阅读说明：本技术 一种碳布基钾金属复合电极及其制备方法与应用 (Carbon cloth-based potassium metal composite electrode and preparation method and application thereof ) 是由 王选朋 乔凡 麦立强 王军军 于 2021-08-18 设计创作，主要内容包括：本发明提供了一种碳布基钾金属复合电极及其制备方法与应用,制备方法包括步骤：将无水氯化亚锡溶解于N,N-二甲基甲酰胺溶液中,搅拌均匀后依次加入对苯二甲酸、聚乙烯吡咯烷酮,得到混合液；将碳布置入混合液内,在预设条件下静置反应,后取出碳布,洗涤、烘干后得到前驱体；将前驱体置于马弗炉进行煅烧,得到碳布基亲钾骨架材料；将碳布基亲钾骨架材料浸入金属钾熔融液,即得到碳布基钾金属复合电极。本发明提供的碳布基钾金属复合电极,在作为钾离子电池负极材料时,展示了优异的倍率与循环稳定性；与3,4,9,10-四甲酰二亚胺组装成的全电池表现出优异的电化学性能,在新型储能装置以钾离子二次电池中有很好的应用和发展。(The invention provides a carbon cloth-based potassium metal composite electrode and a preparation method and application thereof, wherein the preparation method comprises the following steps: dissolving anhydrous stannous chloride in an N, N-dimethylformamide solution, uniformly stirring, and sequentially adding terephthalic acid and polyvinylpyrrolidone to obtain a mixed solution; placing the carbon cloth into the mixed solution, standing for reaction under a preset condition, taking out the carbon cloth, washing and drying to obtain a precursor; placing the precursor in a muffle furnace for calcining to obtain a carbon cloth-based potassium-philic framework material; and (3) immersing the carbon cloth-based potassium-philic framework material into the metal potassium melt to obtain the carbon cloth-based potassium metal composite electrode. The carbon cloth-based potassium metal composite electrode provided by the invention shows excellent multiplying power and cycling stability when being used as a potassium ion battery cathode material; the full battery assembled with the 3,4,9, 10-tetracarboxydiimide has excellent electrochemical performance and is well applied and developed in novel energy storage devices and potassium ion secondary batteries.)

1. A preparation method of a carbon cloth-based potassium metal composite electrode is characterized by comprising the following steps:

s1, dissolving anhydrous stannous chloride in N, N-dimethylformamide solution, stirring uniformly, and then sequentially adding terephthalic acid and polyvinylpyrrolidone to obtain a mixed solution;

s2, placing carbon cloth into the mixed solution, standing for reaction under preset conditions, taking out the carbon cloth, washing and drying to obtain a precursor;

s3, placing the precursor in a muffle furnace for calcining to obtain the carbon-cloth-based potassium-philic framework material;

and S4, immersing the carbon cloth-based potassium-philic framework material into the metal potassium melt to obtain the carbon cloth-based potassium metal composite electrode.

2. The method as claimed in claim 1, wherein the N, N-dimethylformamide solution, the anhydrous stannous chloride, the terephthalic acid and the polyvinylpyrrolidone are used in a ratio of (35ml-90ml), (0.25g-0.35g), (0.11g-0.13g) and (0.09g-0.11g) in step S1.

3. The method as claimed in claim 1, wherein the preset conditions of step S2 include a reaction temperature ranging from 160 ℃ to 180 ℃ and a reaction time ranging from 11h to 13 h.

4. The method according to claim 3, wherein the washing in step S2 is a plurality of washes with absolute ethanol.

5. The method according to any one of claims 1 to 4, wherein the calcination conditions in step S3 include a calcination temperature in the range of 400 ℃ to 450 ℃ and a calcination time in the range of 2.5h to 3.5 h.

6. The method according to claim 5, wherein the potassium metal melt of step S4 is prepared by a method comprising: in a glove box with the water oxygen value lower than 0.01ppm, the bulk metal potassium is heated to a molten state and has certain fluidity.

7. A carbon cloth-based potassium metal composite electrode characterized by being produced by the method for producing a carbon cloth-based potassium metal composite electrode according to any one of claims 1 to 6.

8. The carbon cloth-based potassium metal composite electrode according to claim 7, comprising a tin dioxide modified potassium-philic carbon cloth skeleton and potassium metal infiltrated in the tin dioxide modified potassium-philic carbon cloth skeleton.

9. A potassium ion battery comprising the carbon cloth-based potassium metal composite electrode according to claim 7 or 8.

10. The potassium ion battery of claim 9, wherein the battery negative electrode material is the carbon cloth-based potassium metal composite electrode, the battery positive electrode material is 3,4,9, 10-tetracarboxydiimide, the electrolyte is KFSI-EC/DMC, and the separator is glass fiber.

Technical Field

The invention relates to the technical field of electrochemistry, in particular to a carbon cloth-based potassium metal composite electrode and a preparation method and application thereof.

Background

With the rapid development of electric vehicles and portable electronic products, people have an increasing demand for secondary batteries, lithium ion batteries have a slow energy density increase and a slow cost reduction, and have challenges in terms of rapid charging, temperature range adaptation, larger-scale deployment and application (electric vehicles, energy storage) and resource abundance. Secondary batteries composed of elements rich in the earth are now required to supplement the shortages of lithium ion batteries, and potassium ion batteries have attracted much attention as a potential substitute for lithium ion batteries. However, the side reaction between the active chemical property of the metal potassium and the organic electrolyte is serious, so that the metal potassium is irreversibly consumed and a large amount of inactive potassium is accumulated, and the metal potassium cathode can generate volume deformation in the circulation process to deteriorate the circulation stability; and potassium dendrite generated in the circulation process can pierce through a diaphragm, so that the internal short circuit and thermal runaway of the battery are caused, and even fire, explosion and other dangers are caused, and the practical application of the potassium metal cathode is severely limited.

In order to solve the above problems, researchers have proposed various coping strategies including electrolyte composition and concentration regulation, construction of artificial SEI and composite potassium metal negative electrodes, etc., but none of them can achieve the goals of suppressing dendrite growth and alleviating volume expansion.

Therefore, it is very important to search for a potassium metal negative electrode material with simple operation and stable performance.

Disclosure of Invention

In view of the above, the invention aims to overcome the defects in the prior art, and provides a carbon cloth-based potassium metal composite electrode, and a preparation method and application thereof, so as to solve the problems of poor rate capability and poor cycle stability of the existing potassium ion battery cathode material.

In order to achieve the purpose, the technical scheme of the invention is realized as follows:

a preparation method of a carbon cloth-based potassium metal composite electrode comprises the following steps:

s1, dissolving anhydrous stannous chloride in N, N-dimethylformamide solution, stirring uniformly, and then sequentially adding terephthalic acid and polyvinylpyrrolidone to obtain a mixed solution;

s2, placing carbon cloth into the mixed solution, standing for reaction under preset conditions, taking out the carbon cloth, washing and drying to obtain a precursor;

s3, placing the precursor in a muffle furnace for calcining to obtain the carbon-cloth-based potassium-philic framework material;

and S4, immersing the carbon cloth-based potassium-philic framework material into the metal potassium melt to obtain the carbon cloth-based potassium metal composite electrode.

Optionally, the N, N-dimethylformamide solution, the anhydrous stannous chloride, the terephthalic acid and the polyvinylpyrrolidone are used in a ratio (35ml-90ml) to (0.25g-0.35g) to (0.11g-0.13g) to (0.09g-0.11g) in step S1.

Optionally, the preset conditions of step S2 include a reaction temperature in the range of 160 ℃ to 180 ℃ and a reaction time in the range of 11h to 13 h.

Alternatively, the washing in step S2 is multiple rinsing with absolute ethanol.

Alternatively, the calcining conditions of step S3 include calcining temperature in the range of 400 ℃ to 450 ℃ and calcining time in the range of 2.5h to 3.5 h.

Alternatively, the method for preparing the potassium metal melt in step S4 includes: in a glove box with the water oxygen value lower than 0.01ppm, the bulk metal potassium is heated to a molten state and has certain fluidity.

The invention also aims to provide a carbon cloth-based potassium metal composite electrode which is prepared by adopting the preparation method of the carbon cloth-based potassium metal composite electrode.

Optionally, the carbon cloth-based potassium metal composite electrode includes a tin dioxide modified potassium-philic carbon cloth skeleton and potassium metal infiltrated in the tin dioxide modified potassium-philic carbon cloth skeleton.

The invention also provides a potassium ion battery, which comprises the carbon cloth-based potassium metal composite electrode.

Optionally, the battery cathode material of the potassium ion battery is the carbon cloth-based potassium metal composite electrode, the battery anode material is 3,4,9, 10-tetracarboxydiimide, the electrolyte is KFSI-EC/DMC, and the diaphragm is glass fiber.

Compared with the prior art, the carbon cloth-based potassium metal composite electrode and the preparation method and application thereof provided by the invention have the following advantages:

(1) the carbon cloth-based potassium metal composite electrode formed by infiltrating molten metal potassium with the carbon cloth skeleton modified by tin dioxide has a certain pore structure and a larger specific surface area, effectively increases the contact area between electrolyte and metal potassium, and shows excellent multiplying power and cycling stability when being used as a potassium ion battery cathode material; the full battery assembled with the 3,4,9, 10-tetracarboxydiimide has excellent electrochemical performance and is well applied and developed in novel energy storage devices and potassium ion secondary batteries.

(2) The preparation method is simple, the raw materials are simple and easy to obtain, and the prepared carbon cloth-based potassium metal composite electrode is smooth in shape, stable in structure and suitable for industrial production.

Drawings

In order to more clearly illustrate the technical solutions of the present invention or the prior art, the drawings needed for the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and those skilled in the art can also obtain other drawings according to the drawings without creative efforts.

FIG. 1 is a flow chart of the preparation of a carbon cloth-based potassium metal composite electrode according to an embodiment of the present invention;

FIG. 2 is K-CC @ SnO shown in example 1 of the present invention₂XRD spectrum of (1);

FIG. 3 is K-CC @ SnO defined in example 1 of the invention₂Cross-sectional SEM images of;

FIG. 4 is K-CC @ SnO as set forth in example 1 of the present invention₂A multiplying power performance comparison graph of the assembled symmetrical battery and a symmetrical battery assembled by a pure potassium electrode;

FIG. 5 is K-CC @ SnO as set forth in example 1 of the present invention₂Rate performance plot of the full cell assembled with PTCDI;

FIG. 6 is K-CC @ SnO as set forth in example 1 of the invention₂Long cycle performance plots for full cells assembled with PTCDI;

FIG. 7 is K-CC @ SnO defined in example 1 of the invention₂Cycling performance plots for full cells assembled with PTCDI.

Detailed Description

In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in detail below.

It should be noted that in the description of the embodiments herein, the description of the term "some embodiments" means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. Throughout this specification, the schematic representations of the terms used above do not necessarily refer to the same implementation or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

The term "in.. range" as used herein includes both ends, such as "in the range of 1 to 100" including both ends of 1 and 100.

The potassium metal and the lithium metal belong to the first main group and have similar physical and chemical properties, and the electrode potential (-2.93V) of potassium ions is similar to that of lithium ions (-3.04V), so that the potassium ion battery is the same as the lithium ion battery and has the advantage of high voltage; and potassium ions with larger radii than sodium ions can intercalate into graphite and provide a specific capacity of about 250 mAh/g. The metal potassium cathode is an ideal choice for the cathode material of the potassium ion battery due to high theoretical specific capacity (687mAh/g) and lower standard potential (-2.93Vvs standard hydrogen electrode). However, in practical applications, since the electrochemical activity of the potassium metal is higher, repeated electrochemical deposition and removal processes can cause severe volume expansion and uncontrolled dendrite growth, resulting in an unstable solid electrolyte membrane (SEI) on the surface of the negative electrode, thereby causing reduced coulombic efficiency, poor electrochemical stability, and even internal short circuit to cause fire safety hazard, which seriously hinders the large-scale application of the potassium metal negative electrode.

In the existing research, the three-dimensional framework has a higher specific surface area and can obviously reduce the local current density of the negative electrode, so that the initial nucleation time point of potassium dendrite is delayed, the porous structure of the three-dimensional framework can limit the growth of metal potassium in the three-dimensional framework, and the volume expansion of the metal potassium in the charging and discharging process is relieved. However, since the heterogeneous nucleation energy barrier of the metal potassium on the framework material is high, potassium ions are preferentially nucleated at local 'hot spots' on the surface of the framework in the initial stage, and in the subsequent deposition process, the potassium ions preferentially nucleate and grow on the deposited metal potassium, so that uneven metal potassium deposition behavior is caused, and the three-dimensional framework is difficult to play a preset role.

In order to solve the above problems, an embodiment of the present invention provides a method for preparing a carbon cloth-based potassium metal composite electrode, which is shown in fig. 1, and includes the following steps:

a preparation method of a carbon cloth-based potassium metal composite electrode comprises the following steps:

s1, dissolving anhydrous stannous chloride in N, N-dimethylformamide solution, stirring uniformly, and then sequentially adding terephthalic acid and polyvinylpyrrolidone to obtain a mixed solution;

s2, placing the carbon cloth into the mixed solution, standing for reaction under a preset condition, taking out the carbon cloth, washing and drying to obtain a precursor;

s3, placing the precursor in a muffle furnace for calcination to obtain the carbon cloth-based potassium-philic framework material CC @ SnO₂；

S4, immersing the carbon cloth-based potassium-philic framework material into the metal potassium melt to obtain the carbon cloth-based potassium metal composite electrode K-CC @ SnO₂。

It is understood that a potassium-philic framework refers to a framework material that facilitates uniform nucleation of potassium metal upon introduction of potassium-philic sites or surface modification. The introduction of the potassium-philic framework is an effective strategy for realizing uniform deposition of the potassium metal, and has important practical significance for the development of potassium metal cathode batteries.

The embodiment of the invention is based onA three-dimensional framework optimization mechanism, provides a tin dioxide SnO₂The modified carbon cloth base potassium-philic framework is prepared by soaking metal potassium in the potassium-philic framework by a melting method to prepare K-CC @ SnO₂And an electrode. K-CC @ SnO₂The composite electrode has a certain pore structure and a larger specific surface area, so that the contact area between the electrolyte and the metal potassium is effectively increased, an effective electron and potassium ion electrochemical reaction network is formed, the electrochemical reaction process is accelerated, and the problem of potassium dendrite formed by local electron enrichment in the circulation process is solved; the three-dimensional structure of the carbon cloth greatly accelerates the diffusion efficiency of potassium ions and realizes good rate performance; the three-dimensional space structure of the carbon cloth can accommodate the problem of volume expansion of the potassium ion battery in the circulating process and effectively release the stress of potassium ions in the de-intercalation process, and the circulating stability of the electrode is improved.

Specifically, in step S1, dissolving anhydrous stannous chloride in N, N-dimethylformamide solution, fully stirring until all the stannous chloride is dissolved to obtain clear solution, adding terephthalic acid, and fully stirring until the solution is clear; and finally, adding polyvinylpyrrolidone (K30) into the clear solution, and fully stirring until the polyvinylpyrrolidone is completely dissolved to obtain a mixed solution.

Furthermore, the dosage ratio of the N, N-dimethylformamide solution, the anhydrous stannous chloride, the terephthalic acid and the polyvinylpyrrolidone is within the range of (35ml-90ml), (0.25g-0.35g), (0.11g-0.13g) and (0.09g-0.11 g). Preferably, the ratio of the amount of the N, N-dimethylformamide solution, the anhydrous stannous chloride, the terephthalic acid and the polyvinylpyrrolidone is 50ml:0.3g:0.12g:0.1 g.

Specifically, in step S2, a commercial carbon cloth with a size of 5cm × 5cm is immersed in the mixed solution, then the solution is transferred to a reaction kettle and placed in an oven, standing reaction is performed under preset conditions, after the reaction is completed, the carbon cloth taken out is washed three times with absolute ethyl alcohol, and then dried to obtain a precursor.

Wherein the preset conditions of the standing reaction comprise that the reaction temperature is in the range of 170 ℃ to 180 ℃ and the reaction time is in the range of 11h to 13 h. Preferably, the reaction temperature is 170 ℃ and the reaction time is 12 h.

Specifically, in step S3, the calcination conditions of the precursor in the muffle furnace include a calcination temperature in the range of 400 ℃ to 450 ℃, a calcination time in the range of 2.5h to 3.5h, and a temperature rise rate in the range of 1 ℃/min to 5 ℃/min. Preferably, the calcination temperature is 425 ℃, the calcination time is 3h, and the temperature rise speed is 3 ℃/min.

Modifying a layer of SnO on carbon cloth by utilizing simple solvothermal₂Particles, after high temperature calcination, can be coated with SnO₂The high-potassium-affinity composite material not only has a porous structure, but also can reduce the binding energy of the composite material and potassium atoms.

Specifically, in step S4, bulk potassium metal is heated to a molten state and has certain fluidity in a glove box with a water oxygen value lower than 0.01ppm, and CC @ SnO is coated₂Placed on molten potassium until the metallic potassium completely covers the CC @ SnO₂Taking out and cooling to room temperature to obtain K-CC @ SnO₂。

The preparation method is simple, the raw materials are simple and easy to obtain, and the prepared carbon cloth-based potassium metal composite electrode is smooth in shape, stable in structure and suitable for industrial production.

The invention also provides a carbon cloth-based potassium metal composite electrode which is prepared by adopting the preparation method of the carbon cloth-based potassium metal composite electrode.

The carbon cloth-based potassium metal composite electrode comprises a stannic oxide modified potassium-philic carbon cloth framework and potassium metal infiltrated in the stannic oxide modified potassium-philic carbon cloth framework. Namely, the metal potassium is uniformly distributed in the carbon cloth space framework and has rich space structure.

Another embodiment of the present invention provides a potassium ion battery, including the above carbon cloth-based potassium metal composite electrode. The battery cathode material is a carbon cloth-based potassium metal composite electrode, the battery anode material is 3,4,9, 10-tetracarboxydiimide, the electrolyte is KFSI-EC/DMC, and the diaphragm is glass fiber.

Experiments prove that the K-CC @ SnO formed in the potassium-philic framework₂The composite electrode has better rate performance and long cycle life when being used as a negative electrode material of a potassium ion battery, and has practical applicationThe potassium ion battery cathode material with high value.

On the basis of the above embodiments, the present invention will be further illustrated by the following specific examples of the method for producing a carbon-cloth-based potassium metal composite electrode. It should be understood that these examples are for illustrative purposes only and are not intended to limit the scope of the present invention. The following examples are examples of experimental procedures not specified under specific conditions, generally according to the conditions recommended by the manufacturer. Unless otherwise indicated, percentages and parts are by mass.

Example 1

The embodiment provides a preparation method of a carbon cloth-based potassium metal composite electrode, which comprises the following steps:

1) dissolving 0.12g of anhydrous stannous chloride in 70ml of N, N-dimethylformamide solution, fully stirring until the anhydrous stannous chloride is completely dissolved, adding 0.12g of terephthalic acid, fully stirring until the terephthalic acid is clear, then adding 0.1g of polyvinylpyrrolidone (K30), and respectively stirring until the polyvinylpyrrolidone is completely dissolved;

2) adding 5cm by 5cm commercial carbon cloth into the mixed solution obtained in the step 1), transferring the solution to a 100ml reaction kettle, putting the reaction kettle into a 180 ℃ oven, preserving the heat for 12 hours, taking out the carbon cloth, washing the carbon cloth with absolute ethyl alcohol for three times, and then drying the carbon cloth to obtain a precursor;

3) calcining the precursor in a muffle furnace at 450 ℃ for 3 hours to obtain SnO₂Modified carbon cloth-based potassium-philic framework material CC @ SnO₂；

4) Heating and melting the potassium block in a glove box, and then adding CC @ SnO₂Immersing into molten metal potassium to obtain the K-CC @ SnO of the carbon cloth-based potassium metal composite electrode₂。

For K-CC @ SnO prepared in example 1₂The structure characterization is performed by using X-ray diffraction (XRD) and Scanning Electron Microscope (SEM), and the result graphs shown in figures 2 and 3 are obtained. As can be seen from FIG. 2, K-CC @ SnO₂Successful impregnation of potassium metal in the composite electrode (JCPDS card number 05-0500). As can be seen from the cross-sectional scanning electron micrograph of FIG. 3, K-CC @ SnO₂In the composite electrode, the surface of a single carbon cloth fiber is uniformly coated with metal potassium with the diameter of about 1 mu m. This demonstrates the chemical composition formed by SnO₂The modified potassium-philic carbon cloth skeleton can successfully prepare K-CC @ SnO₂The composite electrode overcomes the defect that the potassium metal is soft and difficult to prepare, and has certain feasibility.

The K-CC @ SnO prepared in example 1₂Symmetrical battery K-CC @ SnO assembled by composite electrodes₂||[email protected]₂The performance test comparison of the symmetric battery and the full battery K I K assembled by the pure potassium electrode plates is carried out, and the result is shown in FIG. 4. As seen in FIG. 4, K-CC @ SnO was observed at different current densities₂||[email protected]₂The overpotential of the symmetrical batteries is smaller than K. When the current density is from 0.5mA/cm²Increased to 1mA/cm²、2mA/cm²、3mA/cm²、4mA/cm²And 5mA/cm²Then return to 0.5mA/cm²The overpotential of the filter is 95mV, 126mV, 170mV, 205mV, 230mV and 253mV respectively. Indicating K-CC @ SnO₂The composite electrode has excellent stability.

The K-CC @ SnO prepared in example 1₂The composite electrode is used as a negative electrode material of a potassium ion battery, 3,4,9, 10-tetracarboxydiimide (PTCDI) is used as a positive electrode material, KFSI-EC/DMC is used as an electrolyte, glass fiber is used as a diaphragm, CR2016 type stainless steel is used as a capacitor shell, and a button potassium ion capacitor (PTCDI K-CC @ SnO) is assembled₂Full cell) and subjected to electrochemical performance test, resulting in graphs of results shown in fig. 5 to 7.

The preparation method of the cathode material adopts a general preparation method, and is not described herein again. The preparation method of the positive plate comprises the following steps:

PTCDI is used as an active material, acetylene black is used as a conductive agent, polyvinylidene fluoride PVDF is used as a binder, the mass ratio of the active material, the acetylene black and the PVDF is 7:2:1, the active material, the acetylene black and the PVDF are fully mixed according to the proportion and then are uniformly coated on a carbon-coated aluminum foil; and (3) drying the coated positive plate in a vacuum oven at 120 ℃ for 10 hours to obtain the positive plate.

The electrolyte is KFSI-EC/DMC, which comprises the following components: 1mol/L potassium bis (fluorosulfonyl) imide KFSI is dissolved in Ethylene Carbonate (EC) and diethyl carbonate (DEC), and mixed according to the volume ratio of 1:1 to be used as electrolyte.

FIG. 5 is PTCDI K-CC @ SnO₂Rate capability of full cellAs can be seen from FIG. 5, when the current density was increased from 50mA/g to 2000mA/g, the reversible capacities thereof were 127mAh/g, 125mAh/g, 123mAh/g, 121mAh/g, 119mAh/g and 116mAh/g, respectively. At a large current density of 5000mA, the full cell still had a high discharge capacity of 112 mAh/g. When the current density returned to 50mA/g, its capacity was restored to 116mAh/g (approximately 91.3% of the initial value). This indicates PTCDI K-CC @ SnO₂The full cell has excellent rate performance.

FIG. 6 is PTCDI K-CC @ SnO₂Long cycle performance diagram of the whole cell, PTCDI K-CC @ SnO₂The long cycle stability test at 2000mA/g shows that the whole battery has an ultra-long cycle life of 10000 cycles and the capacity retention rate is 70.9%.

FIG. 7 is PTCDI K-CC @ SnO₂The cycle performance of the full cell is shown in FIG. 7, in which the discharge capacity was 130.6mAh/g, the average operating potential was 2.1V, and the energy density was 274Wh/kg at a current density of 100 mA/g. Under the current density of 100mA/g, the specific capacity of 105.1mAh/g is still kept after 500 times of circulation, and the capacity retention rate is 80.5 percent.

In summary, the K-CC @ SnO provided by the embodiment of the invention₂The full cell assembled with PTCDI has excellent rate performance and long cycle performance, and simultaneously shows that the K-CC @ SnO prepared by the potassium-philic framework provided by the invention₂The potassium battery has certain practical application significance as a potassium battery strategy.

Example 2

The embodiment provides a preparation method of a carbon cloth-based potassium metal composite electrode, which is different from the embodiment 1 in that:

in the step 1), 0.12g of anhydrous stannous chloride is dissolved in 35ml of N, N-dimethylformamide solution, and the mixture is fully stirred until the stannous chloride is completely dissolved;

the remaining steps and parameters were the same as in example 1.

The K-CC @ SnO prepared in example 2₂The composite electrode is used as a negative electrode material of the potassium ion battery, and is assembled into a full battery according to the method for carrying out electrochemical performance test. The capacity is still 125mAh/g when the current density is 50mA/g, and the circulation is carried out when the current density is 100mA/gAfter 1000 circles, the capacity can reach 88 mAh/g.

Example 3

The embodiment provides a preparation method of a carbon cloth-based potassium metal composite electrode, which is different from the embodiment 1 in that:

in the step 1), 0.12g of anhydrous stannous chloride is dissolved in 80ml of N, N-dimethylformamide solution, and the mixture is fully stirred until the stannous chloride is completely dissolved;

the remaining steps and parameters were the same as in example 1.

The K-CC @ SnO prepared in example 3₂The composite electrode is used as a negative electrode material of the potassium ion battery, and is assembled into a full battery according to the method for carrying out electrochemical performance test. When the current density is 50mA/g, the capacity is still 103mAh/g, and when the current density is 100mA/g, the capacity can reach 80mAh/g after 1000 cycles.

Example 4

The embodiment provides a preparation method of a carbon cloth-based potassium metal composite electrode, which is different from the embodiment 1 in that:

in the step 1), 0.12g of anhydrous stannous chloride is dissolved in 90ml of N, N-dimethylformamide solution, and the mixture is fully stirred until the stannous chloride is completely dissolved;

the remaining steps and parameters were the same as in example 1.

The K-CC @ SnO prepared in example 4₂The composite electrode is used as a negative electrode material of the potassium ion battery, and is assembled into a full battery according to the method for carrying out electrochemical performance test. When the current density is 50mA/g, the capacity is still 98mAh/g, and when the current density is 100mA/g, the capacity can reach 78mAh/g after 1000 times of circulation.

Although the present disclosure has been described above, the scope of the present disclosure is not limited thereto. Various changes and modifications may be effected therein by one of ordinary skill in the pertinent art without departing from the spirit and scope of the present disclosure, and these changes and modifications are intended to be within the scope of the present disclosure.