WO2023108501A1 - Calcium salt electrolyte solution and electrolyte, preparation method therefor and application thereof - Google Patents

Abstract

The present invention relates to the technical field of secondary batteries, and in particular, to a calcium salt electrolyte solution and an electrolyte, a preparation method therefor and an application thereof. The calcium salt electrolyte solution is obtained by completely reacting an organic solvent, metal calcium and a salt containing cations capable of being reduced by the metal calcium in the same container under the protection of inert gas, and the calcium salt electrolyte is obtained by removing the organic solvent in the prepared calcium salt electrolyte solution, or reducing the solubility of the calcium salt in the organic solvent, and separating out a calcium salt solute. According to the preparation method, the raw materials are cheap and easy to obtain, the time is short, the efficiency is high, the reaction is thorough, the purity is high, and the by-product is easy to separate and recover. Moreover, the purity of the prepared calcium salt electrolyte solution and the electrolyte is high, and the problem that the calcium salt electrolyte and the electrolyte solution required by the calcium ion battery are difficult to obtain is effectively solved.

Description

Calcium salt electrolytic solution and electrolyte, preparation method and application thereof technical field

The invention relates to the technical field of secondary batteries, in particular to a calcium salt electrolytic solution and electrolyte, a preparation method and application thereof.

Background technique

Energy storage technology is an important link in the application of renewable new energy. Lithium-ion batteries with high performance have been widely used in mobile electronic devices, electric vehicles, large-scale energy storage and other fields. However, the global reserves of lithium are only 14 million tons and the geographical distribution is uneven, making it difficult to support future energy storage needs. Therefore, it is of great significance to develop new energy storage systems, such as calcium ions and other energy storage systems.

Calcium ranks fifth in the crustal abundance, about 2,500 times that of lithium, and is not affected by geopolitics. As a divalent ion, calcium ions can react to generate twice as much charge as lithium ions per mole. For this reason, calcium-ion batteries are expected to become a new generation of high-performance, low-cost energy storage technology to fill the energy storage gap.

In secondary batteries, the electrolyte, as one of the main components of the battery, greatly affects the performance of the battery. Generally, the electrolyte solution of a secondary battery is composed of an organic solvent, an electrolyte (solute), additives, etc., wherein the electrolyte is the most critical component. Electrolytes can be classified according to the type of anion, such as hexafluorophosphate, tetrafluoroborate, perchlorate, etc. At present, electrolytes such as lithium salts, sodium salts, and potassium salts such as hexafluorophosphoric acid, tetrafluoroboric acid, and perchloric acid have perfect industrial production methods. The corresponding magnesium salts are also relatively mature. However, the development of corresponding calcium salts is slow, and there is a lack of efficient and safe production methods.

Take calcium hexafluorophosphate as an example. At present, lithium hexafluorophosphate, sodium hexafluorophosphate, potassium hexafluorophosphate and other electrolytes have perfect industrial production methods. Magnesium, which belongs to alkaline earth metals like calcium, has also reported the synthesis method of hexafluorophosphate electrolyte. However, calcium hexafluorophosphate electrolyte and electrolytes are still difficult to obtain. The standard route for the industrial production of alkali metal hexafluorophosphate uses anhydrous hydrofluoric acid (HF) as the medium to react phosphorus pentafluoride (PF ₅ ) with metal fluorides (LiF, NaF, KF) in the medium to form the corresponding hexafluorophosphate Fluorophosphate, however, this method cannot synthesize calcium hexafluorophosphate. Document J.Solid State Chem.2008,181,2318 uses CaF ₂ to react with PF ₅ in anhydrous hydrofluoric acid, and the product is Ca(HF ₂ ) ₂ . In addition, it was found that Ca(HF ₂ ) ₂ can also be directly obtained from CaF ₂ and anhydrous hydrofluoric acid, indicating that PF ₅ cannot effectively react with CaF ₂ in this route. Document Inorg.Chem.2006,45,1038 uses xenon difluoride (XeF ₂ ) to react with CaF ₂ and PF ₅ in anhydrous hydrofluoric acid to obtain [Ca(XeF ₂ ) ₅ ](PF ₆ ) ₂ product , XeF ₂ is a very strong oxidizing ligand, during the process of removing the XeF ₂ ligand, the product decomposes into CaF ₂ . Document J.Am.Chem.Soc.2016,138,8682 uses acetonitrile as a medium to react nitrosohexafluorophosphate (NOPF ₆ ) with metal magnesium, and separate the product to obtain Mg(PF ₆ ) ₂ (CH ₃ CN) ₆ electrolytes. Subsequently, the literature Chem.Commun.2017, 53, 4573 intends to use the above method to prepare calcium hexafluorophosphate electrolyte by reacting NOPF ₆ with metallic calcium. However, experiments have shown that this method results in the oxidative decomposition of hexafluorophosphate ions to generate difluorophosphate ions (PO ₂ F ₂ ⁻ ). The synthesis method of calcium hexafluorophosphate (Ca(PF ₆ ) ₂ ) reported in the literature Chem.Mater.2015,27,844 uses silver hexafluorophosphate (AgPF ₆ ) and anhydrous calcium chloride (CaCl ₂ ) as reactants, in acetonitrile solvent Metathesis reaction occurs in , and Ca(PF ₆ ) ₂ and silver chloride (AgCl) are predicted to be generated. There are obvious defects in this method: firstly, the reaction conversion rate depends on the solubility difference of _CaCl and AgCl, because both are insoluble substances, the reaction conversion rate is small, the impurity content is high, and the purification cost is high; secondly, because the reaction generates AgCl as The solid-phase product will adhere to the surface of the reactant, further slowing down the reaction rate and reducing the reaction conversion rate; moreover, the noble metal precursor AgPF ₆ will bring extremely high production costs, which cannot meet industrial applications.

Take calcium perchlorate as an example. The industrial preparation method of calcium perchlorate is to react calcium nitrate or calcium chloride with perchloric acid solution, then evaporate and cool the solution to obtain calcium perchlorate tetrahydrate, and then decompress and heat to obtain calcium perchlorate . The decompression and heating process are relatively complicated. On the one hand, it is difficult to completely remove the crystal water, resulting in impure products. On the other hand, improper control of the heating process can easily cause explosions. The Chinese patent with application number 201910551846 discloses a calcium perchlorate preparation device and method. However, the patent only provides a preparation method for calcium perchlorate solution, and includes from the primary electro-oxidation unit to the secondary electro-oxidation unit to the The three-stage electro-oxidation unit has complex devices and cumbersome preparation process. The literature Dalton Transactions, 2010, 32 (40), 9696 reports calcium salt perchlorate in benzonitrile solvent, yet the obtained solid product contains inseparable organic solvent molecules and surrounds calcium ions. The perchlorate calcium salt reported in the literature Russian Journal of General Chemistry 2004,74,1150 and Z.Anorg.Allg.Chem.2004,630,914 not only contains organic solvent molecules, but also additionally contains water molecules. The presence of these organic solvent molecules and water molecules seriously affects its performance as an organic system electrolyte, related electrolytes and calcium ion energy storage devices.

In view of this, the present invention is proposed.

Contents of the invention

In order to overcome the above-mentioned technical problems, the present invention provides calcium salt electrolytes and electrolytes and their preparation methods and applications, aiming to solve various problems existing in the existing calcium salt electrolytes and electrolyte preparation methods, and to improve the performance of calcium ion batteries .

In a first aspect, the present invention provides a method for preparing a calcium salt electrolyte, comprising the following steps:

The organic solvent, metallic calcium and a salt containing cations that can be reduced by metallic calcium are placed in the same container, and reacted completely under the protection of an inert gas to obtain a calcium salt electrolyte.

Preferably, the salt comprising a cation reducible by metallic calcium is cuprous or ammonium tetraacetonitrile.

Preferably, said salt comprising a cation reducible by metallic calcium also comprises a stabilizing anionic group;

The anion group is hexafluorophosphate, tetrafluoroborate, perchlorate, bisfluorosulfonamide, bis(trifluoromethylsulfonyl)imide, trifluoromethylsulfonate, perfluoroalkyl Any one of sulfonate, fluorosulfonate, chlorosulfonate, carborane cluster, and tetrakis(hexafluoroisopropyl)borate.

Preferably, the amount of calcium metal is excessive to ensure the purity of the product and shorten the reaction time;

When the salt containing cations that can be reduced by metal calcium is tetraacetonitrile cuprous salt or ammonium salt, the amount of the metal calcium substance is not less than half of tetraacetonitrile cuprous salt or ammonium salt.

Preferably, the organic solvent includes one or more of esters, sulfones, ethers, nitrile organic solvents or ionic liquids.

Preferably, the organic solvent comprises propylene carbonate (PC), ethylene carbonate (EC), diethyl carbonate (DEC), dimethyl carbonate (DMC), ethyl methyl carbonate (EMC), acetonitrile (ACN) , methyl formate (MF), methyl acetate (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 (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-bistrifluoroborate Fluoromethylsulfonylimide salt, 1-propyl-3-methylimidazole-hexafluorophosphate, 1-propyl-3-methylimidazole-tetrafluoroborate, 1-propyl-3-methyl Imidazole-bistrifluoromethanesulfonimide salt, 1-butyl-1-methylimidazole-hexafluorophosphate, 1-butyl-1-methylimidazole-tetrafluoroborate, 1-butyl Base-1-methylimidazole-bistrifluoromethylsulfonimide salt, N-butyl-N-methylpyrrolidine-bistrifluoromethylsulfonimide salt, 1-butyl-1-methyl N-methyl-N-propylpyrrolidine-bistrifluoromethylsulfonimide salt, N-methyl-N-propylpyrrolidine-bistrifluoromethylsulfonimide salt, N-methyl,propylpiperidine-bistrifluoromethylsulfonimide One or more of methylsulfonimide salt, N-methyl, butylpiperidine-bistrifluoromethylsulfonimide salt.

In a second aspect, the present invention provides a method for preparing a calcium salt electrolyte, comprising the following steps:

The calcium salt electrolyte is prepared by the method for preparing the calcium salt electrolyte as described above;

The organic solvent is then removed, or the solubility of the calcium salt in the organic solvent is reduced to precipitate the calcium salt solute.

In the third aspect, the present invention also provides a calcium salt electrolyte, which is prepared by the above-mentioned preparation method of the calcium salt electrolyte.

In the fourth aspect, the present invention also provides a calcium salt electrolyte, which is prepared by the above-mentioned preparation method of the calcium salt electrolyte;

Alternatively, the above-mentioned calcium salt electrolyte can be redissolved in other organic solvents.

In the fifth aspect, the present invention also provides a calcium-ion battery, including a negative electrode of the battery, an electrolyte, a diaphragm, and a positive electrode of the battery, and the electrolyte is the above-mentioned calcium salt electrolyte.

In a sixth aspect, the present invention also provides an energy storage device, including the above-mentioned calcium ion battery.

In the seventh aspect, the present invention also provides an electrical device, including the above-mentioned calcium-ion battery.

Compared with prior art, the beneficial effect of the present invention is:

(1) The preparation method of the calcium salt electrolyte and electrolyte solution of the present invention solves the existing problems such as complex synthesis routes, high cost, low efficiency, and low product purity. For example, regarding the preparation method and products of calcium hexafluorophosphate electrolyte and electrolyte solution, the use of highly toxic and highly corrosive raw materials such as HF and PF ₅ in the industry is avoided, and the process is safer, more environmentally friendly, and more operable. The use of commercially available cheap metal calcium and cuprous tetraacetonitrile or ammonium salt as raw materials avoids the use of expensive precursors, and the cost is low. The by-products of the reaction are metal copper or ammonia and hydrogen, which are of high purity, easy to separate, and have recycling value. The preparation method has the advantages of short time, high efficiency, thorough reaction and high purity.

(2) The calcium salt electrolyte of the present invention has high purity, good chemical stability, good compatibility with conventional electrode materials, and high ion conductivity and ion mobility.

(3) The calcium salt electrolyte of the present invention has high purity and high solubility in conventional organic solvents. The electrolyte solution obtained after the electrolyte is dissolved has a high concentration, good chemical stability, good compatibility with conventional electrode materials, and high ion conductivity and ion mobility.

(4) Calcium ion battery, energy storage equipment and electrical equipment of the present invention, comprise above-mentioned electrolytic solution or electrolyte, all have higher operating voltage and capacity.

Description of drawings

Fig. 1 is the ¹⁹ F and ³¹ P nuclear magnetic resonance (NMR) spectra of the calcium hexafluorophosphate electrolyte prepared by embodiment 1;

Fig. 2 is the powder X-ray diffraction (XRD) spectrum of reaction by-product in embodiment 1;

Fig. 3 is the energy dispersive X-ray (EDX) spectrum of the calcium hexafluorophosphate electrolyte prepared by embodiment 2;

Fig. 4 is the ¹ H nuclear magnetic resonance (NMR) spectrum of the calcium hexafluorophosphate electrolyte prepared by embodiment 3;

Fig. 5 is the constant current charge and discharge curve figure of the calcium ion battery prepared by embodiment 5;

Fig. 6 is the structural representation of a kind of calcium ion battery provided by the present invention;

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

Detailed ways

The present invention will be described in further detail below in conjunction with the accompanying drawings and specific embodiments. The following description is a preferred embodiment of the present invention. It should be pointed out that for those skilled in the art, some improvements and modifications can be made without departing from the principles of the embodiments of the present invention. These improvements and modifications It is also regarded as the protection scope of the present invention.

It should be noted:

In the present invention, if there is no special description, all the implementation methods and preferred methods mentioned herein can be combined with each other to form a new technical solution.

In the present invention, if there is no special description, all the technical features and preferred features mentioned herein can be combined with each other to form a new technical solution.

In the present invention, unless otherwise specified, the various components involved or their preferred components can be combined with each other to form a new technical solution.

The "range" disclosed in the present invention takes the form of lower limit and upper limit, and may respectively have one or more lower limits, and one or more upper limits.

In the present invention, unless otherwise specified, each reaction or operation step may be performed sequentially or not. Preferably, the methods herein are performed sequentially.

Unless otherwise specified, professional and scientific terms used herein have the same meanings as those familiar to those skilled in the art. In addition, any method or material similar or equivalent to the content described can also be applied in the present invention.

In the first aspect, the present invention provides a method for preparing a calcium salt electrolyte, comprising the following steps: placing an organic solvent, a salt containing a stable anionic group, and metal calcium in the same container under the protection of an inert gas, and waiting for the reaction to complete , to obtain calcium salt electrolyte. Among them, the salts containing stable anionic groups contain cations that can be reduced by metallic calcium. Preferably, the cations are tetraacetonitrile cuprous ions and ammonium ions, and the reduction products are metal copper, ammonia and hydrogen. Preferably, the amount of calcium metal should not be less than one-half of that of tetraacetonitrile cuprous ion salt and ammonium ion salt.

The method avoids the use of highly toxic and highly corrosive raw materials such as HF and PF ₅ , and the process is safer, more environmentally friendly, and more operable, and solves the difficult problem of calcium salt electrolyte and electrolyte solution being difficult to obtain. The use of commercially available cheap metal calcium and cuprous tetraacetonitrile or ammonium salt as raw materials avoids the use of expensive precursors, and the cost is low. The by-products of the reaction are metal copper or ammonia and hydrogen, which are of high purity, easy to separate, and have recycling value. The preparation method has the advantages of short time, high efficiency, thorough reaction and high purity.

The organic solvent is not particularly limited, and may be 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), acetonitrile (ACN), methyl formate (MF), methyl acetate (MA), N,N-dimethylacetamide (DMA), fluoroethylene carbonate (FEC), methyl propionate (MP), ethyl propionate (EP), acetic acid Ethyl ester (EA), γ-butyrolactone (GBL), tetrahydrofuran (THF), 2-methyltetrahydrofuran (2MeTHF), 1,3-dioxolane (DOL), 4-methyl-1,3 -Dioxolane (4MeDOL), dimethoxymethane (DMM), 1,2-dimethoxypropane (DMP), triethylene glycol dimethyl ether (DG), dimethyl sulfone (MSM), di Methyl 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-bistrifluoromethylsulfonate imide salt, 1-propyl-3-methylimidazole-hexafluorophosphate, 1-propyl-3-methylimidazole-tetrafluoroborate, 1-propyl-3-methylimidazole-bis Trifluoromethanesulfonimide salt, 1-butyl-1-methylimidazole-hexafluorophosphate, 1-butyl-1-methylimidazole-tetrafluoroborate, 1-butyl-1- Methylimidazole-bistrifluoromethylsulfonimide salt, N-butyl-N-methylpyrrolidine-bistrifluoromethylsulfonimide salt, 1-butyl-1-methylpyrrolidine- Bistrifluoromethylsulfonimide salt, N-methyl-N-propylpyrrolidine-bistrifluoromethylsulfonimide salt, N-methyl,propylpiperidine-bistrifluoromethylsulfonyl One or more of imide salts, N-methyl, butylpiperidine-bistrifluoromethylsulfonimide salts.

In a second aspect, the present invention also provides a method for preparing a calcium salt electrolyte, comprising the following steps: removing the organic solvent from the calcium salt electrolyte prepared by the above method; or reducing the solubility of the calcium salt in the solvent to obtain calcium salt electrolyte.

The method for removing the organic solvent is not particularly limited. Specifically, methods such as heating evaporation, reduced pressure evaporation, and normal temperature evaporation can be used.

The method for reducing the solubility of the calcium salt in the solvent is not particularly limited. Specifically, methods such as freezing, passing through weak polar or non-polar solvents, and the like can be used.

In the third aspect, the present invention also provides a calcium salt electrolyte obtained by the above preparation method of the calcium salt electrolyte. The electrolyte is of high purity and has high solubility in conventional organic solvents. The electrolyte solution obtained after the electrolyte is dissolved has a high concentration, good chemical stability, good compatibility with conventional electrode materials, and high ion conductivity and ion mobility.

In the fourth aspect, the present invention also provides a calcium salt electrolyte obtained by the above preparation method of the calcium salt electrolyte. Alternatively, it can be obtained by redissolving the above calcium salt electrolyte in other organic solvents. The calcium salt electrolyte has high purity, good chemical stability, good compatibility with conventional electrode materials, and high ion conductivity and ion mobility.

In the fifth aspect, the present invention also provides a calcium-ion battery, including a positive electrode, a separator, a negative electrode and the above-mentioned calcium salt electrolyte. The calcium-ion battery has a relatively high working voltage and capacity.

The calcium ion battery provided by the present invention has two working principles, one is: during the charging process, calcium ions are desorbed or desorbed from the positive electrode and enter the electrolyte, and the calcium ions in the electrolyte migrate to the negative electrode and intercalate or absorb In the negative electrode active material; during the discharge process, calcium ions either desorb or desorb from the negative electrode material and enter the electrolyte, and the calcium ions in the electrolyte migrate to the positive electrode and intercalate or adsorb in the positive electrode active material. The second is: during the charging process, the anions in the electrolyte migrate to the positive electrode and embed or adsorb in the positive active material, and the calcium ions in the electrolyte migrate to the negative electrode and embed or adsorb in the negative active material; during the discharge process, the anions from the positive electrode Desorb or desorb and enter the electrolyte, calcium ions desorb or desorb from the negative electrode and enter the electrolyte.

positive electrode

The positive electrode includes a positive electrode active material layer and a positive electrode current collector, the positive electrode active material layer includes a positive electrode active material, a positive electrode conductor and a positive electrode binder, the content of the positive electrode active material is 50-99wt%, and the content of the positive electrode conductor is 0.5-30wt%, the content of positive electrode binder is 0.5-20wt%.

Preferably, the positive electrode active material includes at least one of carbon materials, organic substances, metals, alloys, oxides, sulfides, nitrides or carbides.

negative electrode

The negative electrode includes a negative electrode active material layer and a negative electrode current collector, the negative electrode active material layer includes a negative electrode active material, a negative electrode conductive agent and a negative electrode binder, the content of the negative electrode active material is 50-99wt%, and the content of the negative electrode conductive agent is 0.5-30wt%, the content of the negative electrode binder is 0.5-20wt%.

Preferably, the negative electrode active material includes at least one of carbon materials, organic substances, metals, alloys, oxides, sulfides, nitrides or carbides.

Wherein, the positive electrode conductive agent or the negative electrode conductive agent includes at least one of conductive carbon black, conductive carbon spheres, conductive graphite, carbon nanotubes, conductive carbon fibers, graphene or reduced graphene oxide.

The positive electrode binder or negative electrode binder includes at least one of polyvinylidene fluoride, polytetrafluoroethylene, polyvinyl alcohol, carboxymethyl cellulose, SBR rubber (Styrene Butadiene Rubber, styrene-butadiene rubber) or polyolefins .

The positive or negative current collector is any one of aluminum, copper, iron, tin, zinc, nickel, titanium, manganese, lead, antimony, cadmium, gold, bismuth or germanium; or, the positive or negative current collector It is an alloy including at least any one of aluminum, copper, iron, tin, zinc, nickel, titanium, manganese, lead, antimony, cadmium, gold, bismuth or germanium; or, the positive electrode collector or the negative electrode collector is at least including A composite material of any one of aluminum, copper, iron, tin, zinc, nickel, titanium, manganese, lead, antimony, cadmium, gold, bismuth or germanium; or, the positive current collector or negative current collector is a carbon material.

"Alloy" refers to a substance with metallic properties synthesized by two or more metals and metals or nonmetals by a certain method.

"Metal composite material" refers to a metal-based composite conductive material formed by combining metal and other non-metallic materials. Typical but non-limiting metal composites include graphene-metal composites, carbon fiber-metal composites, ceramic-metal composites, and the like.

Electrolyte

The electrolytic solution includes the above-mentioned calcium salt electrolytic solution.

In some embodiments, the electrolyte solution further includes additives, and the content of the additives is preferably 0.1-20 wt%. The additive is added in the electrolyte, and the additive can form a stable solid electrolyte film on the surface of the electrode and improve the service life of the battery.

The additives include at least one of esters, sulfones, ethers, nitriles or olefins.

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, metadiazepine, crown ether 12-crown-4, crown ether 18-crown-6, 4-fluoroanisole, fluorinated chain ether, difluoromethylethylene carbonate, Trifluoromethylethylene carbonate, chloroethylene carbonate, bromoethylene carbonate, trifluoroethylphosphonic acid, bromobutyrolactone, fluoroacetoxyethane, phosphate, phosphite, phosphazene , ethanolamine, carbodimethylamine, cyclobutylsulfone, 1,3-dioxolane, acetonitrile, long-chain olefins, aluminum oxide, magnesium oxide, barium oxide, sodium carbonate, calcium carbonate, carbon dioxide, sulfur dioxide or at least one of lithium carbonate.

diaphragm

The diaphragm includes porous polymer film or inorganic porous film, preferably at least one of porous polypropylene film, porous polyethylene film, porous composite polymer film, glass fiber paper or porous ceramic diaphragm.

The structure of a calcium ion battery provided by the present invention, as shown in FIG. 6 , includes a negative electrode current collector 1 , a negative electrode active material layer 2 , a separator 3 , an electrolyte 4 , a positive electrode active material layer 5 and a positive electrode current collector 6 .

Exemplarily, the preparation method of the calcium ion battery includes: assembling the positive electrode, the separator, the negative electrode and the electrolyte. The above preparation method has simple process and low manufacturing cost, and the calcium ion battery prepared by the method has the advantages of high discharge voltage and high charge and discharge capacity.

Preferably, the preparation method of calcium ion battery comprises the following steps:

(a) Preparing the positive electrode: making the positive electrode slurry from the positive electrode active material, the positive electrode conductive agent and the positive electrode binder, and then coating the positive electrode slurry on the surface of the positive electrode current collector, drying and cutting to obtain a positive electrode of the desired size; or , press the positive electrode active material on the surface of the positive electrode current collector, and obtain the negative electrode with the required size after cutting;

(b) preparing the negative electrode: making the negative electrode slurry from the negative electrode active material, the negative electrode conductive agent and the negative electrode binder, and then coating the negative electrode slurry on the surface of the negative electrode current collector, drying and cutting to obtain the negative electrode of the required size; or , press the negative electrode active material on the surface of the negative electrode current collector, and obtain the negative electrode with the required size after cutting;

(c) Electrolyte preparation: the electrolyte prepared by the above method for preparing the calcium salt electrolyte, or the electrolyte prepared by dissolving the electrolyte prepared by the above method for preparing the calcium salt electrolyte in an organic solvent;

(d) Preparing the diaphragm: cutting the porous polymer film or inorganic porous film of the required size for later use;

Assemble the positive electrode obtained in step (a), the negative electrode obtained in step (b), the electrolyte obtained in step (c), and the separator obtained in step (d).

Preferably, the assembly process is as follows: in an inert atmosphere or a dry environment, the prepared positive electrode, separator, and negative electrode are tightly stacked or wound in sequence, and the electrolyte is dripped to completely infiltrate the separator, and then packaged into the case to complete the calcium ion process. Assembly of the battery.

In addition, the form of the calcium-ion battery of the present invention is not limited to button batteries, and can also be designed into square shells, cylinders, soft packs, etc. according to the core components.

In a sixth aspect, the present invention also provides an energy storage device comprising the calcium-ion battery described above, thus having at least the same advantages as the calcium-ion battery described above, and having a higher working voltage and capacity.

The above-mentioned energy storage devices refer to power storage devices that mainly use calcium-ion batteries as power storage sources, including but not limited to household energy storage systems or distributed energy storage systems. For example, in a home energy storage system, electric power is stored in a calcium ion battery serving as a power storage source, and as needed, the electric power stored in the calcium ion battery is consumed to enable use of various devices such as home appliances.

In the seventh aspect, the present invention also provides an electrical device, including the above-mentioned calcium-ion battery, thus having at least the same advantages as the above-mentioned calcium-ion battery, and having a higher working voltage and capacity.

The aforementioned electrical equipment includes but is not limited to electronic products, electric tools, or electric vehicles. Electronic products are electronic devices that perform various functions, such as playing music, using a calcium-ion battery as an operating power source. A power tool is an electric tool that uses a calcium-ion battery as a driving power source for moving parts such as a drill. Electric vehicles are electric vehicles (including electric bicycles, electric cars) that run on calcium ion batteries as a driving power source, and may be automobiles equipped with other driving sources in addition to calcium ion batteries, including hybrid vehicles.

Below in conjunction with embodiment and comparative example the present invention is described in further detail.

Example 1

Calcium hexafluorophosphate electrolyte, its preparation process is as follows:

In an argon atmosphere, 4.472 g of tetraacetonitrile cuprous hexafluorophosphate and 0.481 g of calcium metal were placed in 30 ml of anhydrous acetonitrile; after stirring for 10 hours, the calcium hexafluorophosphate electrolyte was obtained by filtration.

The obtained calcium hexafluorophosphate electrolyte was characterized by nuclear magnetic resonance (NMR) of ¹⁹ F and ³¹ P, and the results are shown in Figure 1, ¹⁹ F shows a doublet, and ³¹ P shows a septet, which are PF ₆ ^-ions . Characteristic lines. No other peak shapes of ¹⁹ F and ³¹ P were seen, indicating that PF ₆ ^- is a single species of F and P elements, and PF ₆ ^- ion does not decompose.

Get and filter gained reaction by-product, carry out powder X-ray diffraction (XRD) characterization, the result is as shown in Figure 2, and reaction reduction product is metal copper, and Ca(OH) ₂ originate from metal calcium raw material, because Ca(OH) ₂ in organic It does not dissolve in the solvent and does not pollute the prepared electrolyte.

Example 2

Calcium hexafluorophosphate electrolyte, the preparation process is as follows:

The calcium hexafluorophosphate electrolyte prepared in Example 1 was taken and vacuum-dried for 24 hours to obtain the calcium hexafluorophosphate electrolyte.

The obtained calcium hexafluorophosphate electrolyte was characterized by energy dispersive X-ray spectroscopy (EDX). The results are shown in Figure 3. Only calcium, phosphorus, and fluorine element signals were seen, but no copper element signal was seen, indicating that the reaction was complete and the product was of high purity.

Example 3

Calcium hexafluorophosphate electrolyte, the preparation process is as follows:

In an argon atmosphere, put 2.445 grams of ammonium hexafluorophosphate and 0.601 grams of calcium metal in 30 ml of anhydrous acetonitrile; after stirring for 10 hours, filter to obtain a clear solution; degas the clear solution to obtain hexafluoro Calcium phosphate electrolyte.

The obtained calcium hexafluorophosphate electrolyte was subjected to ¹ H nuclear magnetic resonance (NMR) characterization, and the results are shown in Figure 4. No characteristic signal of ammonium cations was seen, indicating that the reaction was complete and the product was of high purity.

Example 4

Calcium hexafluorophosphate electrolyte, the preparation process is as follows:

The calcium hexafluorophosphate electrolyte prepared in Example 3 was taken and vacuum-dried for 24 hours to obtain the calcium hexafluorophosphate electrolyte.

Example 5

A calcium ion battery, its preparation process is as follows:

(1) Preparation of battery negative electrode: Mesocarbon microspheres MCMB, conductive carbon black, and polyvinylidene fluoride PVDF were adjusted to a uniform slurry with N-methylpyrrolidone NMP at a mass ratio of 8:1:1. The slurry was uniformly coated on the surface of aluminum foil (negative electrode current collector), and dried in vacuum. The battery pole piece obtained by drying was cut into discs with a diameter of 12 mm, and after compaction, it was used as a battery negative electrode for future use.

(2) Preparation of battery positive electrode: adjust expanded graphite, conductive carbon black, and polyvinylidene fluoride PVDF with NMP at a mass ratio of 8:1:1 to form a uniform slurry. The slurry was evenly coated on the surface of the aluminum foil (positive current collector), and dried in vacuum. Cut the dried battery pole piece into a disc with a diameter of 10mm, and compact it as a battery positive electrode for future use.

(3) Preparation of the separator: the glass fiber film was cut into discs with a diameter of 16 mm and used as the separator for later use.

(4) Battery assembly: In an argon atmosphere glove box, the above-mentioned prepared negative pole pieces, diaphragms, and positive pole pieces are closely stacked in sequence, and the calcium salt electrolyte prepared in Example 1 is added dropwise to completely infiltrate the diaphragm, and then the The above-mentioned stacked parts are packaged into the button battery casing to complete the assembly of the double carbon calcium ion battery.

The constant current charge and discharge curve of the battery is shown in Figure 5. The charge specific capacity of the calcium ion battery is 67.3mAh/g, and the discharge specific capacity is 55.5mAh/g.

Example 6

A calcium ion battery, the difference from Example 5 is that the electrolyte used is: the calcium hexafluorophosphate electrolyte prepared in Example 2 is dissolved in EC+PC+DMC+EMC (volume ratio is 2:2:3 :3) in, make the calcium hexafluorophosphate electrolyte that concentration is 0.6mol/L. The rest are the same as in Embodiment 5, and will not be repeated here.

Example 7-66

Embodiment 7-66 provides the method for preparing calcium hexafluorophosphate electrolyte and electrolyte, and the difference with embodiment 1-2 is, the quality of tetraacetonitrile cuprous hexafluorophosphate used, the quality of metal calcium, the kind of organic solvent , reaction time, and electrolyte preparation methods are different, as shown in Table 1.

The process parameter table of preparing calcium hexafluorophosphate electrolyte and electrolyte in the embodiment 7-66 of table 1

Examples 67-126

Embodiment 67-126 provides the method for preparing calcium hexafluorophosphate electrolyte and electrolyte, and the difference from embodiment 3-4 is that the quality of ammonium hexafluorophosphate used, the quality of metallic calcium, the type of organic solvent, the length of reaction, the electrolyte The preparation methods are different, as shown in Table 2.

The process parameter table of the calcium hexafluorophosphate electrolyte and electrolyte of table 2 embodiment 67-126

Examples 127-146

Examples 127-146 respectively provide calcium tetrafluoroborate, calcium perchlorate, calcium bisfluorosulfonyl imide, calcium bis(trifluoromethylsulfonyl)imide, calcium trifluoromethanesulfonate, perfluoroalkane Calcium sulfonate, calcium fluorosulfonate, calcium chlorosulfonate, carborane cluster calcium, tetrakis(hexafluoroisopropyl)calcium borate electrolyte and preparation method of electrolyte solution.

The difference between Examples 127-136 and Examples 1-2 is that the type of cuprous tetraacetonitrile used is different, and the amount of the substance is equal to that described in Example 1. The difference between Examples 137-146 and Examples 3-4 is that the types of ammonium salts used are different, and the amount of the substances is equal to that described in Example 3, see Table 3 for details.

The process parameter table of the calcium salt electrolyte of table 3 embodiment 127-146

Examples 147-196

Embodiment 147-196 provides the preparation method of calcium ion battery, and the difference with embodiment 5-6 is:

The electrolyte used in Examples 147-151 comes from the calcium hexafluorophosphate electrolyte obtained in Examples 7-11 respectively;

The electrolyte used in Examples 152-156 is the 0.8mol/L calcium hexafluorophosphate electrolyte prepared from the calcium hexafluorophosphate electrolyte obtained in Examples 7-11;

The electrolyte used in Examples 157-161 is the 0.6mol/L calcium hexafluorophosphate electrolyte prepared from the calcium hexafluorophosphate electrolyte obtained in Examples 7-11;

The electrolytes used in Examples 162-166 are respectively from the calcium hexafluorophosphate electrolytes obtained in Examples 67-71;

The electrolyte used in Examples 167-171 is the 0.8mol/L calcium hexafluorophosphate electrolyte prepared from the calcium hexafluorophosphate electrolyte obtained in Examples 67-71;

The electrolytes used in Examples 172-176 were 0.6 mol/L calcium hexafluorophosphate electrolytes prepared from the calcium hexafluorophosphate electrolytes obtained in Examples 67-71, respectively.

The electrolytes used in Examples 177-196 are 0.4 mol/L calcium salt electrolytes prepared from the calcium salt electrolytes obtained in Examples 127-146, respectively.

Examples 197-211

Examples 197-211 provide calcium-ion batteries and their preparation methods. The difference from Examples 5-6 lies in the use of different electrolytes and positive electrode active materials, as shown in Table 4.

The parameter table of the calcium ion battery of table 4 embodiment 157-171

Example	Electrolyte	Cathode material
197	Example 7	CaCo 2 O 4

198	Example 7	CaMn 2 O 4
199	Example 7	Ca 3 Co 2 O 6
200	Example 7	CaMoO 3
201	Example 67	Prussian blue analog
202	Example 67	S
203	Example 67	V 2 O 5
204	Example 67	Mo 3 S 4
205	Example 67	MnO2
206	Example 10	Prussian blue analog
207	Example 15	Prussian blue analog
208	Example 70	Prussian blue analog
209	Example 75	Prussian blue analog
210	Example 10	V 2 O 5
211	Example 70	V 2 O 5

Comparative example 1-4

The difference between Comparative Example 1-4 and Examples 1-2 and 5-6 is that the amount of tetraacetonitrile copper hexafluorophosphate used is 9 grams, and the anhydrous acetonitrile used is 60 milliliters, and the rest are the same as in Example 1-4, except Let me repeat.

Comparative example 5-6

The difference between Comparative Example 5-6 and Example 3-4 is that the amount of ammonium hexafluorophosphate used is 5 grams, the amount of anhydrous acetonitrile used is 60 ml, and the rest is the same as that of Example 1-2, and will not be repeated here.

Comparative example 7-8

The difference between Comparative Example 7-8 and Example 5-6 is that the electrolyte used is the electrolyte obtained in Comparative Example 5, the electrolyte used is the electrolyte obtained in Comparative Example 6, and the rest is the same as that of Example 5-6, and will not be repeated here.

Elemental analysis was carried out on the electrolytic solution and electrolyte prepared in Comparative Example 1-2, and the results showed that the cations in the sample not only included calcium element, but also copper element. The electrolytic solution and electrolyte prepared in Comparative Examples 5-6 were characterized by NMR, and the results showed that there were ammonium ions in the sample, indicating that the corresponding preparation method was not perfect, and the prepared electrolytic solution and electrolyte had low purity.

Constant current charge and discharge tests were performed on the calcium ion batteries of the above-mentioned Examples 5-6, Examples 147-176, Examples 197-201 and Comparative Examples 3-4, 7-8, and the test results are shown in Table 5.

Performance Testing

Constant current charge and discharge tests were carried out on the calcium ion batteries prepared in the above examples 5-6, 147-176, 197-201 and comparative examples 3-4 and 7-8, and the test results are shown in Table 6.

Table 6 embodiment 5-6, the calcium ion battery performance test result of embodiment 127-171 and comparative example 3-4, 7-8

Example	First cycle discharge specific capacity (mAh/g)	Stable discharge specific capacity (mAh/g)
Example 5	52.9	55.5
Example 6	58.7	57.3
Example 147	43.0	38.9
Example 148	57.5	41.7
Example 149	58.3	57.5
Example 150	43.2	41.1
Example 151	71.7	73.4
Example 152	71.0	71.9
Example 153	55.4	51.4
Example 154	67.4	68.1
Example 155	45.2	40.2
Example 156	61.7	49.3
Example 157	49.1	51.2
Example 158	55.6	39.6
Example 159	69.5	56.6
Example 160	46.9	48.8
Example 161	50.6	41.9
Example 162	56.9	46.0
Example 163	51.8	38.5
Example 164	67.9	69.3
Example 165	74.6	75.7
Example 166	45.6	37.2
Example 167	48.3	49.0
Example 168	64.6	56.5
Example 169	53.1	48.6
Example 170	74.1	69.0
Example 171	74.0	69.9
Example 172	62.5	44.4
Example 173	70.1	62.0

Example 174	54.1	38.5
Example 175	62.1	61.5
Example 176	74.5	61.0
Example 197	59.6	59.4
Example 198	72.7	57.1
Example 199	65.2	58.9
Example 200	56.9	58.5
Example 201	62.4	44.7
Example 202	71.1	51.1
Example 203	47.0	33.2
Example 204	53.8	50.5
Example 205	74.7	68.0
Example 206	54.1	40.0
Example 207	63.1	61.7
Example 208	71.5	65.6
Example 209	74.8	54.2
Example 210	62.9	45.5
Example 211	43.8	32.7
Comparative example 3	15.7	10.2
Comparative example 4	9.1	17.4
Comparative example 7	6.8	9.6
Comparative example 8	11.2	10.7

It can be seen from Table 6 that, compared with the calcium ion battery in the comparative example, the calcium ion battery of the embodiment of the present invention has significantly improved initial discharge specific capacity and stable discharge specific capacity. Among them, Examples 151-152, The calcium-ion battery in 170-171 has the highest initial discharge specific capacity and stable discharge specific capacity, and the best performance. Therefore, it also shows that Examples 151-152 and 170-171 can provide more effective methods for preparing calcium hexafluorophosphate electrolyte and electrolyte, and calcium ion batteries with better performance.

To sum up, compared with the prior art, the beneficial effects of the present invention are:

(1) The preparation method of the calcium salt electrolyte and electrolyte solution of the present invention solves the existing problems such as complex synthesis routes, high cost, low efficiency, and low product purity. For example, regarding the preparation method and products of calcium hexafluorophosphate electrolyte and electrolyte solution, the use of highly toxic and highly corrosive raw materials such as HF and PF ₅ in the industry is avoided, and the process is safer, more environmentally friendly, and more operable. The use of commercially available cheap metal calcium and cuprous tetraacetonitrile or ammonium salt as raw materials avoids the use of expensive precursors, and the cost is low. The by-products of the reaction are metal copper or ammonia and hydrogen, which are of high purity, easy to separate, and have recycling value. The preparation method has the advantages of short time, high efficiency, thorough reaction and high purity.

(2) The calcium salt electrolyte of the present invention has high purity, good chemical stability, good compatibility with conventional electrode materials, and high ion conductivity and ion mobility.

(3) The calcium salt electrolyte of the present invention has high purity and high solubility in conventional organic solvents. The electrolyte solution obtained after the electrolyte is dissolved has a high concentration, good chemical stability, good compatibility with conventional electrode materials, and high ion conductivity and ion mobility.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present invention, rather than limiting them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: It is still possible to modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the technical solutions of the various embodiments of the present invention. scope.

Claims (12)

1. A preparation method of calcium salt electrolyte, is characterized in that, comprises the following steps:

   The organic solvent, metallic calcium and a salt containing cations that can be reduced by metallic calcium are placed in the same container, and reacted completely under the protection of an inert gas to obtain a calcium salt electrolyte.
2. The preparation method of calcium salt electrolytic solution according to claim 1, characterized in that the salt comprising a cation that can be reduced by metal calcium is cuprous tetraacetonitrile or ammonium salt.
3. The preparation method of calcium salt electrolyte according to claim 1, characterized in that, the salt comprising a cation which can be reduced by metal calcium also comprises a stable anion group;

   The anion group is hexafluorophosphate, tetrafluoroborate, perchlorate, bisfluorosulfonamide, bis(trifluoromethylsulfonyl)imide, trifluoromethylsulfonate, perfluoroalkyl Any one of sulfonate, fluorosulfonate, chlorosulfonate, carborane cluster, and tetrakis(hexafluoroisopropyl)borate.
4. The preparation method of calcium salt electrolyte according to claim 1, wherein the consumption of the calcium metal is excessive, so as to ensure the purity of the product and shorten the reaction time;

   When the salt containing cations that can be reduced by metal calcium is tetraacetonitrile cuprous salt or ammonium salt, the amount of the metal calcium substance is not less than half of tetraacetonitrile cuprous salt or ammonium salt.
5. The preparation method of calcium salt electrolyte according to claim 1, wherein the organic solvent comprises one or more of esters, sulfones, ethers, nitrile organic solvents or ionic liquids.
6. The preparation method of calcium salt electrolyte according to claim 5, is characterized in that, described organic solvent comprises propylene carbonate (PC), ethylene carbonate (EC), diethyl carbonate (DEC), dimethyl carbonate (DMC), ethyl methyl carbonate (EMC), acetonitrile (ACN), methyl formate (MF), methyl acetate (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 (4MeDOL), dimethoxymethane (DMM), 1,2-dimethoxypropane (DMP), Triethylene glycol dimethyl ether (DG), dimethyl sulfone (MSM), dimethyl ether (DME), ethylene 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-tetrafluoroboron salt, 1-ethyl-3-methylimidazole-bistrifluoromethylsulfonimide salt, 1-propyl-3-methylimidazole-hexafluorophosphate, 1-propyl-3-methyl Imidazole-tetrafluoroborate, 1-propyl-3-methylimidazole-bistrifluoromethylsulfonimide salt, 1-butyl-1-methylimidazole-hexafluorophosphate, 1-butyl -1-methylimidazole-tetrafluoroborate, 1-butyl-1-methylimidazole-bistrifluoromethylsulfonimide salt, N-butyl-N-methylpyrrolidine-bistrifluoro Methylsulfonimide salt, 1-butyl-1-methylpyrrolidine-bistrifluoromethylsulfonyl imide salt, N-methyl-N-propylpyrrolidine-bistrifluoromethylsulfonyl One or more of imide salts, N-methyl, propylpiperidine-bistrifluoromethylsulfonimide salts, N-methyl, butylpiperidine-bistrifluoromethylsulfonimide salts .
7. A preparation method of calcium salt electrolyte, is characterized in that, comprises the following steps:

   Adopt the preparation method of calcium salt electrolyte as described in any one in claim 1-6 to prepare calcium salt electrolyte;

   The organic solvent is then removed, or the solubility of the calcium salt in the organic solvent is reduced to precipitate the calcium salt solute.
8. A calcium salt electrolyte, characterized in that it is prepared by the preparation method of the calcium salt electrolyte according to claim 7.
9. A calcium salt electrolyte, characterized in that it is prepared by the preparation method of the calcium salt electrolyte according to any one of claims 1-6;

   Or obtain by redissolving the calcium salt electrolyte described in claim 8 in other organic solvents.
10. A kind of calcium ion battery, comprises battery negative pole, electrolytic solution, diaphragm and battery positive pole, is characterized in that, described electrolytic solution is the calcium salt electrolytic solution described in claim 9.
11. An energy storage device, characterized by comprising the calcium ion battery as claimed in claim 10.
12. An electrical device, characterized by comprising the calcium ion battery as claimed in claim 10.

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