Preparation method of potassium supplement additive for potassium battery and potassium battery

Abstract

The invention discloses a preparation method of a potassium battery potassium supplement additive in the technical field of batteries, which comprises the following steps: fully dissolving precursor molecules in a solvent, adding a reducing agent, fully reacting, adding a stabilizer, stirring for a set time, and finally performing spray drying in an inert gas atmosphere to obtain the potassium battery potassium supplement additive. The problems that an existing potassium supplementing material is single in function, and an electrode interface cannot be effectively stabilized while potassium is efficiently supplemented are solved.

Description

Technical Field

[0001] This invention relates to the field of battery technology, and in particular to a potassium battery. Background Technology

[0002] Potassium-ion batteries, with their abundant potassium resources (2.09%) and relatively low standard electrode potential (-2.93V vs. SHE), have shown potential to replace lithium-ion batteries in large-scale energy storage. However, the solid electrolyte interface (SEI) formed during potassium insertion / extraction in graphite anodes irreversibly consumes potassium ions, resulting in low coulombic efficiency in the first cycle (typically <80%), severely limiting the battery's energy density and cycle life. An ideal potassium replenishment agent must meet the following conditions: the decomposition voltage must match the operating window of the potassium-ion battery (0.5-4.5V vs. K). + / K); avoid using materials containing heavy metals (such as KCrO2) or gas-producing components (such as K2C2O4); the raw material cost must be lower than the market price of potassium salts (such as less than 1 / 5 of KPF6); and it must be air-stable. Current technological bottlenecks include: while K2CO3 is inexpensive, its decomposition product CO2 can cause battery swelling; although KFePO4 is non-toxic, its potassium replenishment capacity is only 82mAh / g; organic potassium salts (such as KOTf) cause a surge in electrolyte viscosity; and most potassium-rich materials have poor air stability. Therefore, exploring new battery potassium replenishment materials and finding more ideal potassium replenishment reagents is of great value. Summary of the Invention

[0003] To address the shortcomings of existing technologies, this invention provides a method for preparing a potassium supplement additive for potassium batteries and a potassium battery, which solves the problems of existing potassium supplement materials having limited functions and being unable to effectively stabilize the electrode interface while efficiently supplementing potassium.

[0004] The objective of this invention is achieved as follows: a method for preparing a potassium-supplementing additive for potassium batteries, comprising the following steps: after fully dissolving a precursor molecule in a solvent, adding a reducing agent, and after sufficient reaction, adding a stabilizer and stirring for a set time, and finally spray drying under an inert gas atmosphere to obtain the potassium-supplementing additive for potassium batteries; wherein the precursor molecule is one or a combination of γ-hydroxybutyric acid, lactic acid, o-cresol, trifluoromethanesulfonic acid, 2-(2-hydroxypropoxy)-1-propanol, 3-hydroxybutyric acid, 4-tert-butylcyclohexanol, 4-isopropylcyclohexanol, and 4-hydroxy-3-hexanone.

[0005] Furthermore, the solvent is one or a combination of heptane, acetonitrile, tetrahydrofuran, ethylene glycol dimethyl ether, and dimethyl carbonate.

[0006] Furthermore, the reducing agent is one or a combination of potassium hydride, potassium metal, potassium borohydride, and potassium ascorbate.

[0007] Furthermore, the concentration of the reducing agent is 0.006–0.03 mol / L.

[0008] Furthermore, the stabilizer is one or a combination of carbon black, carbon nanotubes, polymethyl methacrylate, potassium carbonate, and potassium fluoride.

[0009] Furthermore, the process of fully dissolving the precursor molecules in the solvent specifically involves: under an inert gas atmosphere, taking 100–200 mL of solvent, adding 0.003–0.01 mol of the precursor, and stirring for 30–60 min to dissolve it at a temperature of 30–50°C and a high-speed stirring rate of 200–800 r / min to form a homogeneous and stable solution.

[0010] Furthermore, the complete reaction specifically involves adding potassium hydride, potassium metal, potassium borohydride, and potassium ascorbate, then stirring at a speed of 200–800 r / min, with a reaction temperature of 30–50°C, until the reaction is complete.

[0011] Furthermore, the spray drying under the inert gas atmosphere is preferably carried out at a temperature of 70–110°C.

[0012] Furthermore, the electrochemical window of the potassium battery potassium supplement is between 0.5 and 4.2 V, which can provide additional capacity during the first charge of the potassium battery.

[0013] A potassium battery is assembled by combining the aforementioned potassium battery potassium supplementation additive with the electrode or adding it to the electrolyte. The positive electrode includes one of Prussian blue, potassium vanadium phosphate, potassium vanadium manganese phosphate, nickel cobalt manganese ternary material, and potassium vanadium fluorophosphate. The negative electrode includes one of graphite, hard carbon, soft carbon, and graphene-based negative electrode. The electrolyte is a carbonate electrolyte.

[0014] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0015] This invention utilizes specific organic molecules as precursors and reacts them with potassium-containing reagents through a controlled chemical reaction process to prepare an organic composite material with highly efficient potassium replenishment capabilities. This potassium-replenishing additive exhibits excellent compatibility, allowing for uniform mixing with the positive electrode material, negative electrode material, and electrolyte during battery fabrication. During the first charge of the battery, the additive can controllably release pre-stored potassium ions, effectively compensating for the loss of active potassium caused by the formation of the solid electrolyte interphase (SEI) film and side reactions. This innovative potassium replenishment strategy significantly improves the initial coulombic efficiency and cycle stability of potassium-ion batteries, providing a new technical approach for developing high-performance potassium-ion batteries. Compared with existing electrolyte potassium replenishment materials (such as K2C2O4, KCrO2, and K2CO3), the organic potassium replenishment material of this invention exhibits significant comprehensive advantages: First, in terms of material synthesis, the organic precursor has mild reaction conditions and strong process controllability; second, in terms of depotassium removal characteristics, it has a more suitable depotassium removal voltage window, enabling more precise control of potassium ion release; furthermore, the prepared potassium replenishment additive is air-stable and can be used in the positive electrode, electrolyte, and negative electrode; most importantly, the organic residue formed after depotassium removal can build a stable protective layer on the electrode surface, effectively inhibiting electrolyte decomposition and electrode structure degradation, thereby significantly improving the long-cycle stability of the battery. This dual-functional characteristic of "potassium replenishment-stabilization" is the innovative breakthrough of this material. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0017] Figure 1 The diagram shows the specific capacity and discharge capacity of the potassium-supplementing material prepared in Example 1 of the invention during the first charging cycle.

[0018] Figure 2 The image shows a scanning electron microscope (SEM) image of the potassium supplementation additive prepared in Example 1 of the invention.

[0019] Figure 3 The cycle number and charge / discharge specific capacity curves of the battery assembled with the potassium-supplemented material prepared in Example 1 of the invention. Detailed Implementation

[0020] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] Example 1

[0022] A method for preparing a potassium supplement additive for potassium batteries includes the following steps:

[0023] Step 1: Under an inert gas atmosphere, take 100 mL of tetrahydrofuran, add 0.003 mol of γ-hydroxybutyric acid and stir for 30 min to dissolve. The stirring speed is 200 r / min and the dissolution temperature is 30℃. Dissolve completely to form a stable solution system.

[0024] Step 2: Under an inert gas atmosphere, add 0.006 mol of potassium hydride to the solution from Step 1, and stir at high speed to allow the solution system from Step 1 to react rapidly with potassium hydride. The reaction temperature is 30℃, the stirring speed is 200 r / min, and the reaction is allowed to proceed for 24 hours.

[0025] Step 3: After the reaction is complete, remove the reaction solution and add carbon black, stirring for 24 hours.

[0026] Step 4: After the stabilizer is fully mixed, remove the reaction solution and spray dry it under an inert gas atmosphere at 70°C to obtain the potassium supplementation additive for potassium batteries.

[0027] Under the specific environmental conditions of a normal chemical laboratory, the experimental data obtained through the above-described embodiments are as follows:

[0028]

[0029] like Figure 1 As shown, the specific technical content disclosed is as follows: through Figure 1 It can be seen that the prepared potassium-supplemented material exhibits a specific capacity of 269 mAh / g during the first charge cycle, while the discharge capacity is almost zero, demonstrating its excellent pre-potassiumization capability.

[0030] like Figure 2 As shown, the specific technical content revealed is: scanning electron microscope image of the prepared potassium supplement additive.

[0031] like Figure 3 As shown, the specific technical content disclosed is: the cycle number and charge / discharge specific capacity curve of the battery assembled with the prepared potassium-supplemented material.

[0032] Example 2

[0033] A method for preparing a potassium supplement additive for potassium batteries includes the following steps:

[0034] Step 1: Under an inert gas atmosphere, take 200 mL of acetonitrile, add 0.01 mol of lactic acid and stir for 60 min to dissolve. The dissolution temperature of lactic acid is 50℃, and the high-speed stirring speed is 800 r / min to ensure that the lactic acid is fully dissolved and a homogeneous solution system is formed.

[0035] Step 2: Under an inert gas atmosphere, add 0.03 mol of potassium metal and stir at high speed to allow the solution system from Step 1 to react rapidly with the potassium metal. The reaction temperature is 50℃, the stirring speed is 800 r / min, and the reaction is allowed to proceed for 24 h.

[0036] Step 3: After the reaction is complete, remove the reaction solution and add potassium fluoride, stirring for 24 hours.

[0037] Step 4: After the stabilizer is fully mixed, remove the reaction solution and spray dry it under an inert gas atmosphere at 110°C to obtain the potassium supplement additive for potassium batteries.

[0038] Under the specific environmental conditions of a normal chemical laboratory, the experimental data obtained through the above-described embodiments are as follows:

[0039]

[0040] Example 3

[0041] A method for preparing a potassium supplement additive for potassium batteries includes the following steps:

[0042] Step 1: Under an inert gas atmosphere, take 150 mL of dimethyl carbonate, add 0.005 mol of 3-hydroxybutyric acid and stir for 50 min to dissolve. The dissolution temperature of 3-hydroxybutyric acid is 40℃, and the high-speed stirring speed is 700 r / min to ensure that 3-hydroxybutyric acid is fully dissolved and a homogeneous solution system is formed.

[0043] Step 2: Under an inert gas atmosphere, add 0.02 mol potassium borohydride and stir at high speed to allow the solution system from Step 1 to react rapidly with potassium borohydride. The reaction temperature is 40℃, the stirring speed is 700 r / min, and the reaction is allowed to proceed for 24 h.

[0044] Step 3: After the reaction is complete, remove the reaction solution and add polymethyl methacrylate, stirring for 24 hours.

[0045] Step 4: After the stabilizer is fully mixed, remove the reaction solution and spray dry it under an inert gas atmosphere at 80°C to obtain the potassium supplementation additive for potassium batteries.

[0046] Under the specific environmental conditions of a normal chemical laboratory, the experimental data obtained through the above-described embodiments are as follows:

[0047]

[0048] Example 4

[0049] A method for preparing a potassium supplement additive for potassium batteries includes the following steps:

[0050] Step 1: Under an inert gas atmosphere, take 150 mL of heptane, add 0.005 mol of pyrogallol and stir for 50 min to dissolve. The dissolution temperature of pyrogallol is 45℃. The high-speed stirring speed is 700 r / min to ensure that the pyrogallol is fully dissolved and a homogeneous solution system is formed.

[0051] Step 2: Under an inert gas atmosphere, add 0.02 mol potassium borohydride and stir at high speed to allow the solution system from Step 1 to react rapidly with potassium borohydride. The reaction temperature is 45℃, the stirring speed is 700 r / min, and the reaction is allowed to proceed for 24 h.

[0052] Step 3: After the reaction is complete, remove the reaction solution and add polymethyl methacrylate, stirring for 24 hours.

[0053] Step 4: After the stabilizer is fully mixed, remove the reaction solution and spray dry it under an inert gas atmosphere at 80°C to obtain the potassium supplementation additive for potassium batteries.

[0054] Under the specific environmental conditions of a normal chemical laboratory, the experimental data obtained through the above-described embodiments are as follows:

[0055]

[0056] Example 5

[0057] A method for preparing a potassium supplement additive for potassium batteries includes the following steps:

[0058] Step 1: Under an inert gas atmosphere, take 200 mL of ethylene glycol dimethyl ether, add 0.005 mol of pyrogallol and stir for 50 min to dissolve. The dissolution temperature of pyrogallol is 45℃. The high-speed stirring speed is 700 r / min to ensure that the pyrogallol is fully dissolved and a homogeneous solution system is formed.

[0059] Step 2: Under an inert gas atmosphere, add 0.02 mol potassium borohydride and stir at high speed to allow the solution system from Step 1 to react rapidly with potassium borohydride. The reaction temperature is 45℃, the stirring speed is 700 r / min, and the reaction is allowed to proceed for 24 h.

[0060] Step 3: After the reaction is complete, remove the reaction solution and add polymethyl methacrylate, stirring for 24 hours.

[0061] Step 4: After the stabilizer is fully mixed, remove the reaction solution and spray dry it under an inert gas atmosphere at 80°C to obtain the potassium supplementation additive for potassium batteries.

[0062] Under the specific environmental conditions of a normal chemical laboratory, the experimental data obtained through the above-described embodiments are as follows:

[0063]

[0064] Example 6

[0065] A method for preparing a potassium supplement additive for potassium batteries includes the following steps:

[0066] Step 1: Under an inert gas atmosphere, take 200 mL of acetonitrile and add 0.005 mol of 2-fluoro-4-hydroxybenzonitrile. Stir for 50 min to dissolve. The dissolution temperature of 2-fluoro-4-hydroxybenzonitrile is 45℃. The high-speed stirring speed is 700 r / min to ensure that 2-fluoro-4-hydroxybenzonitrile is fully dissolved to form a homogeneous solution system.

[0067] Step 2: Under an inert gas atmosphere, add 0.02 mol of potassium ascorbate and stir at high speed to allow the solution system from Step 1 to react rapidly with potassium ascorbate. The reaction temperature is 45℃, the stirring speed is 700 r / min, and the reaction is allowed to proceed for 24 h.

[0068] Step 3: After the reaction is complete, remove the reaction solution and add carbon nanotubes, stirring for 24 hours.

[0069] Step 4: After the stabilizer is fully mixed, remove the reaction solution and spray dry it under an inert gas atmosphere at 70°C to obtain the potassium supplementation additive for potassium batteries.

[0070] Under the specific environmental conditions of a normal chemical laboratory, the experimental data obtained through the above-described embodiments are as follows:

[0071]

[0072] Compared with existing technologies, this invention uses precursors such as organic acids to synthesize potassium-replenishing materials for potassium batteries with dual functions of "potassium replenishment and stabilization" through reaction with potassium-replenishing reagents. Compared with current potassium-replenishing materials, it has a suitable depotassium removal potential, potassium replenishment capacity, and strong air stability. The performance and stability of potassium batteries are significantly improved after adding potassium-replenishing additives.

[0073] Example 7

[0074] A potassium battery is assembled by combining a potassium battery potassium supplementation additive with an electrode or adding it to an electrolyte. The positive electrode includes one of Prussian blue, potassium vanadium phosphate, potassium vanadium manganese phosphate, nickel cobalt manganese ternary material, and potassium vanadium fluorophosphate. The negative electrode includes one of graphite, hard carbon, soft carbon, and graphene-based negative electrode. The electrolyte is a carbonate electrolyte.

[0075] The potassium supplementation performance of the added potassium additive is as follows: Under normal chemical laboratory conditions, the potassium supplementation additive prepared in Example 6 was added to the potassium battery electrolyte, and the battery performance data are as follows:

[0076]

[0077] The above description of the embodiments is only for the purpose of helping to understand the method and core ideas of the present invention. It should be noted that those skilled in the art can make several improvements and modifications to the present invention without departing from the principles of the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

Claims

1. A method for preparing a potassium supplement additive for potassium batteries, characterized in that, Includes the following steps: After the precursor molecules are fully dissolved in the solvent, a reducing agent is added. After the reaction is complete, a stabilizer is added and the mixture is stirred for a set time. Finally, the mixture is spray-dried under an inert gas atmosphere to obtain a potassium supplement additive for potassium batteries. The precursor molecule is one or a combination of γ-hydroxybutyric acid, lactic acid, o-cresol, trifluoromethanesulfonic acid, 2-(2-hydroxypropoxy)-1-propanol, 3-hydroxybutyric acid, 4-tert-butylcyclohexanol, 4-isopropylcyclohexanol, and 4-hydroxy-3-hexanone.

2. The method for preparing a potassium supplement additive for potassium batteries according to claim 1, characterized in that, The solvent is one or a combination of heptane, acetonitrile, tetrahydrofuran, ethylene glycol dimethyl ether, and dimethyl carbonate.

3. A method for preparing a potassium supplement additive for potassium batteries according to claim 1 or 2, characterized in that, The reducing agent is one or a combination of potassium hydride, potassium metal, potassium borohydride, and potassium ascorbate.

4. The method for preparing a potassium supplement additive for potassium batteries according to claim 3, characterized in that, The concentration of the reducing agent is 0.006–0.03 mol / L.

5. A method for preparing a potassium supplement additive for potassium batteries according to claim 1 or 2, characterized in that, The stabilizer is one or a combination of carbon black, carbon nanotubes, polymethyl methacrylate, potassium carbonate, and potassium fluoride.

6. A method for preparing a potassium supplement additive for potassium batteries according to claim 1 or 2, characterized in that, The process of fully dissolving the precursor molecules in the solvent specifically involves: under an inert gas atmosphere, taking 100–200 mL of solvent, adding 0.003–0.01 mol of the precursor, and stirring for 30–60 min to dissolve it. The dissolution temperature is 30–50 °C, and the high-speed stirring speed is 200–800 r / min to form a homogeneous and stable solution.

7. A method for preparing a potassium supplement additive for potassium batteries according to claim 1 or 2, characterized in that, The complete reaction is specifically achieved by adding potassium hydride, potassium metal, potassium borohydride, and potassium ascorbate, stirring at a speed of 200–800 r / min, and maintaining a reaction temperature of 30–50°C until the reaction is complete.

8. A method for preparing a potassium supplement additive for potassium batteries according to claim 1 or 2, characterized in that, The spray drying is performed under an inert gas atmosphere, and the preferred drying temperature is 70–110°C.

9. A method for preparing a potassium supplement additive for potassium batteries according to claim 1 or 2, characterized in that, The potassium battery potassium supplement additive has an electrochemical window between 0.5 and 4.2 V, which can provide additional capacity during the first charge of the potassium battery.

10. A potassium battery, characterized in that, The device is assembled by combining the potassium supplement additive for potassium batteries according to any one of claims 1-9 with the electrode or adding it to the electrolyte. The positive electrode includes one of Prussian blue, potassium vanadium phosphate, potassium vanadium manganese phosphate, nickel cobalt manganese ternary material, and potassium vanadium fluorophosphate. The negative electrode includes one of graphite, hard carbon, soft carbon, and graphene-based negative electrode. The electrolyte is a carbonate electrolyte.

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