WO2020124648A1 - Application of fluorinated oxalate material, and product containing fluorinated oxalate material and preparation method therefor and use thereof - Google Patents

Abstract

The present application relates to the technical field of secondary batteries, and relates to an application of a fluorinated oxalate material, and a product containing the fluorinated oxalate material and a preparation method therefor and a use thereof. The present application provides an application of the fluorinated oxalate material as a positive active material in a potassium ion battery; the chemical formula of the fluorinated oxalate material is K_xM[C₂O₄]_yF_z, wherein M is at least one variable-valence transition metal, 0<x≤1, 0<y≤1, and 0<z≤1. The fluorinated oxalate material has an open three-dimensional network framework, has a large gap position for moving and storage of potassium ions, and maintains excellent structural stability during charging and discharging cycles, so that the potassium ion battery assembled from the fluorinated oxalate material as a positive material has a great discharge capacity, a long cycle life, a high energy density and power density, low costs, and a good application prospect.

Description

Application of fluorinated oxalate materials, products containing fluorinated oxalate materials, preparation methods and uses thereof

Cross-reference of related applications

This application requires the application number CN201811596064.7, which is submitted to the Chinese Patent Office on December 20, 2018, and is entitled "Application of Fluorinated Oxalate Materials and Products, Preparation Methods and Uses of Fluorinated Oxalate Materials" The priority of Chinese patent applications in China is incorporated in this application by reference.

Technical field

The present application belongs to the technical field of secondary batteries, and in particular, relates to the application of fluorinated oxalate materials, products containing fluorinated oxalate materials, preparation methods, and uses thereof.

Background technique

With the continuous development of social civilization, human demand for energy is increasing day by day. However, the traditional fossil energy has prominent problems such as resource depletion and environmental pollution, which seriously restricts the development of social economy. In order to solve the above problems, the development of clean energy such as solar energy, tidal energy and wind energy is an inevitable choice. In this process, energy conversion and storage are issues that must be faced. Secondary batteries have become the most important energy conversion and storage technology because of their high efficiency and low cost. At present, the main secondary batteries are lead-acid batteries, nickel-chromium batteries, nickel-metal hydride batteries and lithium-ion batteries. Among them, lithium ion batteries have been widely used in portable electronic products, pure electric vehicles and hybrid vehicles due to the advantages of large energy density, high operating voltage, long cycle life and low self-discharge rate. However, with the expansion of the application field of lithium-ion batteries and the rapid increase in demand year by year, the price of lithium with very limited reserves and uneven distribution in the world has continued to rise, which has caused the price of lithium-ion batteries to continue to rise, severely restricting low-cost and high-performance energy storage. Rapid development in the field of devices. Therefore, it is necessary to vigorously develop a new system of secondary batteries with excellent comprehensive performance that can replace lithium-ion battery technology.

Elements such as sodium, potassium, aluminum, and magnesium have similar chemical properties and excellent deintercalation characteristics to lithium, making their corresponding battery technologies very promising alternative technologies for lithium-ion batteries. Among them, potassium ions have the standard electrode potential closest to lithium ions, and potassium ions have a large ion migration rate in the electrolyte; in addition, potassium resources have a wide distribution (abundance in the crust is 2.09%, which is about lithium 1200 times) and the relatively low price of natural advantages, making potassium ion batteries more promising. Nevertheless, because the radius of potassium ions (r = 0.138 nm) is larger than the radius of lithium ions (0.068 nm), the diffusion kinetics of K ⁺ in common electrode materials for lithium ion batteries is much lower than that of Li ⁺ , so the appropriate potassium The ion battery electrode material must have a large channel that allows K ⁺ to pass through quickly, and still maintain a stable structure during the process of K ⁺ insertion and extraction. At present, the main materials used in the anode materials of potassium ion batteries are carbon material series, such as graphite, carbon black, hard carbon, soft carbon and graphene. However, there is still little research on potassium ion cathode materials. At present, mainly reported are organic compounds such as Prussian blue and its analogs, iron phosphate and iron fluorosulfate, etc., but this series of materials exists more or less Problems such as poor cycle stability, unstable structure, low capacity of the charging and discharging platform, and high cost of material preparation. Patent No. CN 108615874A discloses a positive electrode material for potassium ion batteries based on nickel-manganese binary oxides. Although its capacity can reach 93.38mAh/g, its coulombic efficiency is low and its cycle stability is poor; the publication number CN 107093739A The patent discloses a positive electrode material of potassium ion battery based on potassium manganese oxide, its capacity can reach 83.9mAh/g, but this material has poor cycle performance and discharge platform is not obvious; the patent number CN 105826521A discloses a polyanion based The compound's potassium ion battery cathode material, but its lower discharge platform (1.6V), resulting in a lower energy density; the publication number CN107226475A discloses a Prussian blue-based potassium ion battery cathode material, although its capacity can reach 90.7 mAh/g, cycle stability is good (400 cycles, capacity retention rate is 90.37%), but the material has the problems of poor controllability of operation and difficulty in mass production. Therefore, the research on the cathode materials of potassium ion batteries is still in its infancy, and it is urgent to develop new high-performance cathode materials for potassium ion batteries.

In view of this, this application is hereby submitted.

Summary of the invention

The first object of the present application is to provide a fluorinated oxalate material used as a positive electrode active material in a potassium ion battery, the fluorinated oxalate material is stable in structure and has an excellent K ⁺ transmission channel, which can be quickly stored K ⁺ , in turn, enables the potassium ion battery containing it to have a high energy density and power density, and a long cycle life, which can overcome the above problems or at least partially solve the above technical problems.

The second object of the present application is to provide a positive electrode material for a potassium ion battery, which contains a fluorinated oxalate material, which can overcome the above problems or at least partially solve the above technical problems.

The third object of the present application is to provide a positive electrode for a potassium ion battery, including the above positive electrode material for a potassium ion battery.

The fourth object of the present application is to provide a potassium ion battery including the positive electrode of the above potassium ion battery, which has the characteristics of long cycle life, high specific capacity, high energy density and power density.

The fifth object of the present application is to provide a method for preparing a potassium ion battery.

The sixth object of the present application is to provide an application of the above-mentioned potassium ion battery in an energy storage system or an electric device.

In order to achieve the above purpose, the technical solutions adopted in this application are:

According to an aspect of the present application, the present application provides a fluorinated oxalate material used as a positive electrode active material in a potassium ion battery;

The chemical formula of the fluorinated oxalate material is K _x M[C ₂ O ₄ ] _y F _z , where M is at least one variable-valence transition metal, 0<x≤1, 0<y≤1, 0 ＜z≤1.

According to another aspect of the present application, the present application provides a cathode material for a potassium ion battery, including a cathode active material, a conductive agent, and a binder;

Wherein, the positive electrode active material is a fluorinated oxalate material, and the chemical formula of the fluorinated oxalate material is K _x M[C ₂ O ₄ ] _y F _z , abbreviated as KMCF, where M is at least one Variable valence transition metals, 0<x≤1, 0<y≤1, 0<z≤1.

As a further preferred technical solution, the M is at least one of Ti, V, Cr, Mn, Fe, Co, Ni, Cu, and Zn;

Preferably, 0.1≤x≤1, 0.1≤y≤1, 0.1≤z≤1;

Preferably, x is 1, y is 1, and z is 1;

Preferably, the chemical formula of the fluorinated oxalate material is KFeC ₂ O ₄ F, KCoC ₂ O ₄ F, KTiC ₂ O ₄ F, KVC ₂ O ₄ F, KMnC ₂ O ₄ F, KNiC ₂ O ₄ F, KCuC ₂ O ₄ F, KCo _0.5 V _0.5 C ₂ O ₄ F, KCu _0.9 Ti _0.1 C ₂ O ₄ F, KCo _0.5 Ni _0.5 C ₂ O ₄ F, KFe _0.7 Ni _0.3 C ₂ O ₄ F, KFe _1/3 At least one of Co _1/3 Ni _1/3 C ₂ O ₄ F, KCo _0.2 Ni _0.3 Mn _0.5 C ₂ O ₄ F or KFe _0.25 Co _0.25 Ni _0.25 Mn _0.25 C ₂ O ₄ F;

Preferably, the chemical formula of the fluorinated oxalate material is KFeC ₂ O ₄ F, which belongs to an orthogonal system, the space group is Cmc2 ₁ , the decomposition temperature is 300° C., and the unit cell parameter is

α=β=γ=90°;

Preferably, the chemical formula of the fluorinated oxalate material is KMnC ₂ O ₄ F, which belongs to an orthogonal system, the space group is Cmc2 ₁ , the decomposition temperature is 305°C, and the unit cell parameter is

α=β=γ=90°;

Preferably, the chemical formula of the fluorinated oxalate material is KCoC ₂ O ₄ F, which belongs to an orthogonal system, the space group is Pmc2 ₁ , the decomposition temperature is 330° C., and the unit cell parameter is

α=β=γ=90°;

Preferably, preferably, the chemical formula of the fluorinated oxalate material is KNiC ₂ O ₄ F, which belongs to an orthogonal system, the space group is Pmc2 ₁ , the decomposition temperature is 325° C., and the unit cell parameter is

α=β=γ=90°.

As a further preferred technical solution, a potassium source, a transition metal source, an oxalate source, a fluorine source and an optional solvent are mixed to perform a solvothermal reaction to obtain the fluorinated oxalate material;

Preferably, the molar ratio of transition metal source, potassium source, oxalate source and fluorine source is 1: (2-8): (2-8): (2-8);

Preferably, the potassium source includes at least one of potassium-containing oxides, acids, bases or salts;

Preferably, the transition metal source includes a transition metal titanium source, a transition metal vanadium source, a transition metal chromium source, a transition metal manganese source, a transition metal iron source, a transition metal cobalt source, a transition metal nickel source, a transition metal copper source and a transition metal At least one of metal zinc sources;

Preferably, the transition metal source includes at least one of oxides, hydroxides, halides, acids, bases, salts or transition metal elements containing transition metals;

Preferably, the oxalate source includes at least one of oxalate-containing acid or salt;

Preferably, the fluorine source includes at least one of fluorine-containing acid, alkali or salt;

Preferably, the solvent includes at least one of water, alcohols, ketones or pyridines, preferably water;

Preferably, the temperature of the solvothermal reaction is 140-250°C, preferably 190-200°C;

And/or, the solvothermal reaction time is ≥24h, preferably 72-120h;

Preferably, the solvothermal reaction further includes steps of separation, washing and drying;

Preferably, the drying temperature is 40 to 120° C., the pressure is ≤20 kPa, and the time is 10 to 24 h.

As a further preferred technical solution, the positive electrode material includes 60 to 90 wt% of the positive electrode active material, 5 to 30 wt% of the conductive agent, and 5 to 10 wt% of the binder;

Preferably, the conductive agent includes at least one of conductive carbon black, conductive carbon spheres, conductive graphite, carbon nanotubes, carbon fiber, graphene or reduced graphene oxide;

Preferably, the binder includes at least one of polyvinylidene fluoride, polytetrafluoroethylene, polyvinyl alcohol, carboxymethyl cellulose, SBR rubber, or polyolefin-based binder.

According to another aspect of the present application, the present application provides a positive electrode for a potassium ion battery, including a positive electrode current collector and the foregoing positive electrode material for the potassium ion battery;

Preferably, the cathode current collector is any metal of aluminum, copper, iron, tin, zinc, nickel, titanium, or manganese; or, the cathode current collector is at least aluminum, copper, iron, tin, zinc , Nickel, titanium, or manganese; or, the positive electrode current collector is a metal composite material containing at least any one of aluminum, copper, iron, tin, zinc, nickel, titanium, or manganese.

According to another aspect of the present application, the present application provides a potassium ion battery, including a negative electrode, a positive electrode, a separator between the positive and negative electrodes, and an electrolyte;

Wherein, the positive electrode is the positive electrode of the above-mentioned potassium ion battery.

According to another aspect of the present application, the present application provides a method for preparing a potassium ion battery, which assembles a negative electrode, an electrolyte, a separator, and a positive electrode to obtain a potassium ion battery.

According to another aspect of the present application, the present application provides an application of the above-mentioned potassium ion battery in an energy storage system or electrical equipment.

Compared with the prior art, the beneficial effects of this application are:

(1) The fluorinated oxalate material is used as a positive electrode active material in potassium ion batteries. Because the fluorinated oxalate material has an open three-dimensional network frame structure, it has a large gap position for potassium ions to shuttle and store , And maintain excellent structural stability during the charge and discharge cycle, so that the potassium ion battery assembled from the fluorinated oxalate material as the cathode material has high discharge capacity, long cycle life, high energy density and Power density has good application prospects.

(2) The fluorinated oxalate material provided in this application has a typical polyanionic structure formula: K _x M[C ₂ O ₄ ] _y F _z , abbreviated as KMCF, in which oxalate ion C ₂ O ₄ and variable valence The transition metal ions M together form a layered skeleton structure of the space. The layers are bridged by fluorine atoms F. The rigidity of the skeleton is enhanced and the stability of the material is improved. The gap position of the frame can not only accommodate potassium ions And, the open channel formed by it can be used for the rapid desorption of potassium ions, and the framework can maintain the stability of its own structure during the potassium ion desorption process, which helps to improve the electrochemical performance of potassium ion batteries.

(3) Compared with the existing lithium-ion battery, the secondary battery completely replaces the lithium source with a potassium source, so that its application is not restricted by lithium resources, and the battery can be greatly developed. In addition, because the price of potassium salt is far Below the lithium salt, the production cost of the potassium ion battery is significantly reduced. In addition, the potassium ion battery provided by the present application also has the characteristics of long cycle life, high specific capacity, high energy density, high voltage platform and low cost.

(4) The method of this application is simple in process, easy to operate, low in raw material cost, low in equipment requirements, environmentally friendly, and suitable for large-scale industrial production.

(5) The energy storage system or electrical equipment provided by the present application includes the above-mentioned potassium ion battery, and therefore has at least the same advantages as the above-mentioned potassium ion battery, with low cost, high specific capacity, high energy density, high voltage platform and cycle The advantage of good performance is that the energy storage system or electrical equipment has a longer service life when used in the same charge and discharge current and the same environment.

BRIEF DESCRIPTION

In order to more clearly explain the specific embodiments of the present application or the technical solutions in the prior art, the following will briefly introduce the drawings required for the specific embodiments or the description of the prior art. Obviously, the appended The drawings are some embodiments of the present application. For those of ordinary skill in the art, without paying any creative work, other drawings can be obtained based on these drawings.

1 is a schematic diagram of the crystal structure of the fluorinated oxalate material K _x M[C ₂ O ₄ ] _y F _z provided in Example 1 of the present application;

2 is an optical photo of the fluorinated oxalate material K _x M[C ₂ O ₄ ] _y F _z crystal provided in Example 1 of the present application;

3 is an X-ray powder diffraction pattern (XRD pattern) of the fluorinated oxalate material provided in Example 11 of this application;

4 is a thermogravimetric analysis diagram of the fluorinated oxalate material provided in Example 1 of this application;

5 is a charge-discharge curve of a potassium ion battery including a fluorinated oxalate material KCoC ₂ O ₄ F provided in Example 1 of this application;

6 is a charge-discharge curve of a potassium ion battery including a fluorinated oxalate material KFeC ₂ O ₄ F provided in Example 110 of the present application;

7 is a long cycle diagram of a potassium ion battery including a fluorinated oxalate material KFeC ₂ O ₄ F provided in Example 110 of the present application;

8 is a schematic diagram of a potassium ion battery including a fluorinated oxalate material KMCF provided by an embodiment of the present application.

Icons: 1-positive electrode current collector; 2-positive electrode active material; 3-electrolyte; 4-separator; 5-negative electrode active material; 6-negative electrode current collector.

detailed description

The embodiments of the present application will be described in detail below in conjunction with the embodiments and examples, but those skilled in the art will understand that the following embodiments and examples are only used to illustrate the present application and should not be considered as limiting the scope of the present application. Based on the embodiments in the present application, all other embodiments obtained by a person of ordinary skill in the art without making creative efforts fall within the protection scope of the present application. If no specific conditions are indicated, follow the normal conditions or the conditions recommended by the manufacturer. The reagents or instruments used do not indicate the manufacturer, are all conventional products that can be obtained through commercial purchase.

It should be noted:

In this application, unless otherwise specified, all the embodiments and preferred implementation methods mentioned herein can be combined with each other to form a new technical solution.

In this application, if there is no special description, all the technical features and preferred features mentioned in this document can be combined with each other to form a new technical solution.

The forms of the "lower limit" and the upper limit disclosed in the "range" of this application may be one or more lower limits and one or more upper limits, respectively.

In this application, unless otherwise stated, each reaction or operation step may be performed sequentially or not. Preferably, the methods herein are performed sequentially.

Unless otherwise stated, the technical and scientific terms used in this article have the same meaning as those familiar to those skilled in the art. In addition, any method or material similar to or equivalent to the described content can also be applied to this application.

In a first aspect, in at least one embodiment, a fluorinated oxalate material is used as a positive electrode active material in a potassium ion battery;

The chemical formula of the fluorinated oxalate material is K _x M[C ₂ O ₄ ] _y F _z , where M is at least one variable-valence transition metal, 0<x≤1, 0<y≤1, 0 ＜z≤1.

According to this application, the chemical formula of the fluorinated oxalate material provided is K _x M[C ₂ O ₄ ] _y F _z , abbreviated as KMCF; where M is a variable-valent transition metal ion, and C ₂ O ₄ and the transition metal Forms a spatial layered skeleton structure, and the layers are connected by F bridge bonds. The material has an open three-dimensional network framework structure, which can accommodate potassium ions, and the positive electrode material can maintain its own structure during the desorption of potassium ions. stable.

The material is a polyanionic positive electrode active material with transition metal ions having electrochemical activity. It has an excellent potassium ion transmission channel, which can realize the rapid insertion and extraction of potassium ions, and the crystal structure is stable. During the insertion and extraction of potassium ions No phase change occurs in. In turn, the potassium ion battery containing the material has high discharge capacity, long cycle life, high energy density and power density, high charge and discharge voltage platform, and low cost, which can solve the price increase problem caused by insufficient lithium resources. It has a broader application prospect and can be widely used in power tools, electronic equipment, electric vehicles or energy storage equipment.

The raw materials used for the fluorinated oxalate material are inexpensive, easy to obtain, and are not restricted by the limited resources, which is of great significance for reducing the cost of the secondary battery; compared with the traditional oxide-type cathode active material, polyanion-type cathode active material The structure is more stable, which is of great significance for improving the safety, cycle life, energy density and specific capacity of secondary batteries.

It should be noted:

"At least one variable valence transition metal" means that the transition metal M has more than one valence and can realize the valence of the valence, and M can be a variable valence transition metal or two or more Combination of variable transition metals.

There are no specific restrictions on the specific values of x, y, and z in the material, and it may be within the range of 0 to 1 excluding 0, for example, each may be independently 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9 or 1.

In a second aspect, in at least one embodiment, a positive electrode material for a potassium ion battery is provided, including a positive electrode active material, a conductive agent, and a binder;

Wherein, the positive electrode active material is a fluorinated oxalate material, and the chemical formula of the fluorinated oxalate material is K _x M[C ₂ O ₄ ] _y F _z , where M is at least one variable-valent transition Metal, 0<x≤1, 0<y≤1, 0<z≤1.

Using the above-mentioned fluorinated oxalate material as a positive electrode active material, this type of potassium ion battery maintains a stable structure and high purity during the insertion/deintercalation process, and the potassium ion battery has high capacity, good cycle stability, and a charging and discharging voltage platform High energy density.

It should be understood that there is no special restriction on the type of transition metal M in this application, as long as the purpose of this application is not limited.

In a preferred embodiment, the M is at least one of Ti, V, Cr, Mn, Fe, Co, Ni, Cu, and Zn; that is, M includes but is not limited to titanium (Ti), vanadium ( V) one or more of chromium (Cr), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu) or zinc (Zn) and other variable-valent transition metals combination.

Preferably, 0.1≤x≤1, 0.1≤y≤1, 0.1≤z≤1;

Preferably, x is 1, y is 1, and z is 1.

According to the present application, the subscripts x, y, and z of potassium ion, oxalate ion, and fluoride ion are preferably any real numbers in the range of 0.1 to 1, and more preferably x, y, and z are all 1. The following mainly uses x, y, and z as examples for further detailed description, but it should be understood that fluorinated oxalate materials having similar structures are also within the scope of protection of the present application.

For example, when x, y, and z are all 1, the chemical formula of the fluorinated oxalate material may be KFeC ₂ O ₄ F, KCoC ₂ O ₄ F, KTiC ₂ O ₄ F, KVC ₂ O ₄ F, KMnC ₂ O ₄ F, KNiC ₂ O ₄ F, KCuC ₂ O ₄ F, KCo _0.5 V _0.5 C ₂ O ₄ F, KCu _0.9 Ti _0.1 C ₂ O ₄ F, KCo _0.5 Ni _0.5 C ₂ O ₄ F, KFe _0.7 Ni _0.3 C ₂ O ₄ F, KFe _1/3 Co _1/3 Ni _1/3 C ₂ O ₄ F, KCo _0.2 Ni _0.3 Mn _0.5 C ₂ O ₄ F or KFe _0.25 Co _0.25 Ni _0.25 Mn _0.25 C ₂ O ₄ F At least one of

It should be understood that the present application has no special restrictions on the ratio of each component in the mixed transition metal, as long as the purpose of the present application is not limited. For example, when M is a mixed transition metal Co and V, the ratio of Co and V can be 0.5:0.5, 0.6:0.4, or 0.8:0.2; when M is a mixed transition metal Cu and Ti, Cu and V The ratio of Ti may be 0.9:0.1, 0.8:0.2, 0.5:0.5, etc., and this application will not list them one by one here.

1 shows a schematic diagram of the crystal structure of a fluorinated oxalate material K _x M[C ₂ O ₄ ] _y F _z provided by an embodiment of the present application; FIG. 2 shows a fluorinated oxalic acid provided by an embodiment of the invention Optical photo of the salt material K _x M[C ₂ O ₄ ] _y F _z crystal. It can be seen that C ₂ O ₄ and the transition metal in this material together form a spatial layered skeleton structure, and the layers are connected by F. The material has an open three-dimensional network framework structure, which can accommodate potassium ions, and in potassium The positive electrode active material can maintain its structural stability during ion deintercalation.

It can be understood that the position of M in K _x M[C ₂ O ₄ ] _y F _z in FIG. 1 can be partially or completely replaced with transition metals Ti, V, Mn, Fe, Co, Ni, Cu or Zn, etc. . Similarly, FIG. 2 is an optical photo of the prepared KCoC ₂ O ₄ F positive electrode active material. As shown in FIG. 2, in K _x M[C ₂ O ₄ ] _y F _z , M can be Co, or Ti, V can be used. , Mn, Fe, Co, Ni, Cu or Zn one or more alternatives.

In a preferred embodiment, the chemical formula of the fluorinated oxalate material is KFeC ₂ O ₄ F, which belongs to an orthogonal system, the space group is Cmc2 ₁ , the decomposition temperature is 300° C., and the unit cell parameter is

α=β=γ=90°;

Preferably, the chemical formula of the fluorinated oxalate material is KMnC ₂ O ₄ F, which belongs to an orthogonal system, the space group is Cmc2 ₁ , the decomposition temperature is 305°C, and the unit cell parameter is

α=β=γ=90°;

Preferably, the chemical formula of the fluorinated oxalate material is KCoC ₂ O ₄ F, which belongs to an orthogonal system, the space group is Pmc2 ₁ , the decomposition temperature is 330° C., and the unit cell parameter is

α=β=γ=90°;

Preferably, preferably, the chemical formula of the fluorinated oxalate material is KNiC ₂ O ₄ F, which belongs to an orthogonal system, the space group is Pmc2 ₁ , the decomposition temperature is 325° C., and the unit cell parameter is

α=β=γ=90°.

According to the present application, the preparation method of the above-mentioned fluorinated oxalate material includes: mixing a potassium source, a transition metal source, an oxalate source, a fluorine source and an optional solvent, and performing a solvothermal reaction to obtain the fluorinated oxalate material .

It should be noted that "optional solvent" means that the solvent may or may not be added. For example, when a potassium source, oxalate source or fluorine source containing a hydrate is used, it can be dissolved by water in the hydrate as No additional solvent is needed.

The synthesis method of the present application is easy to operate, fast and safe, easy to implement, has good controllability, and the raw materials used are cheap and readily available. It plays an important role in optimizing the preparation process of battery materials and reducing the production cost of positive electrode active materials.

Preferably, the preparation method of the above-mentioned fluorinated oxalate material includes the following steps:

(1) Weigh the transition metal source, potassium source, oxalate source and fluorine source according to a certain ratio, add the weighed raw materials to the reaction kettle equipped with a certain amount of solvent in sequence, stir and mix evenly;

(2) Seal the reactor and perform hydrothermal reaction;

(3) After the hydrothermal reaction is completed, the precipitate formed by the reaction is separated, and after washing and vacuum drying, a fluorinated oxalate material is obtained. As shown in FIG. photo.

It should be noted that this application has no special restrictions on the sources of the potassium source, transition metal source, oxalate source and fluorine source used, and various raw materials well known to those skilled in the art may be used; if commercially available products can be used, It can also be prepared by a preparation method well known to those skilled in the art.

In a preferred embodiment, the transition metal source includes a transition metal titanium source, a transition metal vanadium source, a transition metal chromium source, a transition metal manganese source, a transition metal iron source, a transition metal cobalt source, a transition metal nickel source, At least one of a transition metal copper source and a transition metal zinc source;

Preferably, the transition metal source includes at least one of a transition metal-containing oxide, hydroxide, halide, acid, alkali, salt, or transition metal element.

Further, the source of the transition metal titanium includes elemental titanium, titanium dioxide, titanium dioxide, titanium (III) sulfate, titanium (IV) sulfate, titanium phosphate, potassium fluorotitanate, hexafluorotitanate, tetrabutyl titanate, titanium Tetraethyl acid, isopropyl titanate, titanium tetrachloride, titanium trichloride, titanium dihydride, ammonium fluorotitanate, titanium tetrafluoride, titanium dichloride, bis(acetylacetonyl)isopropyl One or more of titanate and its hydrate.

Preferably, the source of the transition metal titanium is titanium tetrafluoride, titanium (III) sulfate, titanium trichloride and hydrates thereof.

Further, the sources of transition metal vanadium include elemental vanadium, vanadium trioxide, vanadium dioxide, vanadium pentoxide, vanadium difluoride, vanadium trifluoride, vanadium tetrafluoride, vanadium pentafluoride, vanadium oxyfluoride, and Vanadium chloride, vanadium trichloride, vanadium tetrachloride, vanadium oxychloride, vanadium dibromide, vanadium tribromide, vanadium tetrabromide, ammonium metavanadate, potassium orthovanadate, potassium metavanadate, acetylacetone One or more of vanadium, vanadium acetylacetonate, vanadium triisopropoxide, vanadium tripropoxide and their hydrates.

Preferably, the source of the transition metal vanadium is vanadium dioxide, vanadium pentoxide, vanadium oxyfluoride and hydrates thereof.

Further, the transition metal chromium sources include elemental chromium, chromium trioxide, chromium dioxide, chromium trioxide, chromium hydroxide, chromium sulfate, chromite sulfate, lithium chromate, potassium dichromate, sodium dichromate, chromium Vanadium, chromium trifluoride, chromium dichloride, chromium trichloride, chromium bromide, chromium bromide, chromium orthophosphate, chromium metaphosphate, chromium pyrophosphate, chromium phosphate, chromium phosphate, chromium nitrate, nitric acid At least one of chromite, chromium formate, cadmium acetate, chromite acetate, or chromium oxalate.

Preferably, the transition metal chromium source is chromium trioxide, chromium dichloride and their hydrates.

Further, the sources of transition metal manganese include elemental manganese, manganese oxide, manganese dioxide, trimanganese tetraoxide, manganese (II) fluoride, manganese (III) fluoride, manganese (II) chloride, manganese (III) chloride , Manganese bromide, manganese carbonate, manganese nitrate, manganese sulfate, manganese phosphate, manganese dihydrogen phosphate, manganese acetylacetonate, manganese formate, manganese (II) acetate, manganese (III) acetate, manganese oxalate and one of its hydrates One or more.

Preferably, the source of transition metal manganese is manganese acetate, manganese oxalate, manganese chloride and hydrates thereof.

Further, the sources of transition metal iron include elemental iron, ferric oxide, ferric oxide, ferrous hydroxide, ferric hydroxide, ferrous fluoride, ferric fluoride, ferrous chloride, ferric chloride, bromide One or more of ferrous iron, ferric bromide, ferric formate, ferrous acetate, ferrous nitrate, ferrous sulfate, ferric nitrate, ferric sulfate, ferric acetylacetonate, ferrous oxalate, ferric oxalate and their hydrates.

Preferably, the source of transition metal iron is ferrous oxalate, ferrous chloride and hydrates thereof.

Further, the transition metal cobalt sources include elemental cobalt, cobalt monoxide, cobalt trioxide, tricobalt tetroxide, cobalt(II) hydroxide, cobalt(III) hydroxide, cobalt(II) fluoride, cobalt(III) fluoride, Cobalt(II) chloride, cobalt(III) chloride, cobalt bromide, cobalt nitrate, cobalt sulfate, cobalt carbonate, cobalt acetate, cobalt oxalate, hexaaminocobalt chloride, cobalt acetylacetonate, and one of its hydrates Or more.

Preferably, the source of the transition metal cobalt is cobalt acetate, cobalt oxalate, cobalt chloride and hydrates thereof.

Further, the transition metal nickel sources include elemental nickel, nickel oxide, high nickel oxide, nickel hydroxide, high nickel hydroxide, nickel fluoride, nickel chloride, nickel bromide, nickel nitrate, nickel carbonate, nickel sulfate, nickel acetate , Nickel oxalate, nickel bis(hexafluoroethylacetone), nickel sulfamate, basic nickel carbonate, nickel acetylacetonate dihydrate, nickel trifluoromethanesulfonate, nickel benzenesulfonate, nickel acetylacetonate and fluoroboric acid One or more of nickel.

Preferably, the nickel source is nickel oxalate, nickel chloride, nickel fluoride, nickel acetate and hydrates thereof.

Further, the transition metal copper sources include elemental copper, cuprous oxide, copper oxide, copper hydroxide, copper fluoride, cuprous chloride, copper chloride, copper bromide, copper carbonate, basic copper carbonate, copper nitrate, One or more of copper sulfate, copper acetate, copper oxalate, copper tartrate, copper citrate, copper fluoroborate, copper acetylacetonate, copper gluconate, and hydrates thereof.

Preferably, the source of the transition metal copper is copper acetate, copper citrate, copper sulfate, cuprous chloride, copper chloride and hydrates thereof.

Further, the transition metal zinc sources include elemental zinc, zinc oxide, zinc hydroxide, zinc fluoride, zinc chloride, zinc bromide, zinc iodide, zinc sulfate, zinc nitrate, zinc carbonate, zinc acetate, zinc oxalate, lemon One or more of zinc acid, zinc fluoroborate, zinc tartrate, zinc borate, zinc metaborate, zinc acetylacetonate, zinc gluconate and their hydrates.

Preferably, the source of the transition metal zinc is zinc sulfate, zinc chloride and hydrates thereof.

In a preferred embodiment, the potassium source includes at least one of potassium-containing oxides, acids, bases, or salts;

Preferably, the potassium source is potassium carbonate, potassium acetate, potassium nitrite, potassium fluoroborate, potassium bromide, potassium sulfate, potassium oxalate, potassium persulfate, potassium hydroxide, potassium pyrosulfate, potassium dihydrogen phosphate, hydrogen phosphate Dipotassium, potassium pyrosulfite, potassium pyrophosphate, potassium chromate sulfate, potassium hydrogen tartrate, potassium dichromate, potassium hydrogen phthalate, potassium hydrogen oxalate, potassium sulfite, potassium sorbate, potassium fluorosilicate, phosphoric acid One or more of tripotassium, potassium gluconate, potassium oleate and their hydrates.

Preferably, the potassium source is potassium carbonate.

In a preferred embodiment, the oxalate source is derived from at least one of oxalate-containing acids or salts;

Preferably, the source of oxalic acid is one or more of oxalic acid, potassium oxalate, potassium hydrogen oxalate, ammonium oxalate, diethyl oxalate, and hydrates thereof;

Preferably, the source of oxalic acid is oxalic acid.

In a preferred embodiment, the fluorine source includes at least one of a fluorine-containing acid, alkali or salt;

Preferably, the fluorine source is potassium fluoroborate, potassium fluorosilicate, potassium fluorotantalate, ammonium fluoroborate, diethyl fluoromalonate, potassium fluorotitanate, 3,5-difluorobenzylamine, 2,6 -One or more of difluorobenzoic acid, 2-chloro-4-fluorobenzoic acid, 3-fluoro-5-bromoaniline, heptafluorobutyric acid, m-trifluoromethylcinnamoyl chloride and perfluorooctanoic acid.

Preferably, the fluorine source is potassium fluoroborate.

In a preferred embodiment, the solvent includes at least one of water, alcohols, ketones or pyridines, preferably water.

It should be understood that the specific type of solvent used in the solvothermal reaction is not particularly limited in this application, including but not limited to the above types, such as one of water, methanol, ethanol, acetone, ethylene glycol and pyridine, or Various, the solvent is preferably water. Water may be derived from raw materials containing water, or a certain amount of water may be added to the reaction.

In a preferred embodiment, the molar ratio of transition metal source, potassium source, oxalate source and fluorine source is 1: (2-8): (2-8): (2-8); typical but not limited, For example, it can be 1:2:4:4, 1:4:8:8, 1:3:5:8, 1:6:6:6, 1:5:5:8 or 1:6:7:8 . The suitable raw materials have better overall performance than the prepared cathode active material, and can better play the role of the cathode active material in the system battery.

In a preferred embodiment, the order of adding the transition metal source, potassium source, oxalate source and fluorine source in the above step (1) can be adjusted arbitrarily;

Preferably, the raw materials are added in the order of transition metal source, oxalate source, potassium source, and fluorine source.

In a preferred embodiment, the temperature of the solvothermal reaction is 140-250°C, preferably 190-200°C; typical but not limited, for example, 140°C, 150°C, 160°C, 180°C, 200°C , 250℃ or 260℃.

Preferably, the solvothermal reaction time is ≥ 24h, preferably 72-120h; typical but not limited, for example, it can be 24h, 48h, 72h, 76h, 80h, 90h, 100h, 110h, 120h, 130h, 140h or 150h Wait. Appropriate reaction temperature and reaction time can make each raw material react more fully, increase the reaction rate, and the cathode active material obtained has more excellent electrochemical performance.

Preferably, the solvothermal reaction further includes steps of separation, washing and drying;

Preferably, the drying temperature is 40 to 120° C., the pressure is ≤20 kPa, and the time is 10 to 24 h.

According to the present application, in the above step (3), after the hydrothermal reaction is completed, the precipitate formed by the reaction may be separated by centrifugation or filtration, and then the precipitate is washed with water or absolute ethanol, and then vacuum dried. Vacuum drying is drying under the condition of pressure ≤20kPa and temperature of 40～120℃ for 10～24h.

In a preferred embodiment, the positive electrode material includes 60 to 90 wt% of the positive electrode active material, 5 to 30 wt% of the conductive agent, and 5 to 10 wt% of the binder.

It can be understood that the present application has no particular restrictions on the conductive agent and the binder, and only those commonly used in the art may be used.

Preferably, the conductive agent includes but is not limited to at least one of conductive carbon black, conductive carbon spheres, conductive graphite, carbon nanotubes, carbon fiber, graphene or reduced graphene oxide;

Preferably, the binder includes, but is not limited to, at least one of polyvinylidene fluoride, polytetrafluoroethylene, polyvinyl alcohol, carboxymethyl cellulose, SBR rubber, or polyolefin-based binder.

In a third aspect, in at least one embodiment, a positive electrode for a potassium ion battery is provided, including a positive electrode current collector and the positive electrode material for the potassium ion battery.

It can be understood that the core of the positive electrode of the potassium ion battery is that it contains the foregoing positive electrode material of the potassium ion battery, and there is no special restriction on the specific type of the positive electrode current collector.

Preferably, the positive electrode current collector is any metal of aluminum, copper, iron, tin, zinc, nickel, titanium or manganese; or, the positive electrode current collector is at least aluminum, copper, iron, tin, zinc , Nickel, titanium, or manganese; or, the positive electrode current collector is a metal composite material containing at least any one of aluminum, copper, iron, tin, zinc, nickel, titanium, or manganese.

According to a fourth aspect, in at least one embodiment, a potassium ion battery is provided, including a negative electrode, a positive electrode, a separator interposed between positive and negative electrodes, and an electrolyte;

Wherein, the positive electrode is the aforementioned positive electrode of the potassium ion battery.

It can be understood that the present application does not make special restrictions on the remaining components of the potassium ion secondary battery except the positive electrode active material. The core of the potassium ion secondary battery is that it contains the positive electrode active material of the present application, and the remaining components or components can be Refer to existing technology.

Referring to FIG. 8, the basic structure of a potassium ion battery containing the foregoing positive electrode active material is shown in FIG. 8. A potassium ion battery includes: a battery positive electrode current collector (1), a battery positive electrode active material (2), and an electrolyte ( 3), separator (4), battery negative active material (5) and battery negative current collector (6), and battery case for packaging (not shown). When metal foil is used as the negative electrode active material, the negative electrode current collector (6) is not required; the electrolyte solution (3) is a mixed solution of potassium salt electrolyte and organic solvent and additives; the battery positive electrode active material (2) is as described above Fluorinated oxalate material.

Preferably, the negative electrode active material includes carbon materials, metal oxides, sulfides, selenides, tellurides, metals, and alloys thereof.

Preferably, the negative electrode current collector includes one of aluminum, copper, iron, tin, zinc, nickel, titanium and manganese or the aforementioned alloy or the aforementioned composite material; the positive electrode current collector includes aluminum, copper, iron, tin, zinc, One of nickel, titanium and manganese or the aforementioned alloy or the aforementioned composite material.

Further, the anode current collector is preferably aluminum, and the cathode current collector is preferably aluminum.

In the embodiments of the present application, the solvent in the electrolyte is not particularly limited, as long as the solvent can dissociate the electrolyte into cations and anions, and the cations and anions can freely migrate. For example, the solvents in the embodiments of the present application include organic solvents such as esters, sulfones, ethers, nitriles, or ionic liquids. Specifically, including propylene carbonate (PC), ethylene carbonate (EC), diethyl carbonate (DEC), dimethyl carbonate (DMC), ethyl methyl carbonate (EMC), methyl formate (MF), acetic acid Methyl ester (MA), N,N-dimethylacetamide (DMA), fluoroethylene carbonate (FEC), methyl propionate (MP), ethyl propionate (EP), ethyl acetate (EA) , Γ-butyrolactone (GBL), tetrahydrofuran (THF), 2-methyltetrahydrofuran (2MeTHF), 1,3-dioxolane (DOL), 4-methyl-1,3-dioxolane Alkane (4MeDOL), dimethoxymethane (DMM), 1,2-dimethoxypropane (DMP), triethylene glycol dimethyl ether (DG), dimethyl sulfone (MSM), dimethyl ether (DME) , Vinyl sulfite (ES), propylene sulfite (PS), dimethyl sulfite (DMS), diethyl sulfite (DES), crown ether (12-crown-4), 1-ethyl- 3-methylimidazole-hexafluorophosphate, 1-ethyl-3-methylimidazole-tetrafluoroborate, 1-ethyl-3-methylimidazole-bistrifluoromethylsulfonimide salt, 1-propyl-3-methylimidazole-hexafluorophosphate, 1-propyl-3-methylimidazole-tetrafluoroborate, 1-propyl-3-methylimidazole-bistrifluoromethylsulfonate Imide salt, 1-butyl-1-methylimidazole-hexafluorophosphate, 1-butyl-1-methylimidazole-tetrafluoroborate, 1-butyl-1-methylimidazole-bis Trifluoromethylsulfonimide salt, N-butyl-N-methylpyrrolidine-bistrifluoromethylsulfonimide salt, 1-butyl-1-methylpyrrolidine-bistrifluoromethyl Sulfoimide salt, N-methyl-N-propylpyrrolidine-bistrifluoromethylsulfonimide salt, N-methyl, propylpiperidine-bistrifluoromethylsulfonimide salt and N -One or more of methyl, butyl piperidine-bis-trifluoromethylsulfonimide salt.

In the examples of the present application, the potassium salt as the electrolyte is also not particularly limited, as long as it can be dissociated into cations and anions, for example, it may include potassium hexafluorophosphate, potassium chloride, potassium fluoride, potassium sulfate, potassium carbonate, phosphoric acid Potassium, potassium nitrate, potassium difluorooxalate borate, potassium pyrophosphate, potassium dodecylbenzenesulfonate, potassium dodecyl sulfate, tripotassium citrate, potassium metaborate, potassium borate, potassium molybdate, potassium tungstate , Potassium bromide, potassium nitrite, potassium iodate, potassium iodide, potassium silicate, potassium lignosulfonate, potassium oxalate, potassium aluminate, potassium methanesulfonate, potassium acetate, potassium dichromate, hexafluoroarsenic acid One or more of potassium, potassium tetrafluoroborate, potassium perchlorate and potassium trifluoromethanesulfonimide (KTFSI), KCF ₃ SO ₃ , KN (SO ₂ CF ₃ ) ₂ , and the concentration range is 0.1 ~ 10mol /L.

Preferably, the electrolyte potassium salt is preferably potassium hexafluorophosphate.

In the embodiment of the present application, additives are added to the electrolyte. The additives include one or more of organic additives such as esters, sulfones, ethers, nitriles, or olefins. The amount of additives added to the electrolyte is 0.1-20 wt%. Additives include fluoroethylene carbonate, vinylene carbonate, ethylene ethylene carbonate, 1,3-propane sultone, 1,4-butane sultone, vinyl sulfate, propylene sulfate, ethylene sulfate Ester, vinyl sulfite, propylene sulfite, dimethyl sulfite, diethyl sulfite, ethylene sulfite, methyl chloroformate, dimethyl sulfoxide, anisole, acetamide , Diazabenzene, m-diazepine, crown ether 12-crown-4, crown ether 18-crown-6, 4-fluoroanisole, fluorochain ether, difluoromethyl vinyl carbonate, Trifluoromethylethylene carbonate, chloroethylene carbonate, bromoethylene carbonate, trifluoroethylphosphonic acid, bromobutyrolactone, fluoroacetoxyethane, phosphate, phosphite, phosphazene , Ethanolamine, carbamide, cyclobutyl sulfone, 1,3-dioxolane, acetonitrile, long-chain olefins, aluminum oxide, magnesium oxide, barium oxide, sodium carbonate, calcium carbonate, carbon dioxide, sulfur dioxide and One or more of lithium carbonate.

Further, the composition of the separator used in the new secondary battery provided by the embodiments of the present application is an insulating porous polymer film or an inorganic porous film, and porous polypropylene film, porous polyethylene film, porous composite polymer film, glass One or more of fiber paper or porous ceramic membrane.

Preferably, the positive electrode active material layer provided in the embodiment of the present application further includes a conductive agent and a binder, wherein the portion of the positive electrode active material is 60 to 90 wt%, the content of the conductive agent is 5 to 30 wt%, and the content of the binder is 5～10wt%. At the same time, the conductive agent and the binder are not particularly limited, and only those commonly used in the art may be used. The conductive agent is one or more of conductive carbon black, conductive carbon spheres, conductive graphite, carbon nanotubes, conductive carbon fiber, graphene and reduced graphene oxide. The binder is one or more of polyvinylidene fluoride, polytetrafluoroethylene, polyvinyl alcohol, carboxymethyl cellulose, SBR rubber, and polyolefin.

Potassium ion battery assembled with fluorinated oxalate cathode active material. Because the cathode material of the potassium ion battery has an open three-dimensional network frame structure, it has a large gap position for potassium ion shuttle and storage, and during the charge and discharge cycle The excellent structural stability is maintained, so that the potassium ion battery assembled from the positive electrode material of the potassium ion battery has high discharge capacity, long cycle life, high energy density and power density, and has good application prospects.

According to a fifth aspect, in at least one embodiment, a method for preparing a potassium ion battery is provided, in which a negative electrode, an electrolyte, a separator, and a positive electrode are assembled to obtain a potassium ion battery.

The above method is simple, safe, efficient, and easy to implement. The raw materials used are rich in reserves, low in price, and easy to obtain, which reduces the manufacturing cost of the battery.

The structural shape of the potassium ion battery is not limited, and may be a button battery, a column battery or a soft-pack battery.

In a preferred embodiment, the method for manufacturing the battery includes:

Step 1): Preparation of the negative electrode of the battery: the metal foil is cut to the required size, and then dried as the negative electrode of the battery and the current collector of the negative electrode, or the negative electrode active material, the conductive agent and the binder are weighed according to a certain ratio, and the appropriate solvent is added Fully mixed into a uniform slurry to make a negative electrode active material layer; clean the negative electrode current collector, then uniformly apply the negative electrode active material layer on the surface of the negative electrode current collector, and cut after the negative electrode active material layer is completely dried Cut to get the negative battery of the required size;

Step 2): Preparation of electrolyte: Weigh a certain amount of potassium salt electrolyte into the corresponding solvent, and stir to dissolve.

Step 3): Preparation of the diaphragm: the diaphragm is cut to a desired size, and cleaned.

Step 4): prepare the positive electrode of the battery, weigh the positive electrode active material, conductive agent and binder in a certain proportion, add an appropriate solvent and fully mix into a uniform slurry to make a positive electrode active material layer; clean the positive electrode current collector, and then The positive electrode active material layer is evenly coated on the surface of the positive electrode current collector, and the positive electrode active material layer is completely dried and then cut to obtain a battery positive electrode of a desired size;

Step 5): Assemble using the battery negative electrode, electrolyte, separator and battery positive electrode.

It should be noted that although the above steps 1) to 4) describe the operations of the preparation method of the present application in a specific order, this does not require or imply that these operations must be performed in the specific order. The preparation of steps 1)-4) can be performed simultaneously or in any order.

The preparation method of the secondary battery is based on the same inventive concept as the foregoing secondary battery, and the secondary battery obtained by using the preparation method of the secondary battery has all the effects of the foregoing secondary battery, which will not be repeated here.

According to a sixth aspect, in at least one embodiment, the application of the above-mentioned potassium ion battery in an energy storage system or an electric device is provided.

The above energy storage system or electrical equipment includes the above potassium ion battery, so it has at least the same advantages as the above potassium ion battery, with low cost, high discharge capacity, high specific capacity, high energy density, high power density and cycle performance Good advantages, easy to promote and apply.

The above-mentioned energy storage system refers to a power storage system that mainly uses the above-mentioned potassium ion battery as a power storage source; the above-mentioned electrical equipment includes, but is not limited to, electronic devices, power tools, or electric vehicles. The same effect can be obtained by using the power tool, electronic equipment, electric vehicle or large-scale energy storage device of the potassium ion battery of the present application.

It can be understood that the above-mentioned potassium ion battery can be mainly used in electric vehicles, energy storage batteries, power batteries, and energy storage power stations.

At the same time, the above-mentioned embodiments are only preferred embodiments of the present application, which cannot be used to limit the scope of protection of the present application. Any non-substantial changes and replacements made by those skilled in the art on the basis of the present application belong to the present Apply for the scope of protection required.

The following further describes the application of the above-mentioned fluorinated oxalate materials, as well as products containing the fluorinated oxalate and preparation methods thereof through specific examples, but it should be understood that these examples are only for more detailed description It should not be construed as limiting the application in any form.

Example 1

A preparation method of potassium ion battery includes:

(1) Weigh 1g water into 50mL polytetrafluoroethylene lining, add 0.238g CoCl ₂ · 6H ₂ O, 0.378g H ₂ C ₂ O ₄ · 2H ₂ O, 0.252g KBF ₄ and 0.276g K ₂ CO ₃ , mix and stir evenly;

(2) Seal the reaction kettle and install it in a stainless steel shell, and place it in a 200°C oven for 72 hours;

(3) After the reaction kettle cools down, collect the crystals obtained by the reaction and wash them with water and ethanol;

(4) The obtained crystal particles are ball-milled to a certain size, a certain amount of Super P conductive carbon balls are added, and the ball milling is performed again. After the end, polyvinylidene fluoride is added to be fully mixed. Positive electrode active material: Super P conductive carbon balls: poly Vinylidene fluoride=6:3:1, add 2mL of nitromethylpyrrolidone solution and mix thoroughly to form a uniform slurry to make a positive electrode active material layer; clean the positive electrode current collector, then apply the positive electrode active material layer evenly The surface of the positive electrode current collector, after the positive electrode active material layer is completely dried, it is cut into a 10mm battery positive electrode;

(5) Cut the glass fiber separator into 16mm diameter wafers and dry it as a battery separator;

(6) Weigh a certain amount of potassium hexafluorophosphate electrolyte into the mixed solvent of ethylene carbonate and dimethyl carbonate with a volume ratio of 1:1, stir and dissolve it fully, and configure it as an electrolyte with a concentration of 1M;

(7) Press the metal potassium into thin slices and cut out the negative electrode of the 12mm wafer;

(8) Battery assembly: In an inert gas-protected glove box, the above-mentioned prepared negative electrode current collector, separator and battery positive electrode are stacked closely in sequence, and the electrolyte is added dropwise to completely infiltrate the separator, and then the above-mentioned stacked part is packaged into a button type Battery case to complete battery assembly.

Example 2-65

Example 2-65 is an example of KMCF hydrothermal synthesis, wherein Examples 2-25 only change the type of transition metal source compared to Example 1 (the potassium source of Examples 20-25 is KOH); Examples 26-31 Compared with Example 1, only the type of potassium source was changed; Examples 32-35 changed only the type of oxalic acid source compared with Example 1; Examples 36-39 changed only the type of fluorine source compared with Example 1; Example 40- 45 compared with Example 1 only changed the raw material ratio; Examples 46-50 compared with Example 1 only changed the type of solvent; Examples 51-60 compared with Example 1 only changed the hydrothermal reaction temperature; Example 61- 65 Compared with Example 1, only the hydrothermal reaction time was changed. Specific operating conditions are shown in Table 1.

Table 1 Preparation conditions of fluorinated oxalate materials of Examples 1-65

Examples 66-109

Examples 66-109 are examples of potassium ion batteries using KMCF as a positive electrode active material, wherein examples 66-70 only change the type of conductive agent compared to example 1; examples 71-75 compare to example 1 only Change the type of binder; Examples 76-80 only change the positive electrode active material: conductive agent: binder ratio compared to Example 1; Examples 81-85 only change the type of positive electrode current collector compared to Example 1; Examples 86-90 compared with Example 1 only changed the electrolyte salt ratio; Examples 91-95 compared with Example 1 only changed the electrolyte solvent type; Examples 96-100 compared with Example 1 only changed the salt concentration ; Examples 101-104 only change the kind of separator compared to Example 1; Examples 105-109 only change the kind of negative electrode active material compared to Example 1. Specific operating conditions are shown in Table 2.

Table 2 Preparation conditions of the potassium ion batteries of Examples 66-109

Examples 110-122

Examples 110-122 are examples of potassium ion batteries using KMCF as a positive electrode active material. The difference between Examples 110-122 and Example 1 is the type of positive electrode active material, as shown in Table 3.

Table 3 Positive active materials in the potassium ion batteries of Examples 110-122

Examples	Positive active material
110	KFeC 2 O 4 F
111	KTiC 2 O 4 F
112	KVC 2 O 4 F
113	KMnC 2 O 4 F
114	KNiC 2 O 4 F
115	KCuC 2 O 4 F

116	KCo 0.5 V 0.5 C 2 O 4 F
117	KCu 0.9 Ti 0.1 C 2 O 4 F
118	KCo 0.5 Ni 0.5 C 2 O 4 F
119	KFe 0.7 Ni 0.3 C 2 O 4 F
120	KFe 1/3 Co 1/3 Ni 1/3 C 2 O 4 F
121	KCo 0.2 Ni 0.3 Mn 0.5 C 2 O 4 F
122	KFe 0.25 Co 0.25 Ni 0.25 Mn 0.25 C 2 O 4 F

Comparative Example 1

A potassium ion battery, which differs from Example 1 in the positive electrode active material;

In this comparative example, the cathode active material is the existing material K _0.3 MnO ₂ .

Comparative Example 2

A potassium ion battery, which differs from Example 1 in the positive electrode active material;

In this comparative example, the positive electrode active material is existing KFe ₂ (CN) ₆ .

Performance Testing

The performance tests of the above-mentioned partial examples and comparative examples of potassium ion batteries were performed, including constant current charge and discharge tests; for test results, see Table 4.

Among them, the constant current charge and discharge test uses a commercially available battery tester, the environment is a constant temperature and humidity room (30 ℃, 35%), the battery positive load is 2-5mg/cm ² , and the battery charge and discharge current density is 100mA/g. The initial upper and lower limits of the test voltage are set to 1.5V and 4.6V, and the number of cycles is set to 1000 cycles; when the specific capacity drops to 50% of the initial specific capacity, the test is manually stopped.

Table 4 Performance results of some examples and comparative examples of potassium ion batteries

It can be seen from Table 3 that the potassium ion battery provided by the present application has a higher stable specific capacity than known electrode materials, and the battery capacity decay is slow and the cycle is stable.

In addition, FIG. 5 shows the charge-discharge curve of the potassium ion battery including the fluorinated oxalate material KCoC ₂ O ₄ F provided in Example 1 of the present application; FIG. 6 shows the fluorinated oxalate provided in Example 110 of the present application The charging and discharging curve of the potassium ion battery of the material KFeC ₂ O ₄ F; FIG. 7 is a long cycle diagram of the potassium ion battery including the fluorinated oxalate material KFeC ₂ O ₄ F provided in Example 110 of the present application; It can be seen from the table that applying the fluorinated oxalate material of the present application as a positive electrode active material in a potassium ion battery can make the potassium ion battery have a high discharge capacity, a long cycle life, and excellent electrochemical performance.

Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: The technical solutions described in the foregoing embodiments can still be modified, or some or all of the technical features can be equivalently replaced; and these modifications or replacements do not deviate from the essence of the corresponding technical solutions of the technical solutions of the embodiments of the present application. range.

Claims (10)

1. Application of fluorinated oxalate material as positive electrode active material in potassium ion battery;

   The chemical formula of the fluorinated oxalate material is K _x M[C ₂ O ₄ ] _y F _z , where M is at least one variable-valence transition metal, 0<x≤1, 0<y≤1, 0 ＜z≤1.
2. The application according to claim 1, wherein the M is at least one of Ti, V, Cr, Mn, Fe, Co, Ni, Cu, and Zn;

   Preferably, 0.1≤x≤1, 0.1≤y≤1, 0.1≤z≤1;

   Preferably, the x is 1, the y is 1, and the z is 1;

   Preferably, the chemical formula of the fluorinated oxalate material is KFeC ₂ O ₄ F, KCoC ₂ O ₄ F, KTiC ₂ O ₄ F, KVC ₂ O ₄ F, KMnC ₂ O ₄ F, KNiC ₂ O ₄ F, KCuC ₂ O ₄ F, KCo _0.5 V _0.5 C ₂ O ₄ F, KCu _0.9 Ti _0.1 C ₂ O ₄ F, KCo _0.5 Ni _0.5 C ₂ O ₄ F, KFe _0.7 Ni _0.3 C ₂ O ₄ F, KFe _1/3 At least one of Co _1/3 Ni _1/3 C ₂ O ₄ F, KCo _0.2 Ni _0.3 Mn _0.5 C ₂ O ₄ F or KFe _0.25 Co _0.25 Ni _0.25 Mn _0.25 C ₂ O ₄ F;

   Preferably, the chemical formula of the fluorinated oxalate material is KFeC ₂ O ₄ F, which belongs to an orthogonal system, the space group is Cmc2 ₁ , the decomposition temperature is 300° C., and the unit cell parameter is

   

   α=β=γ=90°;

   Preferably, the chemical formula of the fluorinated oxalate material is KMnC ₂ O ₄ F, which belongs to an orthogonal system, the space group is Cmc2 ₁ , the decomposition temperature is 305°C, and the unit cell parameter is

   

   α=β=γ=90°;

   Preferably, the chemical formula of the fluorinated oxalate material is KCoC ₂ O ₄ F, which belongs to an orthogonal system, the space group is Pmc2 ₁ , the decomposition temperature is 330° C., and the unit cell parameter is

   

   α=β=γ=90°;

   Preferably, preferably, the chemical formula of the fluorinated oxalate material is KNiC ₂ O ₄ F, which belongs to an orthogonal system, the space group is Pmc2 ₁ , the decomposition temperature is 325° C., and the unit cell parameter is

   

   α=β=γ=90°.
3. The use according to claim 1 or 2, characterized in that a potassium source, a transition metal source, an oxalate source, a fluorine source and an optional solvent are mixed to perform a solvothermal reaction to obtain the fluorinated oxalate material;

   Preferably, the molar ratio of the transition metal source, potassium source, oxalate source and fluorine source is 1: (2-8): (2-8): (2-8);

   Preferably, the potassium source includes at least one of potassium-containing oxides, acids, bases or salts;

   Preferably, the transition metal source includes a transition metal titanium source, a transition metal vanadium source, a transition metal chromium source, a transition metal manganese source, a transition metal iron source, a transition metal cobalt source, a transition metal nickel source, a transition metal copper source and a transition metal At least one of metal zinc sources;

   Preferably, the transition metal source includes at least one of oxides, hydroxides, halides, acids, bases, salts or transition metal elements containing transition metals;

   Preferably, the oxalate source includes at least one of oxalate-containing acid or salt;

   Preferably, the fluorine source includes at least one of fluorine-containing acid, alkali or salt;

   Preferably, the solvent includes at least one of water, alcohols, ketones or pyridines, preferably water;

   Preferably, the temperature of the solvothermal reaction is 140-250°C, preferably 190-200°C;

   And/or, the solvothermal reaction time is ≥24h, preferably 72-120h;

   Preferably, the solvothermal reaction further includes steps of separation, washing and drying;

   Preferably, the drying temperature is 40 to 120° C., the pressure is ≤20 kPa, and the time is 10 to 24 h.
4. A positive electrode material for potassium ion battery, characterized in that it includes positive electrode active material, conductive agent and binder;

   Wherein, the positive electrode active material is a fluorinated oxalate material, and the chemical formula of the fluorinated oxalate material is K _x M[C ₂ O ₄ ] _y F _z , where M is at least one variable-valent transition Metal, 0<x≤1, 0<y≤1, 0<z≤1.
5. The positive electrode material for a potassium ion battery according to claim 4, wherein the M is at least one of Ti, V, Cr, Mn, Fe, Co, Ni, Cu, and Zn;

   Preferably, 0.1≤x≤1, 0.1≤y≤1, 0.1≤z≤1;

   Preferably, the x is 1, the y is 1, and the z is 1;

   Preferably, the chemical formula of the fluorinated oxalate material is KFeC ₂ O ₄ F, KCoC ₂ O ₄ F, KTiC ₂ O ₄ F, KVC ₂ O ₄ F, KMnC ₂ O ₄ F, KNiC ₂ O ₄ F, KCuC ₂ O ₄ F, KCo _0.5 V _0.5 C ₂ O ₄ F, KCu _0.9 Ti _0.1 C ₂ O ₄ F, KCo _0.5 Ni _0.5 C ₂ O ₄ F, KFe _0.7 Ni _0.3 C ₂ O ₄ F, KFe _1/3 At least one of Co _1/3 Ni _1/3 C ₂ O ₄ F, KCo _0.2 Ni _0.3 Mn _0.5 C ₂ O ₄ F or KFe _0.25 Co _0.25 Ni _0.25 Mn _0.25 C ₂ O ₄ F;

   Preferably, the chemical formula of the fluorinated oxalate material is KFeC ₂ O ₄ F, which belongs to an orthogonal system, the space group is Cmc2 ₁ , the decomposition temperature is 300° C., and the unit cell parameter is

   

   α=β=γ=90°;

   Preferably, the chemical formula of the fluorinated oxalate material is KMnC ₂ O ₄ F, which belongs to an orthogonal system, the space group is Cmc2 ₁ , the decomposition temperature is 305°C, and the unit cell parameter is

   

   α=β=γ=90°;

   Preferably, the chemical formula of the fluorinated oxalate material is KCoC ₂ O ₄ F, which belongs to an orthogonal system, the space group is Pmc2 ₁ , the decomposition temperature is 330° C., and the unit cell parameter is

   

   α=β=γ=90°;

   Preferably, preferably, the chemical formula of the fluorinated oxalate material is KNiC ₂ O ₄ F, which belongs to an orthogonal system, the space group is Pmc2 ₁ , the decomposition temperature is 325° C., and the unit cell parameter is

   

   α=β=γ=90°;

   Preferably, a potassium source, a transition metal source, an oxalate source, a fluorine source and an optional solvent are mixed to perform a solvothermal reaction to obtain the fluorinated oxalate material;

   Preferably, the molar ratio of the transition metal source, potassium source, oxalate source and fluorine source is 1: (2-8): (2-8): (2-8);

   Preferably, the potassium source includes at least one of potassium-containing oxides, acids, bases or salts;

   Preferably, the transition metal source includes a transition metal titanium source, a transition metal vanadium source, a transition metal chromium source, a transition metal manganese source, a transition metal iron source, a transition metal cobalt source, a transition metal nickel source, a transition metal copper source and a transition metal At least one of metal zinc sources;

   Preferably, the transition metal source includes at least one of oxides, hydroxides, halides, acids, bases, salts or transition metal elements containing transition metals;

   Preferably, the oxalate source includes at least one of oxalate-containing acid or salt;

   Preferably, the fluorine source includes at least one of fluorine-containing acid, alkali or salt;

   Preferably, the solvent includes at least one of water, alcohols, ketones or pyridines, preferably water;

   Preferably, the temperature of the solvothermal reaction is 140-250°C, preferably 190-200°C;

   And/or, the solvothermal reaction time is ≥24h, preferably 72-120h;

   Preferably, the solvothermal reaction further includes steps of separation, washing and drying;

   Preferably, the drying temperature is 40 to 120° C., the pressure is ≤20 kPa, and the time is 10 to 24 h.
6. The positive electrode material for a potassium ion battery according to claim 4 or 5, wherein the positive electrode material comprises 60 to 90 wt% of a positive electrode active material, 5 to 30 wt% of a conductive agent, and 5 to 10 wt% of a binder;

   Preferably, the conductive agent includes at least one of conductive carbon black, conductive carbon spheres, conductive graphite, carbon nanotubes, carbon fiber, graphene or reduced graphene oxide;

   Preferably, the binder includes at least one of polyvinylidene fluoride, polytetrafluoroethylene, polyvinyl alcohol, carboxymethyl cellulose, SBR rubber, or polyolefin-based binder.
7. A positive electrode for a potassium ion battery, characterized by comprising a positive electrode current collector and the positive electrode material for a potassium ion battery according to any one of claims 4 to 6;

   Preferably, the cathode current collector is any metal of aluminum, copper, iron, tin, zinc, nickel, titanium, or manganese; or, the cathode current collector is at least aluminum, copper, iron, tin, zinc , Nickel, titanium, or manganese; or, the positive electrode current collector is a metal composite material containing at least any one of aluminum, copper, iron, tin, zinc, nickel, titanium, or manganese.
8. A potassium ion battery, characterized in that it includes a negative electrode, a positive electrode, a separator between the positive and negative electrodes, and an electrolyte;

   The positive electrode is the positive electrode of the potassium ion battery of claim 7.
9. The method for preparing a potassium ion battery according to claim 8, wherein the negative electrode, the electrolyte, the separator, and the positive electrode are assembled to obtain a potassium ion battery.
10. The use of the potassium ion battery of claim 8 in an energy storage system or an electric device.

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