CN113889662B - Halide solid electrolyte material and preparation method and application thereof - Google Patents

Abstract

The invention relates to the technical field of lithium ion batteries, in particular to a halide solid electrolyte material and a preparation method and application thereof. The chemical general formula of the halide solid electrolyte material provided by the invention is LiaA _1‑x‑y M _x N _y X _3+a‑x+y Wherein a is more than or equal to 1 and less than or equal to 6; x is more than or equal to 0.02 and less than or equal to 0.9; y is more than or equal to 0.02 and less than or equal to 0.9; a is selected from Al ³⁺ 、Ga ³⁺ 、In ³⁺ 、Fe ³⁺ 、Y ³⁺ 、Sc ³⁺ One or more kinds of metals having a valence of +3 La; m is selected from Cu ²⁺ 、Zn ²⁺ 、Cd ²⁺ 、Mg ²⁺ 、Ca ²⁺ 、Sr ²⁺ 、Ba ²⁺ One or more of (a); n is selected from Zr ⁴⁺ 、Hf ⁴⁺ 、Ti ⁴⁺ One or more of (a); x is selected from F ^‑ 、Cl ^‑ 、Br ^‑ 、I ^‑ One or more of (a). The halide solid electrolyte material provided by the invention can obviously reduce the diffusion impedance of lithium ions in the electrolyte material, improve the shuttle capability and transmission speed of the lithium ions in the electrolyte lattice, and improve the conductivity of the lithium ions.

Description

A kind of halide solid electrolyte material and its preparation method and application

technical field

The invention relates to the technical field of lithium ion batteries, in particular to a halide solid electrolyte material and a preparation method and application thereof.

Background technique

Since the introduction of lithium-ion batteries, they have been widely used in various portable electronic products and electric vehicles. However, the recent frequent occurrence of new energy vehicle safety accidents is mainly due to the fact that traditional lithium-ion batteries need to use flammable organic solvents as electrolytes, so there are great safety hazards, which cannot be completely solved by usual improvement methods. In comparison, solid-state lithium-ion batteries using solid-state electrolytes have a safety advantage. The use of solid-state electrolytes can not only fundamentally solve the safety problem of lithium-ion batteries, but also is expected to greatly simplify the manufacturing and packaging process, and improve the energy density, reliability and design freedom of batteries. Among all kinds of new battery systems, solid-state batteries are the next-generation technology closest to industrialization. In order to meet the needs of high-performance solid-state batteries, electrolytes with high ionic conductivity are extremely critical materials.

At present, the inorganic electrolyte with the highest ionic conductivity is the sulfide system, which can reach or even exceed the level of the current commercial electrolyte in terms of ionic conductivity. However, the cost of raw materials for sulfide is high, the preparation conditions are harsh, and it cannot be stably matched with lithium metal negative electrodes or high-voltage positive electrodes, and battery assembly needs to be carried out in an expensive dry room to avoid decomposition caused by contact with water and oxygen in the air. Compared with sulfide, oxide electrolytes represented by lithium lanthanum zirconium oxide (LLZO) can match high-voltage positive electrodes and lithium metal negative electrodes, but the interface contact resistance of positive and negative electrodes is relatively large, and it needs to be prepared under harsh conditions of high temperature and high pressure. In order to achieve its high ionic conductivity (>1mS/cm). The halide Li ₃ AX ₆ (X is Cl or Br) is a class of solid electrolyte materials that has recently attracted attention, with many advantages such as high ionic conductivity and good compatibility with cathode materials. However, the Li ₃ AX ₆ phase structure, ionic conductivity, and metal negative electrode stability are affected by the type and radius of the metal ion A. In order to maintain structural stability and high ionic conductivity, A is mainly selected from the ionic radius between 0.65-0.92. The inter-trivalent metal ions mainly include In ³⁺ and rare earth ions. The content of these elements in the earth's crust is relatively small and expensive, and the mutual substitution between trivalent ions is difficult to effectively adjust the ratio of lithium ions/holes and improve the quality of lithium ions. Ion diffusion channels and enhanced ionic conductivity.

Contents of the invention

The purpose of the present invention is to overcome the defects of the existing halide solid electrolyte materials such as high cost, high diffusion resistance in the electrolyte material, and limited lithium ion conductivity, and further provide a halide solid electrolyte material and its preparation method and application .

To achieve the above object, the present invention adopts the following technical solutions:

A halide solid electrolyte material, the general chemical formula of the electrolyte material is LiaA _1-xy M _x N _y X _3+a-x+y , wherein 1≤a≤6; 0.02≤x≤0.9; 0.02≤y ≤0.9; A is selected from one or more of Al ³⁺ , Ga ³⁺ , In ³⁺ , Fe ³⁺ , Y ³⁺ , Sc ³⁺ , and +3-valent La metals; M is selected from Cu ²⁺ , Zn ²⁺ , Cd ²⁺ , Mg ²⁺ , Ca ²⁺ , Sr ²⁺ , Ba ²⁺ one or more; N is selected from one of Zr ^{4 +} , Hf ⁴⁺ , Ti ⁴⁺ or more; X is selected from one or more of F ^- , Cl ^- , Br ^- , I ^- .

It can be understood that the metal element represented by A in the general chemical formula can be one or more of Al, Ga, In, Fe, Y, Sc and La series elements; the metal element represented by M can be Cu, Zn, One or more of Cd, Mg, Ca, Sr and Ba; the metal element represented by N can be one or more of Zr, Hf and Ti; X represents one of F, Cl, Br and I or more. It can be understood that the metal represented by A has a valence of +3 in the general chemical formula, the metal represented by M has a valence of +2 in the general chemical formula, the metal represented by N has a valence of +4 in the general chemical formula, and the halogen represented by X Elements have a valence of -1 in the general chemical formula. The La series metals of the present invention include but are not limited to La (lanthanum), Ce (cerium), Pr (praseodymium), Nd (neodymium), Pm (promethium), Sm (samarium), Eu (europium), Gd (gadolinium), Tb (terbium), Dy (dysprosium), Ho (holmium), Er (erbium), Tm (thulium), Yb (ytterbium), Lu (lutetium).

Preferably, A is selected from one or more of Ga ³⁺ , In ³⁺ , Fe ³⁺ , Y ³⁺ , Sc ³⁺ , Ho ³⁺ , Er ³⁺ , Lu ³⁺ , and Yb ³⁺ ; and /or, M is selected from one or more of Mg ²⁺ , Zn ²⁺ , Cu ²⁺ ; and/or, N is selected from Zr ⁴⁺ and/or Hf ⁴⁺ ;

And/or, 2.2≤a≤3.8; and/or, 0.1≤x≤0.5; and/or, 0.1≤y≤0.7.

Preferably, A is selected from Fe ³⁺ , and N is selected from Hf ⁴⁺ .

Preferably, the halide solid electrolyte material is in any form of glass phase, glass-ceramic phase or crystal phase.

The present invention also provides a method for preparing the above-mentioned halide solid electrolyte material, comprising the following steps:

1) mixing the raw materials in the formula ratio to obtain the mixture;

2) Grinding and sintering the mixture to obtain the halide solid electrolyte material.

In the present invention, any method of ball milling, solid phase sintering, and heating eutectic can be used to prepare the halide solid electrolyte material for the mixture. Preferably, the mixture is prepared by grinding and sintering.

The ion conductivity of the halide solid electrolyte material prepared by the invention is greater than 1×10 ^-5 S/cm.

Preferably, the mixture is ground by ball milling in step 2), the ball milling speed is 100-500 rpm, and the ball milling time is 1-50h; preferably, the ball milling speed is 200-450 rpm, and the ball milling time is 2 -40h.

The grinding step is carried out under an inert atmosphere;

The sintering temperature is 200-600°C, and the holding time is 1-40h. Preferably, the sintering temperature is 250-550°C, and the holding time is 2-30h.

Optionally, the heating rate during the sintering step may be 1-3° C./min, and the cooling rate may be 1-3° C./min after the heat preservation is completed.

Preferably, after the sintering in step 2), a step of grinding the sintered material is also included.

Preferably, in step 1), an agate mortar can be used to mix the raw materials, so that the raw materials can be mixed evenly. Optionally, the material weighing step and mixing step in the present invention are all carried out under an inert gas atmosphere.

preferred,

The raw materials described in step 1) are lithium source, A source, M source and N source, wherein the lithium source is lithium halide, and the A source is selected from Al halide, Ga halide, In halide, Fe halide , one or more of halides of Y, halides of Sc and halides of La-series metals;

The M source is selected from one or more of Cu halides, Zn halides, Cd halides, Mg halides, Ca halides, Sr halides and Ba halides;

The N source is selected from one or more of Zr halides, Hf halides and Ti halides. It can be understood that the aforementioned metal halides include metal iodides, metal bromides, metal chlorides and metal fluorides. Taking metal chloride as an example, the lithium source is lithium chloride, and the A source is selected from the chlorides of aluminum chloride, gallium chloride, indium chloride, ferric chloride, yttrium chloride, scandium chloride and La series metals one or more of

The M source is selected from one or more of copper chloride, zinc chloride, cadmium chloride, magnesium chloride, calcium chloride, strontium chloride and barium chloride;

The N source is selected from one or more of zirconium chloride, hafnium chloride and titanium chloride.

The present invention also provides a lithium secondary battery, comprising a positive electrode layer, an electrolyte layer and a negative electrode layer, at least one of the positive electrode layer, the electrolyte layer and the negative electrode layer contains the above-mentioned halide solid electrolyte material or the above-mentioned Preparation method The prepared halide solid electrolyte material.

Preferably, the lithium secondary battery includes a liquid phase lithium secondary battery, a semi-solid lithium secondary battery and an all-solid lithium secondary battery.

Beneficial effects of the present invention:

1. The halide solid-state electrolyte material provided by the present invention introduces specific divalent and tetravalent ions into the electrolyte components at the same time, and utilizes the valence difference between divalent ions and tetravalent ions and trivalent ions. Divalent ions Substitution of trivalent ions with tetravalent ions will cause changes in the number of lithium ions and holes in the lattice (substitution process: M ²⁺ +Li ⁺ →A ³⁺ + holes; N ⁴⁺ + holes →A ³⁺ + Li ⁺ ), specifically, the replacement of trivalent ions by divalent ions will increase lithium ions and reduce holes, while the replacement of trivalent ions by tetravalent ions will increase holes and reduce lithium ions. Through the interaction and coordination of the two sides, it can Flexible and effective adjustment of the ratio of lithium ions/holes; in addition, by introducing divalent ions and tetravalent ions into the trivalent ion site at the same time, divalent ions, tetravalent ions, and trivalent ions are mixed and arranged in the crystal lattice to generate an electron cloud The local differentiation of the arrangement, this potential difference will form a driving force for the diffusion of lithium ions, and then promote the rapid shuttling of lithium ions between lattices. The combined effect of the above two aspects can significantly reduce the diffusion resistance of lithium ions in the electrolyte material, improve the shuttle ability and transmission speed of lithium ions inside the electrolyte lattice, improve the conductivity of lithium ions, and then improve the rate performance and fast charge of the battery. ability. At the same time, the use of scarce and expensive trivalent ions is reduced, thereby reducing the raw material cost of the electrolyte material and enhancing its practical application value.

2. The halide solid electrolyte material provided by the present invention, further, A is selected from Ga ³⁺ , In ³⁺ , Fe ³⁺ , Y ³⁺ , Sc ³⁺ , Ho ³⁺ , Er ³⁺ , Lu ^{3+ ,} One or more of Yb ³⁺ ; M is selected from one or more of Mg ²⁺ , Zn ²⁺ , Cu ²⁺ ; N is selected from Zr ⁴⁺ and/or Hf ⁴⁺ ; 2.2≤a≤ 3.8; 0.1≤x≤0.5; 0.1≤y≤0.7. In the present invention, by further limiting the element types of metals A, M, and N, the ion conductivity of the material can be further improved.

3. The halide solid-state electrolyte material provided by the present invention, further, A is selected from Fe ³⁺ , and N is selected from Hf ⁴⁺ . The present invention can significantly improve the material by limiting specific A and N elements and interacting with other elements. ionic conductivity.

Detailed ways

The following examples are provided in order to further understand the present invention better, are not limited to the best implementation mode, and do not limit the content and protection scope of the present invention, anyone under the inspiration of the present invention or use the present invention Any product identical or similar to the present invention obtained by combining features of other prior art falls within the protection scope of the present invention.

If no specific experimental steps or conditions are indicated in the examples, it can be carried out according to the operation or conditions of the conventional experimental steps described in the literature in this field. The reagents or instruments used, whose manufacturers are not indicated, are all commercially available conventional reagent products.

Example 1

This embodiment provides a method for preparing a halide solid electrolyte material, comprising the following steps:

1) Under the protection of an argon atmosphere, weigh 3.425 grams of LiCl, 1.404 grams of FeCl ₃ , 0.549 grams of MgCl ₂ , and 4.621 grams of HfCl ₄ ; put the above materials in an agate mortar and grind for 10 minutes to obtain a mixture;

2) Pour the mixture into a 100mL ball mill tank with a ball-to-material ratio of 20:1. After sealing, use a planetary ball mill for ball milling. The ball milling speed is 400 rpm, and the ball milling time is 20 hours. Under protection, open the ball mill tank and scrape out the material, use a tablet press to press the ball milled material into 12mm pieces, put it into a single-head quartz tube, then seal it with vacuum sealing and place it in a muffle furnace at high temperature Sintering, the sintering temperature is 450°C, and the holding time is 6h. After the holding is over, cool to room temperature, then put the quartz tube into the glove box and open it, and grind the obtained material with an agate mortar for 30 minutes to obtain the glass-ceramic Phase halide solid electrolyte material Li _2.8 Fe _0.3 Mg _0.2 Hf _0.5 Cl _6.1 .

Example 2

This embodiment provides a method for preparing a halide solid electrolyte material, comprising the following steps:

1) Under the protection of an argon atmosphere, weigh 2.546 grams of LiCl, 0.961 grams of GaCl ₃ , 0.372 grams of ZnCl ₂ , and 6.121 grams of HfCl ₄ ; put the above materials in an agate mortar and grind for 10 minutes to obtain a mixture;

2) Pour the mixture into a 100mL ball mill tank with a ball-to-material ratio of 20:1. After sealing, use a planetary ball mill for ball milling. The ball milling speed is 500 rpm, and the ball milling time is 1 hour. Under protection, open the ball mill tank and scrape out the material, use a tablet press to press the ball milled material into 12mm pieces, put it into a single-head quartz tube, then seal it with vacuum sealing and place it in a muffle furnace at high temperature Sintering, the sintering temperature is 200°C, and the holding time is 1h. After the holding, cool to room temperature, then put the quartz tube into the glove box and open it, and grind the obtained material with an agate mortar for 30 minutes to obtain the glass-ceramic Phase halide solid electrolyte material Li _2.2 Ga _0.2 Zn _0.1 Hf _0.7 Cl _5.8 .

Example 3

This embodiment provides a method for preparing a halide solid electrolyte material, comprising the following steps:

1) Under the protection of an argon atmosphere, weigh 3.192 grams of LiCl, 2.100 grams of YCl ₃ , 2.410 grams of CuCl ₂ , and 2.297 grams of HfCl ₄ ; put the above materials in an agate mortar and grind for 10 minutes to obtain a mixture;

2) Pour the mixture into a 100mL ball mill tank with a ball-to-material ratio of 20:1. After sealing, use a planetary ball mill for ball milling. The ball milling speed is 100 rpm, and the ball milling time is 50 hours. Under protection, open the ball mill tank and scrape out the material, use a tablet press to press the ball milled material into 12mm pieces, put it into a single-head quartz tube, then seal it with vacuum sealing and place it in a muffle furnace at high temperature Sintering, the sintering temperature is 600°C, and the holding time is 40h. After the holding time, cool to room temperature, then put the quartz tube into the glove box and open it, and grind the obtained material with an agate mortar for 30 minutes to obtain the glass-ceramic Phase halide solid electrolyte material Li _2.1 Y _0.3 Cu _0.5 Hf _0.2 Cl _4.8 .

Example 4

This example provides a method for preparing a halide solid-state electrolyte material. Compared with Example 1, the only difference is that in step 1) under the protection of an argon atmosphere, 3.865 grams of LiCl, 1.972 grams of FeCl ₃ , and 1.243 grams of ZnCl were weighed. _2. 2.920 grams of HfCl ₄ ; the above materials were ground in an agate mortar for 10 minutes to obtain a mixture. The halide solid electrolyte material prepared in this example is a glass-ceramic phase with a general chemical formula of Li ₃ Fe _0.4 Zn _0.3 Hf _0.3 Cl ₆ .

Example 5

This example provides a method for preparing a halide solid-state electrolyte material. Compared with Example 1, the only difference is that in step 1) under the protection of an argon atmosphere, 0.715 grams of LiCl, 1.824 grams of ScCl ₃ , and 0.821 grams of ZnCl were weighed. _2. 1.930 grams of HfCl ₄ , and 4.710 grams of LiBr; the above materials were ground in an agate mortar for 10 minutes to obtain a mixture. The halide solid electrolyte material prepared in this example is a glass-ceramic phase, and its general chemical formula is Li _2.95 Sc _0.5 Zn _0.25 Hf _0.25 Cl _3.7 Br _2.25 .

Example 6

This example provides a method for preparing a halide solid-state electrolyte material. The difference between it and Example 1 is that in step 1) under the protection of an argon atmosphere, 3.224 grams of LiCl, 2.261 grams of YbCl ₃ , and 1.078 grams of MgCl were weighed. _2. 3.017 grams of ZrCl ₄ , and 0.420 grams of LiF; the above materials were ground in an agate mortar for 10 minutes to obtain a mixture. The halide solid electrolyte material prepared in this example is a glass-ceramic phase with a general chemical formula of Li _2.85 Yb _0.25 Mg _0.35 Zr _0.4 F _0.5 Cl _5.4 .

Example 7

This example provides a method for preparing a halide solid electrolyte material. Compared with Example 1, the only difference is that in step 1) under the protection of an argon atmosphere, 3.537 grams of LuCl ₃ , 0.571 grams of ZnCl ₂ , and 1.342 grams of ZnCl 2 were weighed. HfCl ₄ , 4.549 grams of LiBr; the above materials were placed in an agate mortar and ground for 10 minutes to obtain a mixture. The halide solid electrolyte material prepared in this example is a glass-ceramic phase, and its general chemical formula is Li _2.5 Lu _0.6 Zn _0.2 Hf _0.2 Cl ₃ Br _2.5 .

Example 8

This example provides a method for preparing a halide solid electrolyte material, which differs from Example 1 only in that in step 1) under the protection of an argon atmosphere, 0.447 grams of LiCl, 1.499 grams of HoCl ₃ , and 0.813 grams of HoBr were weighed. _3. 0.203 grams of CuCl ₂ , 3.003 grams of HfBr ₄ and 4.034 grams of LiI; the above materials were ground in an agate mortar for 10 minutes to obtain a mixture. The halide solid electrolyte material prepared in this example is a glass-ceramic phase with a general chemical formula of Li _2.7 Ho _0.5 Cu _0.1 Hf _0.4 Cl ₂ Br ₂ I ₂ .

Example 9

This example provides a method for preparing a halide solid electrolyte material, which differs from Example 1 only in that in step 1) under the protection of an argon atmosphere, 2.073 grams of LiCl, 2.509 grams of ErBr ₃ , and 1.250 grams of ZnCl are weighed. _2. 1.514 grams of TiF ₄ and 2.654 grams of LiBr; the above materials were ground in an agate mortar for 10 minutes to obtain a mixture. The halide solid electrolyte material prepared in this example is a glass-ceramic phase, and its general chemical formula is Li _2.6 Er _0.3 Zn _0.3 Ti _0.4 F _1.6 Cl _3.1 Br.

Example 10

This example provides a method for preparing a halide solid-state electrolyte material. Compared with Example 1, the only difference is that in step 1) under the protection of an argon atmosphere, 1.600 grams of LiCl, 5.217 grams of LuBr ₃ , and 0.233 grams of CaCl were weighed. _2. 0.332 grams of SrCl ₂ , 1.343 grams of HfCl ₄ and 1.275 grams of LiBr; the above materials were ground in an agate mortar for 10 minutes to obtain a mixture. The halide solid electrolyte material prepared in this example is a glass-ceramic phase with a general chemical formula of Li _2.5 Lu _0.6 Ca _0.1 Sr _{0. 1} Hf _0.2 Cl ₃ Br _2.5 .

Example 11

This example provides a method for preparing a halide solid electrolyte material, which differs from Example 1 only in that in step 1) under the protection of an argon atmosphere, 0.693 grams of LiCl, 2.544 grams of LuBr ₃ , and 1.124 grams of CdCl were weighed. _2. 2.620 grams of HfCl ₄ and 3.019 grams of LiBr; the above materials were placed in an agate mortar and ground for 10 minutes to obtain a mixture. The halide solid electrolyte material prepared in this example is a glass-ceramic phase, and its general chemical formula is Li _2.5 Lu _0.3 Cd _0.3 Hf _0.4 Cl ₃ Br _2.6 .

Example 12

This example provides a method for preparing a halide solid-state electrolyte material. Compared with Example 1, the only difference is that in step 1) under the protection of an argon atmosphere, 3.162 grams of LiCl, 3.806 grams of InCl ₃ , and 1.195 grams of BaCl were weighed. ₂ and 1.837 g of HfCl ₄ ; the above materials were ground in an agate mortar for 10 min to obtain a mixture. The halide solid electrolyte material prepared in this example is a glass-ceramic phase with a general chemical formula of Li _2.6 In _0.6 Ba _0.2 Hf _0.2 Cl _5.6 .

Example 13

This example provides a method for preparing a halide solid-state electrolyte material. Compared with Example 1, the only difference is that in step 1) under the protection of an argon atmosphere, 6.041 grams of LiCl, 2.875 grams of ScCl ₃ , and 0.324 grams of ZnCl were weighed. ₂ and 0.761 g of HfCl ₄ ; the above materials were placed in an agate mortar and ground for 10 min to obtain a mixture. The halide solid electrolyte material prepared in this example is a glass-ceramic phase, and its general chemical formula is Li ₆ Sc _0.8 Zn _0.1 Hf _0.1 Cl ₉ .

Example 14

This example provides a method for preparing a halide solid-state electrolyte material. Compared with Example 1, the only difference is that in step 1) under the protection of an argon atmosphere, 1.499 grams of LiCl, 4.344 grams of InCl ₃ , and 1.071 grams of ZnCl were weighed. _2. 2.746 grams of ZrCl ₄ and 0.341 grams of LiBr; the above materials were placed in an agate mortar and ground for 10 minutes to obtain a mixture. The halide solid electrolyte material prepared in this example is a glass-ceramic phase, and its general chemical formula is LiIn _0.5 Zn _0.2 Zr _0.3 Cl ₄ Br _0.1 .

Example 15

This example provides a method for preparing a halide solid-state electrolyte material. Compared with Example 1, the only difference is that in step 1) under the protection of an argon atmosphere, 3.441 grams of LiCl, 3.590 grams of InCl ₃ , and 0.369 grams of ZnCl were weighed. ₂ and 2.600 g of HfCl ₄ ; the above materials were ground in an agate mortar for 10 min to obtain a mixture. The halide solid electrolyte material prepared in this example is a glass-ceramic phase with a general chemical formula of Li ₃ In _0.6 Zn _0.1 Hf _0.3 Cl _6.2 .

Example 16

This example provides a method for preparing a halide solid-state electrolyte material. Compared with Example 1, the only difference is that in step 1) under the protection of an argon atmosphere, 4.255 grams of LiCl, 2.337 grams of ScCl ₃ , and 1.838 grams of MgCl were weighed. _2. 0.900 g of ZrCl ₄ and 0.671 g of LiBr; the above materials were ground in an agate mortar for 10 min to obtain a mixture. The halide solid electrolyte material prepared in this example is a glass-ceramic phase with a general chemical formula of Li _2.8 Sc _0.4 Mg _0.5 Zr _0.1 Cl _5.2 Br _0.2 .

Example 17

This example provides a method for preparing a halide solid electrolyte material, which differs from Example 1 only in that in step 1) under the protection of an argon atmosphere, 3.199 grams of LiCl, 0.266 grams of GaCl ₃ , and 0.206 grams of ZnCl are weighed. ₂ and 6.330 g of ZrCl ₄ ; the above materials were ground in an agate mortar for 10 min to obtain a mixture. The halide solid electrolyte material prepared in this example is a glass-ceramic phase with a general chemical formula of Li _2.5 Ga _0.05 Zn _0.05 Zr _0.9 Cl _6.35 .

Example 18

This example provides a method for preparing a halide solid-state electrolyte material. Compared with Example 1, the only difference is that in step 1) under the protection of an argon atmosphere, 2.368 grams of LiCl, 0.650 grams of ErCl ₃ , and 3.644 grams of ZnCl were weighed. _2. 0.190 g of HfCl ₄ and 3.147 g of LiBr; the above materials were ground in an agate mortar for 10 min to obtain a mixture. The halide solid electrolyte material prepared in this example is a glass-ceramic phase with a general chemical formula of Li _3.1 Er _0.08 Zn _0.9 Hf _0.02 Cl ₄ Br _1.22 .

Example 19

This example provides a method for preparing a halide solid-state electrolyte material. Compared with Example 1, the only difference is that in step 1) under the protection of an argon atmosphere, 3.897 grams of LiCl, 1.992 grams of LaCl ₃ , and 1.083 grams of MgCl were weighed. _2. 3.028 grams of ZrCl ₄ ; the above materials were ground in an agate mortar for 10 minutes to obtain a mixture. The halide solid electrolyte material prepared in this example is a glass-ceramic phase with a general chemical formula of Li _2.83 La _0.25 Mg _0.35 Zr _0.4 Cl _5.88 .

Example 20

This example provides a method for preparing a halide solid electrolyte material, which differs from Example 1 only in that in step 1) under the protection of an argon atmosphere, 2.113 grams of LiCl, 3.942 grams of GdCl ₃ , and 0.680 grams of ZnCl are weighed. _2. 1.597 grams of HfCl ₄ and 1.668 grams of LiI; the above materials were placed in an agate mortar and ground for 10 minutes to obtain a mixture. The halide solid electrolyte material prepared in this example is a glass-ceramic phase, and its general chemical formula is Li _2.5 Gd _0.6 Zn _0.2 Hf _0.2 Cl ₅ I _0.5 .

Comparative example 1

This comparative example provides a kind of preparation method of halide solid electrolyte material, and its difference compared with embodiment 1 is that in step 1) under the protection of argon atmosphere, weigh 3.944 grams of LiCl and 6.056 grams of YCl ₃ ; Place in an agate mortar and grind for 10 minutes to obtain a mixture. The halide solid electrolyte material prepared in this comparative example is a glass-ceramic phase with a general chemical formula of Li ₃ YCl ₆ .

test case

The ionic conductivity of the electrolyte materials prepared in the above examples and comparative examples is tested as follows: Weigh 100 mg of electrolyte powder, place it in an insulating outer cylinder, pressurize it with a pressure of 300 MPa, and perform an AC impedance spectrum test. The ionic conductivity of the electrolyte material was calculated according to the impedance value, and the test results are shown in Table 1.

Table 1 Properties of electrolyte materials

It can be seen from Table 1 that the present invention introduces divalent and tetravalent ions simultaneously into the electrolyte components, flexibly adjusts the halide microstructure, optimizes the Li/hole ratio, and promotes the rapid exchange of lithium ions in the lattice. Shuttle can achieve the effect of greatly improving the conductivity of halide ions, reduce the use of scarce and expensive trivalent ions, reduce the cost of halide preparation, provide a new technical route and solution for the practical application of halide materials, and enrich halides Types of solid electrolyte materials and their practical application value.

Apparently, the above-mentioned embodiments are only examples for clear description, rather than limiting the implementation. For those of ordinary skill in the art, other changes or changes in different forms can be made on the basis of the above description. It is not necessary and impossible to exhaustively list all the implementation manners here. And the obvious changes or changes derived therefrom are still within the scope of protection of the present invention.

Claims (10)

1. A halide solid electrolyte material, characterized in that, the general chemical formula of the electrolyte material is LiaA _{1-x- y} M _x N _y X _3+a-x+y , wherein 1≤a≤6; 0.02 ≤x≤0.9; 0.02≤y≤0.9; A is selected from one or more of Ga ³⁺ , In ³⁺ , Fe ³⁺ , Y ³⁺ , Sc ³⁺ , and +3-valent La metals; M is selected from One or more of Cu ²⁺ , Zn ²⁺ , Cd ²⁺ , Mg ²⁺ , Ca ²⁺ , Sr ²⁺ , Ba ²⁺ ; N is selected from Zr ⁴⁺ , Hf ⁴⁺ , Ti ⁴⁺ One or more of; X is selected from one or more of F ^- , Cl ^- , Br ^- , I ^- ; Substituting the divalent ions represented by M for the trivalent ions represented by A will increase lithium ions and reduce holes, and the substitution of tetravalent ions represented by N for trivalent ions represented by A will increase holes and reduce lithium ions, divalent ions, tetravalent ions Ions and trivalent ions are mixed and arranged in the crystal lattice, resulting in local differences in electron cloud arrangement. 2. The halide solid electrolyte material according to claim 1, wherein A is selected from ^{Ga 3+} , In ³⁺ , Fe ³⁺ , Y ³⁺ , Sc ³⁺ , Ho ³⁺ , Er ³⁺ , One or more of Lu ³⁺ , Yb ³⁺ ; and/or, M is selected from one or more of Mg ²⁺ , Zn ²⁺ , Cu ²⁺ ; and/or, N is selected from Zr ^{4 +} and/or Hf ⁴⁺ ; And/or, 2.2≤a≤3.8; and/or, 0.1≤x≤0.5; and/or, 0.1≤y≤0.7. 3. The halide solid electrolyte material according to claim 2, wherein A is selected from Fe ³⁺ , and N is selected from Hf ⁴⁺ . 4. The halide solid electrolyte material according to any one of claims 1-3, characterized in that, the halide solid electrolyte material is in any form of a glass phase, a glass-ceramic phase or a crystalline phase. 5. The preparation method of the halide solid-state electrolyte material according to any one of claims 1-4, characterized in that, comprising the steps of: 1) mixing the raw materials in the formula ratio to obtain the mixture; 2) Grinding and sintering the mixture to obtain the halide solid electrolyte material. 6. The preparation method of the halide solid electrolyte material according to claim 5, characterized in that, in step 2), the mixture is ground by ball milling, the ball milling speed is 100-500 rpm, and the ball milling time is 1-50h ; The grinding step is carried out under an inert atmosphere; The sintering temperature is 200-600°C, and the holding time is 1-40h. 7. The preparation method of the halide solid electrolyte material according to claim 5 or 6, characterized in that, after the sintering in step 2), the step of grinding the sintered material is also included. 8. the preparation method of halide solid electrolyte material according to claim 5, is characterized in that, The raw materials described in step 1) are lithium source, A source, M source and N source, wherein the lithium source is lithium halide, and the A source is selected from Ga halide, In halide, Fe halide, Y halide , one or more of Sc halides and La-series metal halides; The M source is selected from one or more of Cu halides, Zn halides, Cd halides, Mg halides, Ca halides, Sr halides and Ba halides; The N source is selected from one or more of Zr halides, Hf halides and Ti halides. 9. A lithium secondary battery, comprising positive electrode layer, electrolyte layer and negative electrode layer, characterized in that at least one layer of said positive electrode layer, electrolyte layer and negative electrode layer contains any one of claims 1-4 The halide solid electrolyte material or the halide solid electrolyte material prepared by the preparation method described in any one of claims 5-8. 10. The lithium secondary battery according to claim 9, wherein the lithium secondary battery comprises a liquid phase lithium secondary battery, a semi-solid lithium secondary battery and an all-solid lithium secondary battery.