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CN-122010170-A - Lithium lanthanum zirconium oxide nano powder, preparation method thereof and application thereof in solid electrolyte

CN122010170ACN 122010170 ACN122010170 ACN 122010170ACN-122010170-A

Abstract

The invention belongs to the technical field of electrolyte materials, and provides lithium lanthanum zirconium oxide nano powder, a preparation method thereof and application thereof in solid electrolyte. According to the invention, zrO 2 、La 2 O 3 and water are mixed and dried, then melted at 1300-1600 ℃, quenched and crushed to obtain glass powder, then mixed with a Li source, and dried and calcined at 600-750 ℃ to obtain LLZO nano powder, so that not only is the particle size small, but also LLZO nano crystal grains are complete, and the crystal grains are not required to be crushed and refined again by virtue of post-treatment procedures such as ball milling or sand milling after calcination, thereby avoiding lattice distortion of the crystal grains, and the electrolyte sheet further prepared from the LLZO nano powder has the advantages of low calcination temperature, low Li volatilization and high ionic conductivity.

Inventors

  • XU WEI
  • DING JINDUO
  • GE CHUNQIAO
  • HUANG SHUTING

Assignees

  • 中山智隆新材料科技有限公司

Dates

Publication Date
20260512
Application Date
20260126

Claims (10)

  1. 1. The preparation method of the lithium lanthanum zirconium oxide nano powder is characterized by comprising the following steps of: (1) Mixing ZrO 2 、La 2 O 3 with water, and performing first drying to obtain first mixed powder; (2) Heating to 1300-1600 ℃, then, preserving heat for 1-5h at 1300-1600 ℃ for melting the first mixed powder, quenching after the melting is finished to obtain a glass precursor, and crushing to obtain glass powder; (3) And mixing the Li source with the glass powder to obtain a Li source mixture, performing second drying to obtain second mixed powder, and calcining at 600-750 ℃ to obtain the lithium lanthanum zirconium oxygen nano powder.
  2. 2. The method according to claim 1, wherein in the step (1), zrO 2 and La 2 O 3 are calculated and weighed according to Li 7-3x M x La 3 Zr 2 O 12 , wherein M is a doping metal and x=0 to 0.5.
  3. 3. The method of claim 1, further comprising mixing a dopant with ZrO 2 、La 2 O 3 and water in step (1), wherein the dopant is a metal-doped oxide, hydroxide or salt.
  4. 4. The method of claim 3, wherein in step (1), zrO 2 、La 2 O 3 , a dopant and water are mixed, a first organic acid is added, and/or in step (1), zrO 2 、La 2 O 3 , a dopant and water are mixed, and a first dispersant is added.
  5. 5. The method according to claim 4, wherein the first organic acid and the second organic acid are each independently selected from at least one of oxalic acid, citric acid, and malic acid.
  6. 6. The method according to claim 4, wherein the first dispersant and the second dispersant are each independently selected from at least one of polyvinylpyrrolidone, polyacrylamide, ammonium polymethacrylate, and polyethylene glycol.
  7. 7. The method of claim 1, wherein in step (2), the quenching is pouring into water.
  8. 8. The method according to claim 1, wherein in the step (2), dv50≤50 nm of the glass frit.
  9. 9. The method according to claim 1, wherein in the step (3), the calcination temperature is 650 to 700 ℃ and/or the calcination time is 3 to 10 hours.
  10. 10. The method of claim 1, wherein in step (3), the LLZO nano powder has a Dv50 of 200nm or less.

Description

Lithium lanthanum zirconium oxide nano powder, preparation method thereof and application thereof in solid electrolyte Technical Field The invention relates to the technical field of electrolyte materials, in particular to lithium lanthanum zirconium oxide nano powder, a preparation method thereof and application thereof in solid electrolyte. Background With the rapid development of electrochemical energy storage technology, the requirements on the safety and the energy density of a battery system are increasingly increased. Under the background, the solid electrolyte is becoming a key material for promoting the technical evolution of the battery due to the characteristics of incombustibility, high temperature resistance, good chemical stability and the like. Currently, solid-state electrolytes have shown broad application prospects in two major technical routes of semi-solid batteries and all-solid batteries. In semi-solid battery systems, solid electrolytes are introduced as functional additives or composite matrices for improving the intrinsic safety of the battery, inhibiting lithium dendrite growth, and enhancing electrode/electrolyte interface stability. In an all-solid-state battery system, the solid electrolyte completely replaces the traditional organic electrolyte and plays the dual roles of lithium ion transmission and physical separator. Among the numerous solid electrolyte materials, garnet-type Lithium Lanthanum Zirconium Oxide (LLZO) exhibits excellent comprehensive properties due to its unique crystal structure, namely that its cubic phase has abundant lithium ion vacancies, can achieve ionic conductivities of the order of up to 10 -3 S/cm, and a high electrochemical window enables it to match various high voltage cathode materials, while it has excellent stability to metallic lithium cathodes. However, LLZO powders are typically prepared using solid phase methods, and during and from which dense electrolyte sheets are further prepared, high temperature calcination (> 1000 ℃) is typically required to fully incorporate and maintain the cubic phase of each oxide, thereby achieving high ionic conductivity. However, li is extremely volatile at high temperatures (> 850 ℃) and increases progressively with increasing calcination temperature. Therefore, the impact of Li volatilization on LLZO synthesis and sintering is currently reduced mainly by adding an excess of 10-30wt% of Li source. However, the Li source is expensive, which greatly increases the manufacturing cost of LLZO, and limits its large-scale industrial application. In addition, in semi-solid batteries, solid electrolytes are often used for separator coating, cathode material mixing or coating, which places high demands on the particle size of the LLZO powder, which is typically required to be 300nm or less. However, the LLZO powder prepared by the conventional solid phase method has larger particles (usually, the particle size Dv50 is greater than 2 μm), and needs to be crushed and refined by ball milling or sand milling, etc., but the intense mechanical force can introduce a large number of crystal defects into the LLZO crystal lattice, and the defects can become scattering centers for lithium ion migration, reduce the ion conductivity of the electrolyte sheet prepared by the defects, and can become starting points for preferential growth of lithium dendrites. Therefore, there is a need to develop a preparation method of LLZO nano powder with low Li volatilization, and the LLZO nano powder prepared by the preparation method has the particle diameter Dv50 less than or equal to 200nm and can be further used for preparing electrolyte sheets with high ionic conductivity. Disclosure of Invention The present invention aims to solve at least one of the technical problems in the prior art described above. Therefore, the invention provides lithium lanthanum zirconium oxide nano powder, a preparation method thereof and application thereof in solid electrolyte. The LLZO nano powder provided by the invention has small particle size (Dv 50 particle size is 55-86 nm), LLZO nano crystal grains are complete, the crystal grains are not required to be crushed and refined by post-treatment procedures such as ball milling or sand milling after powder calcination, lattice distortion of the crystal grains is avoided, li volatilization is low, li loss is reduced, cost is reduced, and the ionic conductivity of an electrolyte sheet further prepared from the LLZO nano powder is high (for example, can reach (0.81-1.55) multiplied by 10 -3). The first aspect of the invention provides a preparation method of lithium lanthanum zirconium oxide nano powder. Specifically, the preparation method of the Lithium Lanthanum Zirconium Oxide (LLZO) nano powder comprises the following steps: (1) Mixing ZrO 2、La2O3 with water, and performing first drying to obtain first mixed powder; (2) Heating to 1300-1600 ℃, then, preserving heat for 1-5h at 1300-1600 ℃ for melting the fi