A precursor material for preparing lithium lanthanum zirconium oxide

Abstract

The invention discloses a precursor material for preparing lithium lanthanum zirconium oxide, the precursor material having a secondary spherical structure; the precursor material components include lanthanum (La), zirconium (Zr), oxygen (O) elements and doping elements, and the content of each element is as follows: lanthanum (La) element content is 50%-60%, zirconium (Zr) element content is 15%-25%, oxygen (O) element content is 20%-28%, and the content of doping elements is 0.5%-1%; the doping elements include one or more of aluminum, niobium, molybdenum, antimony, tantalum, and tungsten. The precursor material does not contain lithium element, which reduces the cost and loss of lithium raw materials in the process of synthesizing lithium lanthanum zirconium oxide material; pure phase lithium lanthanum zirconium oxide material can be prepared by the precursor material, with high repeatability; and the precursor material has a special secondary spherical structure.

Description

Technical Field

[0001] The present invention relates to the technical field of solid electrolyte materials, and in particular to a precursor material for preparing lithium lanthanum zirconium oxide. Background Art

[0002] At present, the lithium-ion batteries widely used in the market adopt liquid or gel electrolytes. The common characteristics of the two are the use of flammable and explosive organic matter and a certain fluidity, which brings serious safety hazards to the use of lithium-ion batteries.

[0003] Using solid electrolytes is one of the best solutions to solve safety hazards. Among the solid electrolyte materials reported so far, lithium lanthanum zirconium oxide with a cubic garnet structure is a material with great application prospects. Compared with other solid electrolyte materials, LLZO has very good thermal stability and electrochemical stability, and has advantages in battery cycle life and reliability.

[0004] Precursors are essential products for the preparation of lithium lanthanum zirconium oxide materials. The particle size, morphology, and structure of the precursors have a direct impact on the particle size, morphology, and structure of the subsequently processed lithium lanthanum zirconium oxide materials. The quality of the lithium lanthanum zirconium oxide material precursor directly determines the quality of the lithium lanthanum zirconium oxide. However, the lithium lanthanum zirconium oxide materials synthesized from the current lithium lanthanum zirconium oxide precursors have not achieved the goal of industrial production. For example, Chinese patent 201610323476.8 discloses a cubic phase lithium lanthanum zirconium oxide solid electrolyte nanomaterial. Therefore, it is of positive significance to develop a lithium lanthanum zirconium oxide precursor to realize the industrial production of lithium lanthanum zirconium oxide materials without damaging the comprehensive performance of lithium lanthanum zirconium oxide materials. Summary of the invention

[0005] The present invention is made to solve the above-mentioned problems, and its purpose is to provide a precursor material for preparing lithium lanthanum zirconium oxide.

[0006] In order to achieve the above purpose, the present invention adopts the following technical solutions:

[0007] The present invention provides a precursor material for preparing lithium lanthanum zirconium oxide, which is characterized in that: the precursor material has a secondary spherical structure; the components of the precursor material include lanthanum element (La), zirconium element (Zr), oxygen element (O) and doping element; the content of lanthanum element is 50%-60%; the content of zirconium element is 15%-25%; the content of oxygen element is 20%-28%; the content of doping element is 0.5%-1%; the doping element includes one or more of aluminum, niobium, molybdenum, antimony, tantalum and tungsten.

[0008] Furthermore, in a precursor material for preparing lithium lanthanum zirconium oxide provided by the present invention, it can also have the following characteristics: wherein the lanthanum element is derived from any one of lanthanum oxide, lanthanum nitrate, and lanthanum hydroxide.

[0009] Preferably, the lanthanum element is derived from lanthanum hydroxide.

[0010] Furthermore, in a precursor material for preparing lithium lanthanum zirconium oxide provided by the present invention, it can also have the following characteristics: wherein the zirconium element is derived from any one of zirconium oxide, zirconium nitrate and zirconium hydroxide.

[0011] Preferably, the zirconium element is derived from zirconium oxide.

[0012] Furthermore, in a precursor material for preparing lithium lanthanum zirconium oxide provided by the present invention, it can also have the following characteristics: wherein the average particle size of the primary particles in the secondary spherical structure is 100nm to 700nm, and the average particle size of the secondary particles is 1μm to 100μm.

[0013] Furthermore, in a precursor material for preparing lithium lanthanum zirconium oxide provided by the present invention, it can also have the following characteristics: the lanthanum element is lanthanum hydroxide, and the zirconium element is zirconium oxide; the lanthanum hydroxide and zirconium oxide are dispersed outside the secondary particles or in the gaps between the secondary particles.

[0014] Furthermore, in a precursor material for preparing lithium lanthanum zirconium oxide provided by the present invention, it can also have the following characteristics: wherein the doping elements are aluminum and tantalum; the aluminum element is derived from aluminum nitrate; and the tantalum element is derived from tantalum hydroxide.

[0015] Furthermore, in a precursor material for preparing lithium lanthanum zirconium oxide provided by the present invention, it can also have the following characteristics: wherein, the X-ray diffraction (XRD) pattern of the precursor material has a characteristic diffraction peak at a 2θ angle range of 26° to 31°.

[0016] Furthermore, in a precursor material for preparing lithium lanthanum zirconium oxide provided by the present invention, it can also have the following characteristics: wherein the precursor material is in the form of white powder.

[0017] Furthermore, in a precursor material for preparing lithium lanthanum zirconium oxide provided by the present invention, it can also have the following characteristics: wherein the particle size of the precursor material is 5μm-25μm.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] 1. The precursor provided by the present invention does not contain lithium element, which reduces the loss and waste of lithium raw materials; thereby reducing the cost and loss of lithium raw materials in the process of synthesizing lithium lanthanum zirconium oxide materials, and has the potential for large-scale industrial production.

[0020] 2. The precursor provided by the present invention has a special secondary spherical structure, and the spherical shape is conducive to the dispersion and sliding of the powder.

[0021] 3. The lithium lanthanum zirconium oxide material prepared by the precursor of the present invention has good phase homogeneity and high repeatability; the problem of instability in the preparation of lithium lanthanum zirconium oxide material caused by the loss or excess of lithium element is solved. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 is an X-ray diffraction (XRD) pattern of the precursor 1 in Example 1 of the present invention;

[0023] Figure 2 is an X-ray diffraction (XRD) pattern of the precursor 2 in Example 2 of the present invention;

[0024] Figure 3 is an X-ray diffraction (XRD) diagram of the lithium lanthanum zirconium oxide material prepared by the precursor of the present invention;

[0025] Figure 4 This is a scanning electron microscope (SEM) image of the precursor 1 in Example 1 of the present invention. DETAILED DESCRIPTION

[0026] In order to make the technical means, creative features, objectives and effects achieved by the present invention easy to understand, the following embodiments are combined with the accompanying drawings to specifically illustrate the technical solutions of the present invention.

[0027] <Example 1>

[0028] In Example 1, lanthanum hydroxide is used as the lanthanum source compound, and 12.314 g of lanthanum hydroxide is weighed. Zirconium oxide is used as the zirconium source compound, and 6.216 g of zirconium oxide is weighed. The dopants are aluminum nitrate and tantalum hydroxide, aluminum nitrate is used as the aluminum source, and tantalum hydroxide is used as the tantalum source. Aluminum nitrate provides trivalent aluminum, and tantalum hydroxide provides pentavalent tantalum. The dopant weighs 3 g. The oxygen element is provided by the aforementioned lanthanum hydroxide, zirconium oxide, aluminum nitrate, and tantalum hydroxide. The molar ratio of La and Zr is mixed in a ratio of 3:2. The above-mentioned lanthanum source compound, zirconium source compound, and dopant are directly mixed evenly without pretreatment, and then mixed and calcined to obtain a precursor 1.

[0029] The precursor 1 of this embodiment is a white powder material, and the particle size of the precursor 1 is 10μm. Its elemental composition and content are as follows: 54.25% lanthanum, 18.94% zirconium, and 26.81% oxygen; the added doping elements are aluminum and tantalum, with a total content of 0.5%. The precursor material is a composite material composed of lanthanum hydroxide, zirconium oxide, and compounds containing doping elements. Lanthanum-zirconium-oxygen-aluminum-tantalum in the composite are combined by chemical bonds rather than simple physical mixing, so it has high stability. Figure 1 The XRD diffraction pattern of the precursor 1 in this embodiment is shown in FIG. It can be seen that there is a characteristic diffraction peak at a 2θ angle range of 26° to 31°.

[0030] like Figure 4 As shown in FIG. , it is a scanning electron microscope (SEM) image of precursor 1. Figure 4 As shown in Figure (a), the precursor powder is fluffy and porous, with a unique secondary sphere appearance inside. The spherical shape is conducive to the dispersion and sliding of the powder. The particle size, morphology, and structure of the precursor have a direct impact on the particle size, morphology, and structure of the subsequently processed lithium lanthanum zirconium oxide material. The quality of the lithium lanthanum zirconium oxide material precursor directly determines the quality of the lithium lanthanum zirconium oxide. The characteristics of the unique secondary spherical structure of the precursor material also determine that the prepared lithium lanthanum zirconium oxide material powder has the same characteristics. The prior art has proven that spherical lithium lanthanum zirconium oxide has good electrical conductivity and dispersibility characteristics, which will not be elaborated here. Figure 4 As shown in (b), through microscopic morphology observation, the average particle size of the primary particles in the secondary spherical structure is 450nm, and the average particle size of the secondary particles is 5μm; lanthanum hydroxide and zirconium oxide are dispersed and arranged outside the secondary particles or in the gaps between the secondary particles.

[0031] <Example 2>

[0032] In Example 1, lanthanum hydroxide is used as the lanthanum source compound, and 81.217 g of lanthanum hydroxide is weighed. Zirconium nitrate is used as the zirconium source compound, and 42.162 g of zirconium nitrate is weighed. The dopants are aluminum nitrate and tantalum hydroxide, and the dopants weigh 6 g. The oxygen element is provided by the aforementioned lanthanum hydroxide, zirconium nitrate, aluminum nitrate, and tantalum hydroxide. The molar ratio of La and Zr is mixed in a ratio of 3:2. The above-mentioned lanthanum source compound, zirconium source compound, and dopant are directly mixed evenly without pretreatment, and then mixed and calcined to obtain precursor 2.

[0033] The precursor 2 of this embodiment is a white powder, and the particle size of the precursor material is 8 μm. Its element composition and content are as follows: 58.86% lanthanum, 24.40% zirconium, and 21.74% oxygen. Figure 2The figure shows the XRD diffraction pattern of the precursor material. It can be seen that there is a characteristic diffraction peak at a 2θ angle range of 26° to 31°. Figure 2 It can be seen that the precursor 2 prepared in this example has the same physical phase as the precursor 1 prepared in Example 1, both of which are pure cubic phases. This shows that the precursor provided by the present invention has good reproducibility.

[0034] <Example 3>

[0035] Example 3 Preparation of lithium lanthanum zirconium oxide material:

[0036] The lithium lanthanum zirconium oxide material was prepared by using the precursor 1 in Example 1 and the precursor 2 in Example 2, and the crystal structure of the prepared lithium lanthanum zirconium oxide material powder was characterized by X-ray diffraction. Figure 3 As shown, Figure 3 (a) is the lithium lanthanum zirconium oxide material prepared by the precursor 1 in Example 1; Figure 3 (b) is the lithium lanthanum zirconium oxide material prepared from the precursor 2 in Example 2. Figure 3 It can be seen that the crystal forms of the lithium lanthanum zirconium oxide materials prepared by precursor 1 and precursor 2 conform to the standard card JCPDS NO.40-0894, which indicates that: 1) the lithium lanthanum zirconium oxide material can be successfully prepared by the precursor material of the present invention; 2) the lithium lanthanum zirconium oxide material prepared by the precursor material has high crystallinity and purity; 3) the lithium lanthanum zirconium oxide material prepared by the precursor material provided by the present invention has high repeatability.

[0037] In summary, the present invention provides a precursor material for preparing lithium lanthanum zirconium oxide, which does not contain lithium element, saves production cost and avoids waste of lithium raw materials; the precursor material has a special secondary spherical structure; high-purity cubic phase lithium lanthanum zirconium oxide material can be successfully prepared by the precursor material, which has the potential to realize the industrial production and large-scale application of lithium lanthanum zirconium oxide material.

[0038] The above embodiments are only specific implementation methods of the present invention and are not intended to limit the protection scope of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A precursor material for preparing lithium lanthanum zirconium oxide, Features: The precursor material comprises lanthanum, zirconium, oxygen and doping elements; The content of the lanthanum element is 50%-60%; The content of zirconium element is 15%-25%; The content of the oxygen element is 20%-28%; The content of the doping element is 0.5%-1%; The doping elements are aluminum and tantalum, the aluminum element is derived from the dopant aluminum nitrate, and the tantalum element is derived from the dopant tantalum hydroxide; The lanthanum element is lanthanum hydroxide, the zirconium element is zirconium oxide, and the lanthanum hydroxide and the zirconium oxide are mixed in a ratio of La to Zr of 3:2; The lanthanum source compound, the zirconium source compound and the dopant are directly mixed evenly without pretreatment, and then mixed and calcined to obtain a precursor, wherein the precursor material is a composite material composed of lanthanum hydroxide, zirconium oxide and a compound containing a doping element, wherein lanthanum-zirconium-oxygen-aluminum-tantalum in the composite material is bonded by chemical bonds; The X-ray diffraction XRD pattern of the precursor material has a characteristic diffraction peak at a 2θ angle range of 26° to 31°, the particle size of the precursor material is 5μm-25μm, and the precursor material has a secondary spherical structure, wherein the average particle size of the primary particles is 450nm, the average particle size of the secondary particles is 5μm, and lanthanum hydroxide and zirconium oxide are dispersed and arranged outside the secondary particles or in the gaps between the secondary particles.

2. The precursor material for preparing lithium lanthanum zirconium oxide according to claim 1, characterized in that: in, The precursor material is in the form of white powder.

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