The large difference in the above capacity retention rates is attributed to the fact that the dielectric constant and elastic modulus of the LATP inorganic solid electrolytes of Comparative Examples 1-7 do not satisfy the composite function F(x, y) = y-2.79x.

[0115] As mentioned above, LATP (lithium aluminum titanium phosphate, (Li 1+z+3u Al z Ti 2-z M 3u (P 1-uThe elastic modulus E (denoted as x) and dielectric constant ε (denoted as y) of oxide solid electrolyte materials (e.g., O4)3, M = Ti, Zr, Hf, Si, Ge, Sn, etc., 0 < z < 1, 0 ≤ u ≤ 0.2) are combined into a mechanically related composite function F(x, y), and it is found that both affect battery capacity decay. LATP materials with large dielectric constants (y), corresponding to high lithium content LATP (z = 0.5), have low room temperature lithium ion conductivity, resulting in low capacity and retention. Materials with small dielectric constants (y), corresponding to low lithium content LATP (z = 0.1), have a small number of lithium ion migrations, and low capacity and retention. Materials with large elastic modulus (x) have high hardness, poor particle contact, high impedance, and low battery capacity and retention. Materials with small elastic modulus (x) have low hardness, good particle contact, low impedance, and high battery capacity and retention.

[0116] Therefore, a solid-state lithium battery with high capacity and high capacity retention should have an appropriate dielectric constant and elastic modulus, preferably within the range of 49.54 ≤ F(x, y) = y - 2.79x ≤ 100.95. According to literature, a separator's resistance to lithium dendrites requires an elastic modulus E > 5 GPa. LATP-based materials typically have an elastic modulus greater than 50 GPa, so a lower value is preferred to increase elastic contact between solid electrolyte particles. The dielectric constant should also be appropriately small, as this will weaken the LATP material's lithium ion conductivity.

[0117] As shown in Figures 4 and 5, the LATP-3 solid electrolyte of Example 3 was spray-coated on the NCM9055 cathode, resulting in a relatively uniform and dense coating with a thickness of approximately 300 nm. The cathode maintained a relatively good spherical morphology, ensuring good contact between particles and low impedance. Figure 10 shows the constant current charge and discharge curve of the Li-LATP@C in Example 3. It can be seen that after the positive electrode is coated with LATP, the LATP itself can provide an active capacity of 100-120 mAh / g at around 2.5V, thereby replenishing lithium at the positive electrode and contributing to the initial capacity and initial efficiency of the battery.

[0118] The use of LATP-3 solid electrolyte with an elastic modulus E of x = 65GPa is homogeneous with the LATP coated / blended with the positive and negative electrodes, which can greatly reduce the contact impedance between the solid electrolyte membrane and the positive electrode and the graphite negative electrode. In addition, the high lithium content LATP (1 mol LATP contains 1.8 mol Li) coated positive electrode can replenish lithium to the positive electrode, ultimately improving the initial specific capacity and coulombic efficiency, achieving 0.05C, and a 50-cycle capacity retention rate of up to 96.04%. Example 3 is superior to Examples 1 and 2, mainly because the elastic modulus of the solid electrolytes of Examples 1 and 2 is relatively large, and the positive electrode is not completely coated with the solid electrolyte, as shown in Figures 1-3; Example 3 is even better than Comparative Examples 1-3, mainly because the elastic modulus of the solid electrolytes of Comparative Examples 1-3 is relatively large, and the dielectric constant is too large or too small.

[0119] In Examples 4-7, the lithium semi-solid-state battery constructed using an LATP-coated separator exhibits excellent electrolyte wettability compared to a PE separator, reducing electrolyte usage to approximately two-thirds of the conventional amount, improving safety and enabling a gradual transition to all-solid-state batteries. Furthermore, the PTFE layer on the surface of the LATP-coated separator increases adhesion between the separator and the positive electrode, significantly reducing contact resistance between the separator and the positive electrode, mitigating electrode expansion during charge and discharge, resisting lithium dendrites, and improving cycle capacity retention.

[0120] As shown in Example 7, using a common ternary positive electrode and a LATP-coated separator, the capacity retention rate of the lithium semi-solid battery after 50 cycles is significantly higher than that of Comparative Example 7, the dielectric constant and elastic modulus of the latter are outside the required range of this solution.

[0121] As shown in Comparative Examples 5 and 6, LATP-5 and LATP-6 inorganic solid electrolytes have a low elastic modulus, x < 65 GPa. However, the Li-air battery and Li-S battery composed of the two do not satisfy the relationship between the dielectric constant y and the elastic modulus x 49.54 ≤ F (x, y) = y-2.79x ≤ 100.95, which aggravates the polarization of the porous air positive electrode or the shuttling of polysulfide ions. Ultimately, the capacity retention rate of Comparative Examples 5 and 6 is less than 85%.

[0122] Figure 11 shows the XRD diffraction pattern of the LATP nanomaterial prepared in Example 3, while Figure 12 shows the XRD diffraction pattern of the LATP-coated NCM9055 from Examples 1-4. The patterns reveal that LATP is a nearly pure phase, with no other impurity peaks observed. Furthermore, no peaks attributable to LATP were observed after LATP coating NCM9055, likely due to its low content (1%).

[0123] Figures 13 to 15 show the XPS spectra of the LATP-coated NCM9055 materials in Examples 1-3. Using XPS, we can observe the presence of LATP signals in all of Examples 1-3. Therefore, LATP-coated cathodes combined with LATP-coated separators also achieve high capacity retention in semi-solid-state battery systems.

[0124] In summary, LATP (lithium aluminum titanium phosphate, (Li 1+z+3u Al z Ti 2-z M 3u (P 1-u The elastic modulus E (denoted as x) and dielectric constant ε (denoted as y) of the oxide solid electrolyte material (e.g., O4)3, M = Ti, Zr, Hf, Si, Ge, Sn, etc., 0 < z < 1, 0 ≤ u ≤ 0.2) are combined into a composite function F(x, y) related to mechanics. When F(x, y) is within a certain range: 50 ≤ F(x, y) = y - 2.79 x ≤ 100, and the positive and negative electrode structures are preferably coated or doped with LATP, the battery has the highest capacity and capacity retention rate (capacity retention rate > 92% after 50 cycles).

[0125] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present disclosure, rather than to limit them. Although the present disclosure has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present disclosure.

[0126] Furthermore, those skilled in the art will appreciate that although some embodiments herein include certain features included in other embodiments but not other features, the combination of features from different embodiments is intended to be within the scope of this disclosure and to form different embodiments. For example, in the claims above, any of the claimed embodiments may be used in any combination. The information disclosed in this background section is intended solely to enhance understanding of the overall background of this disclosure and should not be construed as an admission or any form of implication that such information constitutes prior art already known to those skilled in the art. Industrial Applicability

[0127] The dielectric constant y and elastic modulus x of the rechargeable high-safety lithium battery provided by the present disclosure satisfy the relationship 40<y-2.79x≤120, and has high capacity and high capacity retention rate.

Claims

1. A lithium aluminum titanium phosphate electrolyte material, characterized in that: The mass content of lithium titanium aluminum phosphate in the lithium titanium aluminum phosphate electrolyte material is 95%-100%, and the chemical formula of the lithium titanium aluminum phosphate is Li 1+z+3u Al z Ti 2-z M 3u (P 1-u O4)3, wherein M is selected from any one or more of Ti, Zr, Hf, Si, Ge and Sn, 0<z<1, 0≤u≤0.2, the elastic modulus x of the lithium titanium aluminum phosphate ranges from 56GPa to 95GPa, the dielectric constant y ranges from 195 to 400, and the dielectric constant y and elastic modulus x of the lithium titanium aluminum phosphate satisfy the following relationship: 40<y-2.79x≤120.

2. The lithium aluminum titanium phosphate electrolyte material according to claim 1, characterized in that The dielectric constant y and elastic modulus x of the lithium aluminum titanium phosphate satisfy the following relationship: 50≤y-2.79x≤100.

3. The rechargeable high-safety lithium battery according to claim 1 or 2, characterized in that: The elastic modulus x of the lithium aluminum titanium phosphate satisfies: 60≤x<95.

4. A rechargeable high-safety lithium battery, comprising a positive electrode, a negative electrode and an electrolyte located between the positive electrode and the negative electrode, characterized in that: The electrolyte includes lithium aluminum titanium phosphate, the chemical formula of which is Li 1+z+3u Al z Ti 2-z M 3u (P 1-u O4)3, wherein M is selected from any one or more of Ti, Zr, Hf, Si, Ge and Sn, 0<z<1, 0≤u≤0.2, and the dielectric constant y and elastic modulus x of the lithium titanium aluminum phosphate satisfy the following relationship: 40<y-2.79x≤120.

5. A rechargeable high-safety lithium battery, characterized in that: The invention comprises a positive electrode, a negative electrode and an electrolyte located between the positive electrode and the negative electrode, wherein the electrolyte comprises lithium titanium aluminum phosphate, the content of the lithium titanium aluminum phosphate in the electrolyte is 95%-100%, and the chemical formula of the lithium titanium aluminum phosphate is Li 1+z+3u Al z Ti 2-z M 3u (P 1-u O4)3, wherein M is selected from any one or more of Ti, Zr, Hf, Si, Ge and Sn, 0<z<1, 0≤u≤0.2, the elastic modulus x of the lithium titanium aluminum phosphate is in the range of 56GPa-95GPa, the dielectric constant y is in the range of 195-400, and the dielectric constant y and elastic modulus x of the lithium titanium aluminum phosphate satisfy the following relationship: 40<y-2.79x≤120; The lithium battery is a solid-state battery and / or a semi-solid-state battery. In the solid-state battery, the lithium aluminum titanium phosphate is cold-pressed into sheets to obtain a solid electrolyte; in the semi-solid-state battery, the lithium aluminum titanium phosphate is coated on a diaphragm.

6. The rechargeable high-safety lithium battery according to claim 4 or 5, characterized in that: The dielectric constant y and elastic modulus x of the lithium aluminum titanium phosphate satisfy the following relationship: 50≤y-2.79x≤100.

7. The rechargeable high-safety lithium battery according to any one of claims 4 to 6, characterized in that: The elastic modulus x of the lithium aluminum titanium phosphate satisfies: 60≤x<95.

8. The rechargeable high-safety lithium battery according to any one of claims 4 to 7, characterized in that: The positive electrode active material in the positive electrode powder of the positive electrode covers the lithium titanium aluminum phosphate, and / or the negative electrode powder of the negative electrode is doped with the lithium titanium aluminum phosphate.

9. The rechargeable high-safety lithium battery according to claim 8, characterized in that: The lithium battery is a lithium ion battery, and the positive electrode powder comprises, by mass percentage, 80% to 99% of positive electrode active material, 0.2% to 20% of conductive agent, 0.2% to 20% of binder and 0% to 20% of additive.

10. The rechargeable high-safety lithium battery according to claim 8 or 9, characterized in that: The lithium battery is a lithium ion battery, and the negative electrode powder comprises, by mass percentage, 80% to 99% of negative electrode active material, 0.2% to 20% of conductive agent, 0.2% to 20% of binder and 0% to 20% of additive.

11. The rechargeable high-safety lithium battery according to claim 8, characterized in that: The lithium battery is a lithium-air battery, and the positive electrode powder comprises: 80% to 99% of positive electrode active material, 0.5% to 20% of conductive agent, 0.2% to 20% of binder and 0% to 20% of additive.

12. The rechargeable high-safety lithium battery according to claim 8, characterized in that: The lithium battery is a lithium-sulfur battery, and the positive electrode powder comprises: 80% to 99% of positive electrode active material, 0.2% to 20% of conductive agent, 0.2% to 20% of binder and 0% to 20% of additive.

13. The rechargeable high-safety lithium battery according to any one of claims 8 to 12, characterized in that: The positive electrode active material is selected from one or more of NCM, NCA, lithium-rich manganese-based materials, LFP, LiMO2, S, FeS, FeS2, Li2S, and porous carbon materials, and M in the LiMO2 is selected from Mn, Co or Ni.

14. The rechargeable high-safety lithium battery according to claim 10, characterized in that: The negative electrode active material is selected from one or more of lithium metal, lithium alloy, graphite, Si, SiO, SiC, and LTO.

15. The rechargeable high-safety lithium battery according to any one of claims 9 to 12, characterized in that: The conductive agent is selected from one or more of carbon black, conductive graphite, carbon fiber, carbon nanotube, graphene, carbon aerogel, and conductive carbon nitride compounds.

16. The rechargeable high-safety lithium battery according to any one of claims 9 to 12, characterized in that: The binder is selected from one or more of polyvinylidene fluoride, polytetrafluoroethylene, carboxymethyl cellulose, styrene-butadiene rubber, methyl cellulose, methyl cellulose, polyacrylic acid, polyacrylate, and polyacrylonitrile.

17. The rechargeable high-safety lithium battery according to any one of claims 9 to 12, characterized in that: The additive is selected from one or more of oxides, sulfides, halides and polymers.

18. The rechargeable high-safety lithium battery according to any one of claims 8 to 17, characterized in that: The preparation process of coating the lithium aluminum titanium phosphate with the positive electrode active material comprises: The positive electrode active material is mixed with an additive and dispersed in anhydrous ethanol to obtain a positive electrode active material solution; The lithium titanium aluminum phosphate and the positive electrode active material solution are mixed evenly, the solid content of the powder is controlled to be 20%-50%, and spray drying is performed with an air inlet temperature of 200-300°C and an air outlet temperature of 100-200°C, followed by heat treatment at 500-800°C in an oxygen atmosphere for 2-24h to obtain a positive electrode active material coated with the lithium titanium aluminum phosphate.

19. The rechargeable high-safety lithium battery according to claim 4, characterized in that: The lithium battery includes a solid-state battery and / or a semi-solid-state battery. In the solid-state battery, the lithium aluminum titanium phosphate is cold-pressed into sheets to obtain a solid electrolyte; in the semi-solid-state battery, the lithium aluminum titanium phosphate is coated on a diaphragm.

20. The rechargeable high-safety lithium battery according to any one of claims 4 to 19, characterized in that: The production process of lithium aluminum titanium phosphate includes: any one of dry mixing sintering, liquid phase spray sintering, sol-gel sintering, melt quenching sintering, sputtering sintering, evaporation sintering, electrostatic spinning sintering, and gas phase / electrochemical deposition sintering.

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