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CN-121983648-A - Solid electrolyte powder, low-temperature surface modification method and application

CN121983648ACN 121983648 ACN121983648 ACN 121983648ACN-121983648-A

Abstract

The invention discloses solid electrolyte powder, a low-temperature surface modification method and application thereof. The method comprises the steps of (1) forming a metal oxide seed layer on the surface of solid electrolyte powder through atomic layer deposition at the temperature of less than or equal to 140 ℃, 2) introducing a fluorine-containing precursor in a pulse mode at the temperature of 90-130 ℃ for carrying out fluoridation conversion, wherein the pulse times are 1-6 times, the single pulse is less than 10s and the interval is more than 60s, so that the seed layer is converted into an oxygen-fluorine co-doped surface layer, and (3) depositing a non-oxide final seal layer on the surface layer to obtain the modified solid electrolyte powder. The whole process of the method is less than or equal to 160 ℃, and the large-scale treatment can be realized. The surface of the obtained modified powder has no continuous inorganic oxide layer within 1nm, has F gradient distribution oxygen-fluorine co-doped surface layer and non-oxide final seal layer, and has the characteristics of electron blocking, chemical stability and lithium ion transmission. The lithium ion battery is suitable for halide and sulfide solid electrolyte powder, the air/wet heat stability and the electrode interface compatibility of the lithium ion battery are obviously improved, and the high capacity retention rate can be realized when the lithium ion battery is used for an all-solid lithium battery.

Inventors

  • XIE MING
  • ZHANG XUANXUAN
  • XIAO YI
  • WU XINBEI

Assignees

  • 柔电（武汉）科技有限公司

Dates

Publication Date
20260505
Application Date
20260114

Claims (14)

  1. 1. A modified solid electrolyte powder is characterized by comprising a non-oxide final seal layer, an M-O-F layer and a solid electrolyte powder from outside to inside in sequence; the non-oxide final sealing layer is selected from one of LiF, mgF 2 or LiPON; the M-O-F layer is a metal oxide layer or a metal organic film doped with metal fluoride, and the thickness of the metal oxide layer or the metal organic film in the M-O-F layer is lower than 0.5 nm; the solid electrolyte powder is a heat sensitive solid electrolyte material.
  2. 2. The modified solid electrolyte powder of claim 1 wherein the non-oxide final seal layer has a thickness of 1-6nm and an electronic conductance of the non-oxide final seal layer at 25 ℃ of 1x 10 -10 S•cm -1 or less and an in-plane lithium ion conductance of 1x 10 -7 S•cm -1 or more.
  3. 3. The modified solid electrolyte powder of claim 1, wherein the solid electrolyte powder particle size D 50 is 1-20 μιη.
  4. 4. The modified solid electrolyte powder of claim 1 wherein the M-O-F layer has a thickness of 0.3-1.5nm.
  5. 5. A low temperature surface modification method of a solid electrolyte powder for preparing the modified solid electrolyte powder according to any one of claims 1 to 4, comprising the steps of: (1) Depositing a low-temperature seed layer, namely depositing a seed layer with the thickness of 0.3-1.5 nm on the surface of the solid electrolyte powder through atomic layer deposition at the temperature of less than or equal to 140 ℃, wherein the seed layer can be a metal oxide layer or a metal organic film; (2) The low-temperature fluorination conversion treatment, namely, introducing a precursor of a target fluoride in a pulse mode at 90-130 ℃ to carry out fluorination conversion, so that the convertible seed layer is in situ converted into a metal oxide layer or a metal organic film doped with the metal fluoride, namely, an M-O-F layer with the thickness of 0.3-1.5 nm is formed on the surface layer and the subsurface layer of the solid electrolyte powder, and the thickness of the metal oxide layer or the metal organic film in the M-O-F layer is lower than 0.5 nm; (3) Depositing a non-oxide final seal layer, namely depositing the non-oxide final seal layer with the thickness of 1-6 nm on the surface of the powder treated in the step (2) under the condition of the temperature of less than or equal to 150 ℃ to obtain modified solid electrolyte powder; the metal organic film is a hybrid film formed by a metal center and an organic ligand, and a metal element M in the M-O-F layer is one of aluminum, magnesium, titanium, zirconium, yttrium and lanthanum.
  6. 6. The method of claim 5, wherein the step (1) seed layer deposition process comprises the steps of: s1, placing electrolyte powder into an ALD reaction cavity or placing the electrolyte powder into a porous container in the ALD reaction cavity, and then repeatedly vacuumizing to replace nitrogen for at least three times; S2, fluidizing the electrolyte powder in the reaction cavity under the atmosphere of nitrogen or argon, wherein the fluidizing pressure is 1-1000torr, or the electrolyte powder dispersing effect is achieved by rotating the porous container, and the fluidizing pressure is preferably 10-100torr; S3, selecting a reaction precursor according to the type of a deposited seed layer, and setting parameters of an ALD reaction chamber, wherein the deposition temperature is 100-140 ℃, and the deposition pressure is 0.01-500 torr; S4, introducing the precursor A steam into the ALD reaction cavity under the carrying of nitrogen or argon, wherein the holding time is 10-300 seconds, and the flow rate of the carried gas is 5-8000sccm; s5, purging the reaction cavity by using nitrogen or argon to take away the residual precursor A, wherein the flow rate of the carrier gas is 5-8000sccm; s6, introducing the precursor B into the ALD reaction cavity under the action of carrying gas, wherein the holding time is 10-300 seconds, and the flow rate of the carrying gas, namely nitrogen or argon, is 5-8000sccm; S7, purging the reaction cavity by using nitrogen or argon to take away excessive precursor B and byproducts; Repeating the steps S4 to S7 until the deposition of the seed layer corresponding to the precursor A reaches the set thickness of the coating of 0.3-1.5nm; When the seed layer is metal oxide, the precursor A is one or a mixture of more than 140 ℃ metal alkylamino salt, metal organic compound, halide, alkoxide and metal beta diketone complex, wherein the metal element in the metal alkylamino salt, metal organic compound, halide, alkoxide and metal beta diketone complex is one of aluminum, magnesium, titanium, zirconium, yttrium and lanthanum, and the precursor B is oxygen source steam; When the seed layer is a metal organic film, the precursor A is one or a mixture of more of metal alkylamino salt, metal organic compound, halide, alkoxide and metal beta diketone complex with the volatilization temperature not more than 140 ℃, wherein the metal element in the metal alkylamino salt, the metal organic compound, the halide, the alkoxide and the metal beta diketone complex is one of aluminum, magnesium, titanium, zirconium, yttrium and lanthanum, the precursor B is an organic ligand source with the volatilization temperature not more than 140 ℃, and the organic ligand source has two or more functional groups capable of reacting with metal hydroxyl/alkoxy, and the functional groups comprise-OH, -COOH and-NH 2 .
  7. 7. The method of claim 6, wherein the precursor a comprises TMA, mg (EtCp) 2 、TiCl 4 、Zr(NMe 2 ) 4 、Y(TMHD) 3 、La(TMHD) 3 .
  8. 8. The method of claim 5, wherein the step (2) of fluorinating comprises the steps of: H1. Placing solid electrolyte powder coated with a seed layer on the surface into an ALD reaction cavity or a porous container in the ALD reaction cavity, and then repeatedly vacuumizing to replace nitrogen for at least three times; H2. Fluidizing the solid electrolyte powder coated with the seed layer on the surface in the reaction cavity under the atmosphere of nitrogen or argon, wherein the fluidizing pressure is 1-1000torr, or the solid electrolyte powder coated with the seed layer on the surface is dispersed by rotating a porous container, and the fluidizing pressure is preferably 10-100torr; H3. setting parameters of an ALD reaction chamber, wherein the deposition temperature is 90-130 ℃ and the deposition pressure is 0.01-500 torr; H4. Introducing a precursor of the target fluoride into an ALD reaction cavity under the carrying of nitrogen or argon, and keeping 1-6 short gas phase pulses, wherein the flow rate of the carried gas is 5-8000sccm, and single pulse is <10s and interval is >60 s; H5. Purging the reaction cavity with nitrogen or argon to take away the residual precursor of the target fluoride, wherein the flow rate of the carrier gas is 5-8000sccm; H6. purging the reaction chamber with nitrogen or argon to take away excessive precursor and byproducts of the target fluoride, and converting part of the seed layer into metal fluoride, namely converting the metal oxide or the metal organic film into an M-O-F layer, wherein the M-O-F layer is a metal oxide layer or a metal organic film doped with the metal fluoride; The precursor of the target fluoride is HF-pyridine hydrogen fluoride pyridine C 5 H 6 FN or equivalent fluorine-containing precursor hydrogen fluoride triethylamine C 6 H 18 F 3 N, N, N-dimethyl prourea hydrogen fluoride complex C 6 H 13 FN 2 O.
  9. 9. The method of claim 5, wherein the non-oxide final seal layer deposition process of step (3) comprises the steps of: W1, placing the solid electrolyte powder treated in the step (2) into an ALD reaction cavity or a porous container in the ALD reaction cavity, and then repeatedly vacuumizing to replace nitrogen for at least three times; W2, fluidizing the solid electrolyte powder treated in the step (2) in a reaction cavity under the atmosphere of nitrogen or argon, wherein the fluidizing pressure is 1-1000torr, or the solid electrolyte powder treated in the step (2) is dispersed by rotating a porous container, and the fluidizing pressure is preferably 10-100torr; w3. setting parameters of an ALD reaction chamber, wherein the deposition temperature is 90-130 ℃, and the deposition pressure is 0.01-500 torr; w4. introducing a precursor C into an ALD reaction cavity under the carrying of nitrogen or argon for 10-300 seconds, wherein the flow rate of the carrying gas is 5-8000sccm; w5. purging the reaction chamber with nitrogen or argon to remove the residual precursor C, wherein the flow rate of the carrier gas is 5-8000sccm; w6. introducing the precursor D into the ALD reaction chamber under the action of a carrier gas, wherein the holding time is 10-300 seconds, and the flow rate of the carrier gas is 5-8000sccm; W7. purging the reaction chamber with nitrogen or argon to remove excess precursor D and byproducts; Repeating the steps W4 to W7 until the final seal layer deposition reaches the set coating thickness of 16nm; the non-oxide final sealing layer is one of LiF, mgF 2 or LiPON; the precursor C is one or a mixture of a plurality of metal alkylamino salts, metal organic compounds, halides, alkoxides and metal beta diketone complexes with the volatilization temperature not more than 150 ℃, wherein the metal elements in the metal alkylamino salts, the metal organic compounds, the halides, the alkoxides and the metal beta diketone complexes are lithium or magnesium; the precursor D is a precursor of a target fluoride or a phosphorus and nitrogen integrated precursor source.
  10. 10. The method of claim 9, wherein the precursor C comprises one or more of ：LiO t Bu、LiHMDS、Li(thd)、Li(hfac)、Li(Piv)(H 2 O)、Li(acac)、Li(CH 2 SiMe 3 )、Li( t Bu 2 Cp)、 bis (ethylcyclopentadienyl) magnesium, bis (2, 6-tetramethyl-3, 5-heptanedione) magnesium, bis (N, N' -bis (sec-butylacetamido) magnesium, bis (pentamethylcyclopentadienyl) magnesium.
  11. 11. The method of claim 9, wherein the precursor D comprises one or more of hexafluoroacetylacetone (Hhfac), carbonyl fluoride, chlorine fluoride, 1-chloro-2, 2-difluoroethylene, chlorodifluoromethane, 1-chloro-1-fluoroethane, difluoromethane, nitrogen trifluoride, pentafluoroethane, perfluorocyclohexene, trifluoroacetic acid, trifluoroethane, trifluoroethanol.
  12. 12. An all-solid-state lithium battery comprising a positive electrode, a negative electrode and a solid electrolyte layer therebetween, wherein the solid electrolyte layer is formed by densification of the modified solid electrolyte powder according to any one of claims 1 to 5 or the modified solid electrolyte powder prepared by the method according to any one of claims 6 to 11 or by compounding with a polymer.
  13. 13. The all-solid-state lithium battery according to claim 12, wherein the positive electrode material is one of a lithium-rich manganese-based material, a high-nickel ternary material, or a high-voltage spinel material, and the negative electrode material is lithium metal.
  14. 14. The all-solid-state lithium battery according to claim 12, wherein the polymer matrix is one of PEO, PVDF-HFP or polycarbonate, and the mass ratio of the electrolyte powder to the polymer matrix is 70:30 to 90:10.

Description

Solid electrolyte powder, low-temperature surface modification method and application Technical Field The invention relates to the technical field of surface modification of solid electrolyte materials, in particular to solid electrolyte powder, a low-temperature surface modification method and application. Background With the rapid development of electric vehicles and portable electronic devices, there is an increasing demand for high energy density, high safety batteries. All-solid-state lithium batteries are regarded as an important development direction of the next-generation battery technology because of their advantages of high safety, high energy density, long cycle life, and the like. In all-solid-state lithium batteries, solid-state electrolytes are a critical component, with sulfide and halide solid-state electrolytes having a high ionic conductivity having been of interest. Sulfide solid electrolyte (such as Li 6PS5Cl、Li6PS5 Br and the like) has excellent room temperature ion conductivity, but is extremely easy to decompose and release toxic H 2 S gas under an air/humidity environment, meanwhile, serious interface side reaction problems exist between the sulfide solid electrolyte and a lithium metal anode material, the sulfide solid electrolyte is reduced and decomposed by Li 0 with extremely low potential to generate S, li 3P、Li2S、Li2 X, non-conductive decomposition products are accumulated, interface resistance is increased, li+ transmission is hindered, unstable interfaces and uneven Li deposition can cause lithium dendrite formation and growth, electrolyte can be penetrated, short circuit of a battery is caused, active lithium and electrolyte are consumed by the interface side reaction, rapid decay of battery capacity and low coulomb efficiency are caused, and oxidation-reduction reaction between the sulfide electrolyte and a high-voltage anode material is generated, so that LPSC structure decomposition and capacity decay are caused. Although the halide solid electrolyte (such as Li 3InCl6、Li2ZrCl6 and the like) has higher oxidation stability, the halide solid electrolyte cannot avoid the problem of hydrolysis, low-conductivity materials such as LiCO 3, li 2 O and the like are easy to form on the surface, the problem of interface side reaction exists after the halide solid electrolyte contacts with lithium metal, lithium metal can reduce high-valence cations In the electrolyte, the reduction product comprises an alloy of Li and In/Y, the mixed conductivity property of the alloy phase cannot realize passivation protection on the interface, and the decomposition reaction can continuously occur. Surface modification and interfacial stability optimization of halide-based solid electrolytes at the powder scale remain challenges. To solve the stability problem of the solid electrolyte, the prior art generally adopts a method of forming a protective coating on the surface of the powder. CN108539250a discloses a method of forming a coating layer on the surface of a powder of a positive electrode material by Atomic Layer Deposition (ALD), and forming a solid electrolyte layer by high temperature sintering (300-1000 ℃). CN109244547B proposes that a metal oxide layer is coated on the surface of a solid electrolyte powder by ALD, and hot-pressed at 200-1400 ℃, and metal ions are doped into the solid electrolyte structure to prepare a composite solid electrolyte membrane. While these methods can improve material stability, higher process temperatures (200-300 ℃ or higher) are generally required, which may lead to phase changes, halogen volatilization or uncontrolled elemental diffusion for thermally sensitive solid state electrolyte materials. CN108172891B describes a method for preparing a positive electrode active material coated with a fluorinated modification layer by reacting a gaseous fluorine source with a positive electrode material in a closed container, which can avoid an interfacial reaction between the positive electrode material and a sulfur-based solid state electrolyte and reduce interfacial resistance. However, this method is mainly directed to surface modification of the cathode material, and the method does not perform surface conditioning on the solid electrolyte powder. The problem of interfacial side reactions still exists after the solid electrolyte powder is contacted with lithium metal. CN111129571a proposes a preparation method of an all-solid-state thin film lithium battery based on physical vapor deposition technology, and solves the problem of low ionic conductivity of the solid-state electrolyte thin film by selecting a solid-state electrolyte thin sheet with high ionic conductivity as a supporting structure. However, this technique is mainly suitable for thin film batteries, and is difficult to apply to large-scale processing of powdery solid electrolytes. In the prior art, although various surface modification methods are used for improving the stability of solid electrolyte