Modified electrolyte of sodium-ion battery, sodium-ion battery and electric equipment

Abstract

The invention provides a modified electrolyte of a sodium-ion battery and the sodium-ion battery, relates to electric equipment, and relates to the field of sodium-ion batteries. The modified electrolyte of the sodium ion battery provided by the invention comprises an electrolyte solute and a basic electrolyte, and the electrolyte solute comprises acetylacetone salt; the basic electrolyte comprises sodium perchlorate, propylene carbonate and fluoroethylene carbonate; the acetylacetone salt comprises one or more of ferrous acetylacetonate, ferric acetylacetonate, manganese acetylacetonate and cobalt acetylacetonate. The structure collapse caused by the dissolution of transition metal ions in the circulation process of the Prussian blue material is inhibited through electrode liquid modification, so that the circulation stability is effectively improved.

Description

Technical Field

[0001] The present application relates to the field of sodium ion batteries, and in particular to a modified electrolyte for sodium ion batteries, sodium ion batteries, and electrical equipment. Background Art

[0002] Sodium ion batteries (SIBs) are considered to be one of the most suitable alternatives for future large-scale energy storage systems due to their low cost, high natural abundance, and wide distribution. There are many types of positive electrode materials for SIBs, among which Prussian blue analogues are favorable for Na+ due to their unique open large framework structure and large interstitial space. + The rapid insertion and extraction of ions, low cost, environmental friendliness, simple preparation process, stable structure and other advantages have attracted great attention in recent years.

[0003] However, Prussian blue analogs still face many challenges in practical applications: (1) Removal of crystalline water and defects: Prussian blue analogs are prone to produce crystalline water and structural defects during the synthesis process, which can affect the electrochemical properties of the material, such as specific capacity and cycle stability. (2) Jahn-Teller effect: This causes structural collapse and complex phase transitions during the charge and discharge process, which seriously affects the cycle stability.

[0004] However, Prussian blue materials have a serious attenuation problem. General research mainly focuses on improving the crystallinity of the material and reducing the water and defect content of the material itself. Cyclic stability has indeed been improved, but there is still obvious attenuation. Therefore, how to modify the electrode liquid by modifying the electrolyte to inhibit the structural collapse caused by the dissolution of transition metal ions in Prussian blue materials during the cycle, thereby effectively improving the cycle stability, has become a current research difficulty. Summary of the invention

[0005] The purpose of this application is to provide a modified electrolyte for a sodium ion battery, a sodium ion battery, and electrical equipment to solve the above-mentioned problems.

[0006] To achieve the above objectives, this application adopts the following technical solutions:

[0007] The present application provides a modified electrolyte for a sodium ion battery, comprising an electrolyte solute and a basic electrolyte, wherein the electrolyte solute comprises acetylacetonate; the basic electrolyte comprises sodium perchlorate, propylene carbonate, and fluoroethylene carbonate;

[0008] The acetylacetonate salt includes one or more of ferrous acetylacetonate, ferric acetylacetonate, manganese acetylacetonate, and cobalt acetylacetonate.

[0009] Optionally, based on the total volume of propylene carbonate and fluoroethylene carbonate being 100 Vol%, the propylene carbonate is 90-99%, and the fluoroethylene carbonate is 1-10%; the concentration of sodium perchlorate in the basic electrolyte is 0.8-1 mol / L;

[0010] Optionally, the corresponding relationship between the acetylacetonate and the basic electrolyte is that every 1 to 5 mg of the acetylacetonate corresponds to 1 ml of the basic electrolyte.

[0011] The present application also provides a sodium ion battery, and its raw material is the modified electrolyte of the sodium ion battery.

[0012] Optionally, the raw material of the sodium ion battery further includes a positive electrode material, the positive electrode material includes a Prussian blue material, and the preparation method of the Prussian blue material includes the following steps:

[0013] dissolving the first core raw material and the first complexing agent in a first solvent to obtain a first solution;

[0014] dissolving the metal salt and the second complexing agent in a second solvent to obtain a second solution;

[0015] The second solution is added dropwise to the first solution under the protection of an inert gas, and after all the solution is added, the solution is continuously stirred for reaction, and after the reaction is completed, the solution is allowed to stand for aging, and the Prussian blue material is obtained after post-treatment;

[0016] Among them, the first core raw material includes sodium ferrocyanide; the metal salt includes ferrous sulfate; the first complexing agent and the second complexing agent each independently include sodium citrate.

[0017] Optionally, during the preparation of the Prussian blue material, the first solvent and the second solvent independently include deoxygenated deionized water.

[0018] Optionally, during the preparation of the Prussian blue material, the inactive gas includes nitrogen.

[0019] Optionally, during the preparation of the Prussian blue material, the concentration of the first core raw material is 0.01-0.2 mol / L.

[0020] Optionally, during the preparation of the Prussian blue material, the concentration of the first complexing agent is 0.01-0.25 mol / L.

[0021] Optionally, during the preparation of the Prussian blue material, the concentration of the second complexing agent is 0.01-0.25 mol / L.

[0022] Optionally, during the preparation of the Prussian blue material, the molar ratio of the first complexing agent to the second complexing agent is (1-3):1.

[0023] Optionally, during the preparation of the Prussian blue material, the reaction temperature is 5 to 80° C. and the reaction time is 0.5 to 48 h.

[0024] Optionally, during the preparation of the Prussian blue material, the static aging time is 2 to 48 hours.

[0025] Optionally, in the preparation process of the Prussian blue material, the post-treatment process includes centrifugal separation, washing and drying.

[0026] Optionally, during the preparation of the Prussian blue material, the drying is vacuum drying, the temperature of the vacuum drying is 80 to 150° C., and the time is 10 to 48 hours.

[0027] The present application also provides an electrical device, comprising the sodium ion battery.

[0028] Compared with the prior art, the beneficial effects of this application include:

[0029] The present application provides a modified electrolyte for a sodium ion battery, which makes innovations in the electrolyte. By modifying the electrode liquid, the structural collapse caused by the dissolution of transition metal ions in Prussian blue materials during the cycle process is suppressed, thereby effectively improving the cycle stability.

[0030] The present application also provides a sodium ion battery including a modified electrolyte of the Prussian blue material. It also includes a Prussian blue analog. The Prussian blue material prepared by the traditional method has low crystallinity, defects and high water molecule content, resulting in low specific capacity, poor rate performance, and short cycle life. This is mainly due to the fact that the low-crystallinity structure is prone to collapse during the cycle and the serious Jan-Taylor effect of the Mn-based material. The Prussian blue analog provided by the present invention is used as a positive electrode material, and the chelating effect of the chelating agent on the metal ions is utilized to slow down the release rate of the metal ions. The Prussian blue crystals grow slowly and have high crystallinity, showing excellent electrochemical properties, high specific capacity and stable cycle.

[0031] The present application also provides an electrical device with excellent electrical performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope of the present application.

[0033] Figure 1This is a scanning electron microscope (SEM) image of the Prussian blue material prepared in Example 1 of the present application. DETAILED DESCRIPTION

[0034] As used herein:

[0035] "Prepared from" is synonymous with "comprising." As used herein, the terms "comprising," "including," "having," "containing," or any other variation thereof, are intended to cover a non-exclusive inclusion. For example, a composition, process, method, article, or apparatus that comprises the listed elements is not necessarily limited to only those elements but may include other elements not expressly listed or inherent to such composition, process, method, article, or apparatus.

[0036] The conjunction "consisting of excludes any unspecified element, step, or component. If used in a claim, this phrase renders the claim closed-ended so that it does not include materials other than those described, except for conventional impurities associated therewith. When the phrase "consisting of" appears in a clause of the body of a claim rather than immediately following the subject matter, it limits only the elements described in that clause; other elements are not excluded from the claim as a whole.

[0037] When an amount, concentration, or other value or parameter is expressed as a range, a preferred range, or a range defined by a series of upper preferred values ​​and lower preferred values, this should be understood as specifically disclosing all ranges formed by any pairing of any range upper limit or preferred value with any range lower limit or preferred value, regardless of whether the range is disclosed separately. For example, when a range of "1 to 5" is disclosed, the described range should be interpreted as including ranges "1 to 4", "1 to 3", "1 to 2", "1 to 2 and 4 to 5", "1 to 3 and 5", etc. When a numerical range is described in this article, unless otherwise stated, the range is intended to include its end values ​​and all integers and fractions within the range.

[0038] In these examples, parts and percentages are by mass unless otherwise indicated.

[0039] "Parts by mass" refers to the basic unit of measurement for expressing the mass ratio of multiple components. 1 part can represent any unit mass, such as 1g or 2.689g. If we say that the mass of component A is a parts and the mass of component B is b parts, it means the ratio of the mass of component A to the mass of component B is a:b. Alternatively, it means that the mass of component A is aK and the mass of component B is bK (K is an arbitrary number, indicating a multiple factor). It should not be misunderstood that, unlike the mass parts, the sum of the mass of all components is not limited to 100 parts.

[0040] "And / or" is used to indicate that one or both of the stated situations may occur, for example, A and / or B includes (A and B) and (A or B).

[0041] In a first aspect, the present application provides a modified electrolyte for a sodium ion battery, comprising an electrolyte solute and a base electrolyte, wherein the electrolyte solute comprises acetylacetonate; the base electrolyte comprises sodium perchlorate, propylene carbonate, and fluoroethylene carbonate;

[0042] The acetylacetonate salt includes one or more of ferrous acetylacetonate, ferric acetylacetonate, manganese acetylacetonate, and cobalt acetylacetonate.

[0043] In an optional embodiment, based on the total volume of propylene carbonate and fluoroethylene carbonate being 100 Vol%, the propylene carbonate is 90-99%, and the fluoroethylene carbonate is 1-10%; the concentration of sodium perchlorate in the electrolyte is 0.8-1 mol / L.

[0044] In an optional embodiment, the corresponding relationship between the acetylacetonate and the basic electrolyte is that every 1 to 5 mg of the acetylacetonate corresponds to 1 ml of the basic electrolyte.

[0045] In a second aspect, the present application also provides a sodium ion battery, the raw material of which is the modified electrolyte of the sodium ion battery.

[0046] In an optional embodiment, the raw material of the sodium ion battery further includes a positive electrode material, the positive electrode material includes a Prussian blue material, and the preparation method of the Prussian blue material includes the following steps:

[0047] dissolving the first core raw material and the first complexing agent in a first solvent to obtain a first solution;

[0048] dissolving the metal salt and the second complexing agent in a second solvent to obtain a second solution;

[0049] The second solution is added dropwise to the first solution under the protection of an inert gas, and after all the solution is added, the solution is continuously stirred for reaction, and after the reaction is completed, the solution is allowed to stand for aging, and the Prussian blue material is obtained after post-treatment;

[0050] The first core raw material includes sodium ferrocyanide; the metal salt includes ferrous sulfate; the first complexing agent and the second complexing agent each independently include sodium citrate.

[0051] In an optional embodiment, during the preparation of the Prussian blue material, the first solvent and the second solvent each independently include deoxygenated deionized water.

[0052] In an optional embodiment, during the preparation of the Prussian blue material, the inactive gas includes nitrogen.

[0053] In an optional embodiment, during the preparation of the Prussian blue material, the concentration of the first core raw material is 0.01-0.2 mol / L.

[0054] Optionally, the concentration of the first core raw material can be 0.01mol / L, 0.03mol / L, 0.05mol / L, 0.07mol / L, 0.09mol / L, 0.11mol / L, 0.13mol / L, 0.15mol / L, 0.17mol / L, 0.19mol / L, 0.2mol / L, or any value between 0.01 and 0.2mol / L.

[0055] In an optional embodiment, during the preparation of the Prussian blue material, the concentration of the first complexing agent is 0.01-0.25 mol / L.

[0056] The concentration of the first complexing agent can be 0.01mol / L, 0.03mol / L, 0.05mol / L, 0.07mol / L, 0.09mol / L, 0.11mol / L, 0.13mol / L, 0.15mol / L, 0.17mol / L, 0.19mol / L, 0.2mol / L, 0.21mol / L, 0.22mol / L, 0.23mol / L, 0.24mol / L, 0.25mol / L, or any value between 0.01 and 0.25mol / L.

[0057] In an optional embodiment, during the preparation of the Prussian blue material, the concentration of the second complexing agent is 0.01-0.25 mol / L.

[0058] The concentration of the second complexing agent can be 0.01mol / L, 0.03mol / L, 0.05mol / L, 0.07mol / L, 0.09mol / L, 0.11mol / L, 0.13mol / L, 0.15mol / L, 0.17mol / L, 0.19mol / L, 0.2mol / L, 0.21mol / L, 0.22mol / L, 0.23mol / L, 0.24mol / L, 0.25mol / L, or any value between 0.01 and 0.25mol / L.

[0059] In an optional embodiment, during the preparation of the Prussian blue material, the molar ratio of the first complexing agent to the second complexing agent is (1-3):1.

[0060] Optionally, the molar ratio of the first complexing agent to the second complexing agent can be 1:1, 1.2:1, 1.4:1, 1.6:1, 1.8:1, 2:1, 2.2:1, 2.4:1, 2.6:1, 2.8:1, 3:1, or any ratio between (1-3):1.

[0061] In an optional embodiment, during the preparation of the Prussian blue material, the reaction temperature is 5 to 80° C. and the reaction time is 0.5 to 48 hours.

[0062] Optionally, the reaction temperature can be 5°C, 10°C, 15°C, 20°C, 25°C, 30°C, 35°C, 40°C, 45°C, 50°C, 55°C, 60°C, 65°C, 70°C, 75°C, 80°C, or any value between 5 and 80°C.

[0063] In an optional embodiment, during the preparation of the Prussian blue material, the static aging time is 2 to 48 hours.

[0064] Optionally, the refined aging time can be 2h, 4h, 8h, 12h, 16h, 20h, 24h, 28h, 32h, 36h, 40h, 42h, 48h, or any value between 2 and 48h.

[0065] In an optional embodiment, during the preparation of the Prussian blue material, the post-treatment process includes centrifugal separation, washing, and drying.

[0066] In an optional embodiment, during the preparation of the Prussian blue material, the drying is vacuum drying, and the temperature of the vacuum drying is 80 to 150° C., and the time is 10 to 48 hours.

[0067] Optionally, the vacuum drying temperature may be 80° C., 85° C., 90° C., 95° C., 100° C., 105° C., 110° C., 115° C., 120° C., 125° C., 130° C., 135° C., 140° C., 145° C., 150° C., or any value between 80 and 150° C. The vacuum drying time may be 10 h, 12 h, 14 h, 16 h, 20 h, 24 h, 28 h, 32 h, 36 h, 40 h, 42 h, 48 h, or any value between 10 and 48 h.

[0068] In a third aspect, the present application also provides an electrical device, including the sodium ion battery.

[0069] The embodiments of the present application will be described in detail below in conjunction with specific examples, but it will be appreciated by those skilled in the art that the following examples are only used to illustrate the present application and should not be considered as limiting the scope of the present application. If specific conditions are not specified in the examples, they are carried out according to normal conditions or the conditions recommended by the manufacturer. If the manufacturer is not specified for the reagents or instruments used, they are all conventional products that can be purchased commercially.

[0070] Example 1

[0071] This embodiment provides a modified electrolyte for a sodium ion battery, and the preparation method thereof is as follows:

[0072] (1) Taking the volume of the basic electrolyte solution as 100 Vol%, 1 mol of sodium perchlorate is dissolved in a mixed solvent of 90 Vol% of propylene carbonate and 10 Vol% of fluoroethylene carbonate to obtain an electrolyte solution.

[0073] (2) In a glove box under an argon atmosphere, 5 mg of ferrous acetylacetonate was dissolved in 1 ml of a basic electrolyte to obtain a modified electrolyte for a sodium ion battery.

[0074] This embodiment also provides a sodium ion battery, and the preparation method thereof is as follows:

[0075] (3) 10 mmol of sodium citrate and 5 mmol of sodium ferrocyanide were dissolved in 100 mL of deoxygenated deionized water to obtain a first solution.

[0076] (4) 5 mmol of FeSO4·7H2O and 10 mmol of sodium citrate were dissolved in 100 mL of deoxygenated deionized water to obtain a second solution.

[0077] (5) At 25°C, slowly drop the second solution into the first solution, stir and react for 24 hours, and then age for 24 hours. Wash with deoxygenated deionized water and ethanol three times, and collect the precipitate. Finally, vacuum dry at 120°C for 24 hours to obtain a Prussian blue material. The SEM image is as follows: Figure 1 shown.

[0078] (6) 240 mg of Prussian blue material powder is placed in a weighing bottle, 30 mg of Ketjen black, 30 mg of PVDF, and an appropriate amount of N-methyl-2-pyrrolidone are added, and the mixture is thoroughly stirred. The mixture is then coated on an aluminum foil and dried. Sodium metal is used as a counter electrode, the modified electrolyte in step (2) is used, and the diaphragm is a glass fiber diaphragm to prepare a 2032 button cell.

[0079] Example 2

[0080] This embodiment provides a modified electrolyte for a sodium ion battery, and the preparation method is as follows:

[0081] (1) Taking the volume of the basic electrolyte solution as 100 Vol%, 0.8 mol of sodium perchlorate was dissolved in a mixed solvent of 92 Vol% of propylene carbonate and 8 Vol% of fluoroethylene carbonate to obtain an electrolyte solution.

[0082] (2) In a glove box under an argon atmosphere, 2 mg of ferrous acetylacetonate was dissolved in 1 ml of a basic electrolyte to obtain a modified electrolyte for a sodium ion battery.

[0083] This embodiment also provides a sodium ion battery, and the preparation method thereof is as follows:

[0084] (3) 15 mmol of sodium citrate and 3 mmol of sodium ferrocyanide were dissolved in 100 mL of deoxygenated deionized water to obtain a first solution.

[0085] (4) 3 mmol of FeSO4·7H2O and 15 mmol of sodium citrate were dissolved in 100 mL of deoxygenated deionized water to obtain a second solution.

[0086] (5) At 25°C, the second solution was slowly added dropwise to the first solution, and the mixture was stirred for 24 hours, and then aged for 24 hours. The mixture was washed three times with deoxygenated deionized water and ethanol, and the precipitate was collected. Finally, the mixture was vacuum dried at 120°C for 24 hours to obtain a Prussian blue material as a positive electrode material.

[0087] (6) 240 mg of Prussian blue material powder is placed in a weighing bottle, 30 mg of Ketjen black, 30 mg of PVDF, and an appropriate amount of N-methyl-2-pyrrolidone are added, and the mixture is thoroughly stirred. The mixture is then coated on an aluminum foil and dried. Sodium metal is used as a counter electrode, the modified electrolyte in step (2) is used, and the diaphragm is a glass fiber diaphragm to prepare a 2032 button cell.

[0088] Example 3

[0089] This embodiment provides a modified electrolyte for a sodium ion battery, and the preparation method is as follows:

[0090] (1) Taking the volume of the basic electrolyte solution as 100 Vol%, 0.9 mol of sodium perchlorate was dissolved in a mixed solvent of 94 Vol% of propylene carbonate and 6 Vol% of fluoroethylene carbonate to obtain an electrolyte solution.

[0091] (2) In a glove box under an argon atmosphere, 2 mg of ferrous acetylacetonate was dissolved in 1 ml of a basic electrolyte to obtain a modified electrolyte for a sodium ion battery.

[0092] This embodiment also provides a sodium ion battery, and the preparation method thereof is as follows:

[0093] (3) 25 mmol of sodium citrate and 5 mmol of sodium ferrocyanide were dissolved in 100 mL of deoxygenated deionized water to obtain a first solution.

[0094] (4) 5 mmol of FeSO4·7H2O and 25 mmol of sodium citrate were dissolved in 100 mL of deoxygenated deionized water to obtain a second solution.

[0095] (5) At 25°C, the second solution was slowly added dropwise to the first solution, and the mixture was stirred for 24 hours, and then aged for 24 hours. The mixture was washed three times with deoxygenated deionized water and ethanol, and the precipitate was collected. Finally, the mixture was vacuum dried at 120°C for 24 hours to obtain a Prussian blue material as a positive electrode material.

[0096] (6) 240 mg of Prussian blue material powder is placed in a weighing bottle, 30 mg of Ketjen black, 30 mg of PVDF, and an appropriate amount of N-methyl-2-pyrrolidone are added, and the mixture is thoroughly stirred. The mixture is then coated on an aluminum foil and dried. Sodium metal is used as a counter electrode, the modified electrolyte in step (2) is used, and the diaphragm is a glass fiber diaphragm to prepare a 2032 button cell.

[0097] Example 4

[0098] This embodiment provides a modified electrolyte for a sodium ion battery, and the preparation method is as follows:

[0099] (1) Taking the volume of the basic electrolyte solution as 100 Vol%, 1 mol of sodium perchlorate is dissolved in a mixed solvent of 95 Vol% of propylene carbonate and 5 Vol% of fluoroethylene carbonate to obtain an electrolyte solution.

[0100] (2) In a glove box under an argon atmosphere, 2 mg of ferrous acetylacetonate was dissolved in 1 ml of a basic electrolyte to obtain a modified electrolyte for a sodium ion battery.

[0101] This embodiment also provides a sodium ion battery, and the preparation method thereof is as follows:

[0102] (3) 12 mmol of sodium citrate and 5 mmol of sodium ferrocyanide were dissolved in 100 mL of deoxygenated deionized water to obtain a first solution.

[0103] (4) 5 mmol of FeSO4·7H2O and 12 mmol of sodium citrate were dissolved in 100 mL of deoxygenated deionized water to obtain a second solution.

[0104] (5) At 25°C, the second solution was slowly added dropwise to the first solution, and the mixture was stirred for 24 hours, and then aged for 24 hours. The mixture was washed three times with deoxygenated deionized water and ethanol, and the precipitate was collected. Finally, the mixture was vacuum dried at 120°C for 24 hours to obtain a Prussian blue material as a positive electrode material.

[0105] (6) 240 mg of Prussian blue material powder is placed in a weighing bottle, 30 mg of Ketjen black, 30 mg of PVDF, and an appropriate amount of N-methyl-2-pyrrolidone are added, and the mixture is thoroughly stirred. The mixture is then coated on an aluminum foil and dried. Sodium metal is used as a counter electrode, the modified electrolyte in step (2) is used, and the diaphragm is a glass fiber diaphragm to prepare a 2032 button cell.

[0106] Example 5

[0107] This embodiment provides a modified electrolyte for a sodium ion battery, and the preparation method is as follows:

[0108] (1) Taking the volume of the basic electrolyte solution as 100 Vol%, 1 mol of sodium perchlorate is dissolved in a mixed solvent of 96 Vol% of propylene carbonate and 4 Vol% of fluoroethylene carbonate to obtain an electrolyte solution.

[0109] (2) In a glove box under an argon atmosphere, 5 mg of manganese acetylacetonate was dissolved in 1 ml of a basic electrolyte to obtain a modified electrolyte for a sodium ion battery.

[0110] This embodiment also provides a sodium ion battery, and the preparation method thereof is as follows:

[0111] (3) 10 mmol of sodium citrate and 5 mmol of sodium ferrocyanide were dissolved in 100 mL of deoxygenated deionized water to obtain a first solution.

[0112] (4) 5 mmol of FeSO4·7H2O and 10 mmol of sodium citrate were dissolved in 100 mL of deoxygenated deionized water to obtain a second solution.

[0113] (5) At 25°C, the second solution was slowly added dropwise to the first solution, and the mixture was stirred for 24 hours, and then aged for 24 hours. The mixture was washed three times with deoxygenated deionized water and ethanol, and the precipitate was collected. Finally, the mixture was vacuum dried at 120°C for 24 hours to obtain a Prussian blue material as a positive electrode material.

[0114] (6) 240 mg of Prussian blue material powder is placed in a weighing bottle, 30 mg of Ketjen black, 30 mg of PVDF, and an appropriate amount of N-methyl-2-pyrrolidone are added, and the mixture is thoroughly stirred. The mixture is then coated on an aluminum foil and dried. Sodium metal is used as a counter electrode, the modified electrolyte in step (2) is used, and the diaphragm is a glass fiber diaphragm to prepare a 2032 button cell.

[0115] Example 6

[0116] This embodiment provides a modified electrolyte for a sodium ion battery, and the preparation method is as follows:

[0117] (1) Taking the volume of the basic electrolyte solution as 100 Vol%, 1 mol of sodium perchlorate is dissolved in a mixed solvent of 97 Vol% of propylene carbonate and 3 Vol% of fluoroethylene carbonate to obtain an electrolyte solution.

[0118] (2) In a glove box under an argon atmosphere, 2.5 mg of manganese acetylacetonate and 2.5 mg of ferrous acetylacetonate were dissolved in 1 ml of a basic electrolyte to obtain a modified electrolyte for a sodium ion battery.

[0119] This embodiment also provides a sodium ion battery, and the preparation method thereof is as follows:

[0120] (3) 10 mmol of sodium citrate and 5 mmol of sodium ferrocyanide were dissolved in 100 mL of deoxygenated deionized water to obtain a first solution.

[0121] (4) 5 mmol of FeSO4·7H2O and 10 mmol of sodium citrate were dissolved in 100 mL of deoxygenated deionized water to obtain a second solution.

[0122] (5) At 25°C, the second solution was slowly added dropwise to the first solution, and the mixture was stirred for 24 hours, and then aged for 24 hours. The mixture was washed three times with deoxygenated deionized water and ethanol, and the precipitate was collected. Finally, the mixture was vacuum dried at 120°C for 24 hours to obtain a Prussian blue material as a positive electrode material.

[0123] (6) 240 mg of Prussian blue material powder is placed in a weighing bottle, 30 mg of Ketjen black, 30 mg of PVDF, and an appropriate amount of N-methyl-2-pyrrolidone are added, and the mixture is thoroughly stirred. The mixture is then coated on an aluminum foil and dried. Sodium metal is used as a counter electrode, the modified electrolyte in step (2) is used, and the diaphragm is a glass fiber diaphragm to prepare a 2032 button cell.

[0124] Example 7

[0125] This embodiment provides a modified electrolyte for a sodium ion battery, and the preparation method is as follows:

[0126] (1) Taking the volume of the basic electrolyte solution as 100 Vol%, 1 mol of sodium perchlorate is dissolved in a mixed solvent of 98 Vol% of propylene carbonate and 2 Vol% of fluoroethylene carbonate to obtain an electrolyte solution.

[0127] (2) In a glove box under an argon atmosphere, 5 mg of cobalt acetylacetonate was dissolved in 1 ml of a basic electrolyte to obtain a modified electrolyte for a sodium ion battery.

[0128] This embodiment also provides a sodium ion battery, and the preparation method thereof is as follows:

[0129] (3) 10 mmol of sodium citrate and 5 mmol of sodium ferrocyanide were dissolved in 100 mL of deoxygenated deionized water to obtain a first solution.

[0130] (4) 5 mmol of FeSO4·7H2O and 10 mmol of sodium citrate were dissolved in 100 mL of deoxygenated deionized water to obtain a second solution.

[0131] (5) At 25°C, the second solution was slowly added dropwise to the first solution, and the mixture was stirred for 24 hours, and then aged for 24 hours. The mixture was washed three times with deoxygenated deionized water and ethanol, and the precipitate was collected. Finally, the mixture was vacuum dried at 120°C for 24 hours to obtain a Prussian blue material as a positive electrode material.

[0132] (6) 240 mg of Prussian blue material powder is placed in a weighing bottle, 30 mg of Ketjen black, 30 mg of PVDF, and an appropriate amount of N-methyl-2-pyrrolidone are added, and the mixture is thoroughly stirred. The mixture is then coated on an aluminum foil and dried. Sodium metal is used as a counter electrode, the modified electrolyte in step (2) is used, and the diaphragm is a glass fiber diaphragm to prepare a 2032 button cell.

[0133] Example 8

[0134] This embodiment provides a modified electrolyte for a sodium ion battery, and the preparation method is as follows:

[0135] (1) Taking the volume of the basic electrolyte solution as 100 Vol%, 1 mol of sodium perchlorate is dissolved in a mixed solvent of 99 Vol% of propylene carbonate and 1 Vol% of fluoroethylene carbonate to obtain an electrolyte solution.

[0136] (2) In a glove box under an argon atmosphere, 5 mg of manganese acetylacetonate was dissolved in 1 ml of a basic electrolyte to obtain a modified electrolyte for a sodium ion battery.

[0137] This embodiment also provides a sodium ion battery, and the preparation method thereof is as follows:

[0138] (3) 10 mmol of sodium citrate and 5 mmol of sodium ferrocyanide were dissolved in 100 mL of deoxygenated deionized water to obtain a first solution.

[0139] (4) 5 mmol of FeSO4·7H2O and 10 mmol of sodium citrate were dissolved in 100 mL of deoxygenated deionized water to obtain a second solution.

[0140] (5) At 25°C, the second solution was slowly added dropwise to the first solution, and the mixture was stirred for 24 hours, and then aged for 24 hours. The mixture was washed three times with deoxygenated deionized water and ethanol, and the precipitate was collected. Finally, the mixture was vacuum dried at 120°C for 24 hours to obtain a Prussian blue material as a positive electrode material.

[0141] (6) 240 mg of Prussian blue material powder is placed in a weighing bottle, 30 mg of Ketjen black, 30 mg of PVDF, and an appropriate amount of N-methyl-2-pyrrolidone are added, and the mixture is thoroughly stirred. The mixture is then coated on an aluminum foil and dried. Sodium metal is used as a counter electrode, the modified electrolyte in step (2) is used, and the diaphragm is a glass fiber diaphragm to prepare a 2032 button cell.

[0142] Example 9

[0143] This embodiment provides a modified electrolyte for a sodium ion battery, and the preparation method is as follows:

[0144] (1) Taking the volume of the basic electrolyte solution as 100 Vol%, 1 mol of sodium perchlorate is dissolved in a mixed solvent of 95 Vol% of propylene carbonate and 5 Vol% of fluoroethylene carbonate to obtain an electrolyte solution.

[0145] (2) In a glove box under an argon atmosphere, a mixture of 3 mg of ferrous acetylacetonate, 1 mg of manganese acetylacetonate, and 1 mg of cobalt acetylacetonate was dissolved in 1 ml of a basic electrolyte to obtain a modified electrolyte for a sodium ion battery.

[0146] This embodiment also provides a sodium ion battery, and the preparation method thereof is as follows:

[0147] (3) 10 mmol of sodium citrate and 5 mmol of sodium ferrocyanide were dissolved in 100 mL of deoxygenated deionized water to obtain a first solution.

[0148] (4) 5 mmol of FeSO4·7H2O and 10 mmol of sodium citrate were dissolved in 100 mL of deoxygenated deionized water to obtain a second solution.

[0149] (5) At 25°C, the second solution was slowly added dropwise to the first solution, and the mixture was stirred for 24 hours, and then aged for 24 hours. The mixture was washed three times with deoxygenated deionized water and ethanol, and the precipitate was collected. Finally, the mixture was vacuum dried at 120°C for 24 hours to obtain a Prussian blue material as a positive electrode material.

[0150] (6) 240 mg of Prussian blue material powder is placed in a weighing bottle, 30 mg of Ketjen black, 30 mg of PVDF, and an appropriate amount of N-methyl-2-pyrrolidone are added, and the mixture is thoroughly stirred. The mixture is then coated on an aluminum foil and dried. Sodium metal is used as a counter electrode, the modified electrolyte in step (2) is used, and the diaphragm is a glass fiber diaphragm to prepare a 2032 button cell.

[0151] Comparative Example 1

[0152] This comparative example provides a modified electrolyte for a sodium ion battery, and the preparation method is as follows:

[0153] (1) Taking the volume of the basic electrolyte solution as 100 Vol%, 1 mol of sodium perchlorate is dissolved in a mixed solvent of 90 Vol% of propylene carbonate and 10 Vol% of fluoroethylene carbonate to obtain an electrolyte solution.

[0154] This comparative example also provides a sodium ion battery, and its preparation method is as follows:

[0155] (2) 10 mmol of sodium citrate and 5 mmol of sodium ferrocyanide were dissolved in 100 mL of deoxygenated deionized water to obtain a first solution.

[0156] (3) 5 mmol of FeSO4·7H2O and 10 mmol of sodium citrate were dissolved in 100 mL of deoxygenated deionized water to obtain a second solution.

[0157] (4) At 25°C, the second solution was slowly added dropwise to the first solution, and the mixture was stirred for 24 hours, and then aged for 24 hours. The mixture was washed three times with deoxygenated deionized water and ethanol, and the precipitate was collected. Finally, the mixture was vacuum dried at 120°C for 24 hours to obtain a Prussian blue material as a positive electrode material.

[0158] (5) 240 mg of Prussian blue material powder is placed in a weighing bottle, 30 mg of Ketjen black, 30 mg of PVDF, and an appropriate amount of N-methyl-2-pyrrolidone are added, and the mixture is thoroughly stirred. The mixture is then coated on an aluminum foil and dried. Sodium metal is used as a counter electrode, the modified electrolyte in step (1) is used, and the diaphragm is a glass fiber diaphragm to prepare a 2032 button cell.

[0159] Comparative Example 2

[0160] This embodiment provides a modified electrolyte for a sodium ion battery, and the preparation method thereof is as follows:

[0161] (1) Taking the volume of the basic electrolyte solution as 100 Vol%, 1 mol of sodium perchlorate is dissolved in a mixed solvent of 90 Vol% of propylene carbonate and 10 Vol% of fluoroethylene carbonate to obtain an electrolyte solution.

[0162] (2) In a glove box under an argon atmosphere, 5 mg of ferrous acetylacetonate was dissolved in 1 ml of a basic electrolyte to obtain a modified electrolyte for a sodium ion battery.

[0163] This embodiment also provides a sodium ion battery, and the preparation method thereof is as follows:

[0164] (3) 5 mmol of sodium ferrocyanide was dissolved in 100 mL of deoxygenated deionized water to obtain a first solution.

[0165] (4) Take 5 mmol of FeSO4·7H2O and dissolve it in 100 mL of deoxygenated deionized water to obtain a second solution.

[0166] (5) At 25°C, slowly drop the second solution into the first solution, stir and react for 24 hours, and then age for 24 hours. Wash with deoxygenated deionized water and ethanol three times, and collect the precipitate. Finally, vacuum dry at 120°C for 24 hours to obtain a Prussian blue material. The XRD curve of the obtained Prussian blue material is as follows: Figure 1 The SEM image is shown in Figure 1 shown.

[0167] (6) 240 mg of Prussian blue material powder is placed in a weighing bottle, 30 mg of Ketjen black, 30 mg of PVDF, and an appropriate amount of N-methyl-2-pyrrolidone are added, and the mixture is thoroughly stirred. The mixture is then coated on an aluminum foil and dried. Sodium metal is used as a counter electrode, the modified electrolyte in step (2) is used, and the diaphragm is a glass fiber diaphragm to prepare a 2032 button cell.

[0168] Comparative Example 3

[0169] This comparative example provides a modified electrolyte for a sodium ion battery, and the preparation method is as follows:

[0170] (1) Taking the volume of the basic electrolyte solution as 100 Vol%, 1 mol of sodium perchlorate is dissolved in a mixed solvent of 90 Vol% of propylene carbonate and 10 Vol% of fluoroethylene carbonate to obtain an electrolyte solution.

[0171] (2) In a glove box under an argon atmosphere, 15 mg of ferrous acetylacetonate was dissolved in 1 ml of a basic electrolyte to obtain a modified electrolyte for a sodium ion battery.

[0172] This embodiment also provides a sodium ion battery, and the preparation method thereof is as follows:

[0173] (3) 10 mmol of sodium citrate and 5 mmol of sodium ferrocyanide were dissolved in 100 mL of deoxygenated deionized water to obtain a first solution.

[0174] (4) 5 mmol of FeSO4·7H2O and 10 mmol of sodium citrate were dissolved in 100 mL of deoxygenated deionized water to obtain a second solution.

[0175] (5) At 25°C, the second solution was slowly added dropwise to the first solution, and the mixture was stirred for 24 hours, and then aged for 24 hours. The mixture was washed three times with deoxygenated deionized water and ethanol, and the precipitate was collected. Finally, the mixture was vacuum dried at 120°C for 24 hours to obtain a Prussian blue material as a positive electrode material.

[0176] (6) 240 mg of Prussian blue material powder is placed in a weighing bottle, 30 mg of Ketjen black, 30 mg of PVDF, and an appropriate amount of N-methyl-2-pyrrolidone are added, and the mixture is thoroughly stirred. The mixture is then coated on an aluminum foil and dried. Sodium metal is used as a counter electrode, the modified electrolyte in step (2) is used, and the diaphragm is a glass fiber diaphragm to prepare a 2032 button cell.

[0177] The performance of the sodium ion batteries prepared in the embodiments and comparative examples was tested on the Xinwei battery testing system, as shown in Table 1:

[0178] Table 1 Performance of sodium ion batteries prepared in the examples and comparative examples

[0179]

[0180] It can be seen that the electrolyte modified by adding acetylacetonate plays a role in stabilizing the material during the battery charging and discharging process, which helps to improve the battery cycle life. The sodium salt additive makes the material more crystalline and significantly improves the cycle capacity performance.

[0181] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit it. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.

[0182] In addition, those skilled in the art will appreciate that, although some embodiments herein include certain features included in other embodiments but not other features, the combination of features of different embodiments is meant to be within the scope of the present application and form different embodiments. For example, in the above claims, any one of the claimed embodiments may be used in any combination. The information disclosed in this background technology section is intended only to deepen the understanding of the overall background technology of the present application and should not be regarded as an admission or in any form of implication that the information constitutes prior art known to those skilled in the art.

Claims

1. A modified electrolyte for a sodium ion battery, characterized in that: It comprises an electrolyte solute and a basic electrolyte, wherein the electrolyte solute comprises acetylacetonate; the basic electrolyte comprises sodium perchlorate, propylene carbonate, and fluoroethylene carbonate; The acetylacetonate salt includes one or more of ferrous acetylacetonate, ferric acetylacetonate, manganese acetylacetonate, and cobalt acetylacetonate.

2. The modified electrolyte for sodium ion battery according to claim 1, characterized in that: At least one of the following conditions is met: a. Based on the total volume of the propylene carbonate and the fluoroethylene carbonate as 100 Vol%, the propylene carbonate is 90 to 99%, the fluoroethylene carbonate is 1 to 10%; the concentration of the sodium perchlorate in the base electrolyte is 0.8 to 1 mol / L; b. The corresponding relationship between the acetylacetonate and the basic electrolyte is that every 1 to 5 mg of the acetylacetonate corresponds to 1 ml of the basic electrolyte.

3. A sodium ion battery, characterized in that: The raw materials include the modified electrolyte of the sodium ion battery according to claim 1 or 2.

4. The sodium ion battery according to claim 3, characterized in that: The raw materials also include positive electrode materials, and the positive electrode materials include Prussian blue materials. The preparation method of the Prussian blue materials includes the following steps: dissolving a first core raw material and a first complexing agent in a first solvent to obtain a first solution; dissolving the metal salt and the second complexing agent in a second solvent to obtain a second solution; The second solution is added dropwise to the first solution under the protection of an inert gas, and after all the solution is added, the solution is continuously stirred for reaction, and after the reaction is completed, the solution is allowed to stand for aging, and the Prussian blue material is obtained after post-treatment; Among them, the first core raw material includes sodium ferrocyanide; the metal salt includes ferrous sulfate; the first complexing agent and the second complexing agent each independently include sodium citrate.

5. The sodium ion battery according to claim 4, characterized in that: During the preparation of the Prussian blue material, at least one of the following conditions is met: c. the first solvent and the second solvent each independently comprise deoxygenated deionized water; d. The inert gas includes nitrogen.

6. The sodium ion battery according to claim 4, characterized in that: During the preparation of the Prussian blue material, at least one of the following conditions is met: f. The concentration of the first core raw material is 0.01 to 0.2 mol / L; g. The concentration of the first complexing agent is 0.01 to 0.25 mol / L; h. The concentration of the second complexing agent is 0.01 to 0.25 mol / L; i. The molar ratio of the first complexing agent to the second complexing agent is (1-3):

1.

7. The sodium ion battery according to claim 4, characterized in that: During the preparation of the Prussian blue material, at least one of the following conditions is met: j. The reaction temperature is 5 to 80°C and the reaction time is 0.5 to 48h; k. The static aging time is 2 to 48 hours.

8. The sodium ion battery according to claim 4, characterized in that: In the preparation process of the Prussian blue material, the post-treatment process includes centrifugal separation, washing and drying.

9. The sodium ion battery according to claim 8, characterized in that: During the preparation of the Prussian blue material, the drying is vacuum drying, the vacuum drying temperature is 80 to 150° C., and the time is 10 to 48 hours.

10. An electrical equipment, characterized in that: A sodium ion battery comprising any one of claims 5 to 9.

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