An interfacial adhesion potassium-ion gel electrolyte and a preparation method thereof

Abstract

The application belongs to the technical field of potassium ion battery materials, and particularly relates to an interface adhesion potassium ion gel electrolyte and a preparation method thereof. Azo diisobutyronitrile is added into a potassium ion electrolyte and stirred until dissolved to obtain an electrolyte precursor; butyl acrylate and methyl methacrylate are uniformly mixed to obtain a gel electrolyte polymer precursor; the electrolyte precursor and the gel electrolyte polymer precursor are uniformly mixed and stirred to prepare a gel electrolyte precursor, and then the gel electrolyte precursor is placed in a mold for thermal polymerization to obtain the interface adhesion potassium ion gel electrolyte. The application has the advantages of short production cycle, low cost and simple operation. The prepared interface adhesion potassium ion gel electrolyte has good interface adhesion, potassium metal affinity and ion transmission performance, and can be widely applied in the field of potassium ion batteries.

Description

Technical Field

[0001] This invention belongs to the field of potassium-ion battery material technology, specifically a potassium-ion gel electrolyte with interfacial adhesion and its preparation method. Background Technology

[0002] Energy, as a crucial element of the new era, plays a vital role in the stable operation of power grids and big data systems, thus requiring suitable energy storage technologies. Currently, due to the excellent electrochemical properties of lithium metal, lithium-ion batteries, based on lithium, hold a leading position as the primary technology in both energy storage and power systems. However, with the rapid development of lithium energy storage systems in recent years, increased market demand has further led to a shortage of limited lithium raw materials, causing costs to gradually rise. Therefore, there is an urgent need to develop new electrochemical energy storage technologies to alleviate the cost pressure caused by the scaling up of lithium-ion battery systems. Potassium metal, which belongs to the same group as lithium in the periodic table, has similar electrochemical properties to lithium and has a much higher elemental reserve in the Earth's crust (2.46%) than lithium, showing promising application prospects. Most existing potassium-ion batteries are liquid battery systems based on liquid electrolytes. During cycling, dead potassium can perforate the separator, easily leading to short circuits and further causing safety and poor cycle performance problems. Organic gel electrolytes, due to their simple preparation, can effectively immobilize liquid electrolytes and alleviate the safety issues of liquid batteries to some extent. Summary of the Invention

[0003] To address the problems existing in the prior art, the main objective of this invention is to propose an interfacially bonded potassium ion gel electrolyte and its preparation method.

[0004] According to one aspect of the present invention, the present invention provides the following technical solution:

[0005] A method for preparing an interfacially adherent potassium ion gel electrolyte includes the following steps:

[0006] S1. Add azobisisobutyronitrile to the potassium ion electrolyte and stir until dissolved to obtain the electrolyte precursor;

[0007] S2. A gel electrolyte polymer precursor is obtained by uniformly mixing butyl acrylate and methyl methacrylate.

[0008] S3. The electrolyte precursor and the gel electrolyte polymer precursor are uniformly mixed and stirred to prepare the gel electrolyte precursor. Then, the gel electrolyte precursor is placed in a mold for thermal polymerization to obtain the interfacially adhered potassium ion gel electrolyte.

[0009] As a preferred embodiment of the method for preparing an interfacially bonded potassium ion gel electrolyte according to the present invention, in step S1, the potassium ion electrolyte includes a potassium salt and an organic solvent, wherein the potassium salt is KFSI (potassium bis(fluorosulfonyl)imide) and the organic solvent is ethylene carbonate and diethyl carbonate.

[0010] In a preferred embodiment of the method for preparing an interfacially bonded potassium ion gel electrolyte according to the present invention, in step S1, the amount of azobisisobutyronitrile added is 0.8-1.2 wt. of the mass of the gel electrolyte polymer precursor.

[0011] In a preferred embodiment of the method for preparing an interfacially bonded potassium ion gel electrolyte according to the present invention, in step S2, the mass ratio of butyl acrylate to methyl methacrylate is 1:(5.98-6.02).

[0012] In a preferred embodiment of the method for preparing an interfacially bonded potassium ion gel electrolyte according to the present invention, in step S3, the mass ratio of the electrolyte precursor to the electrolyte polymer precursor is (5-5.03):(2.97-3).

[0013] In a preferred embodiment of the preparation method of the interfacially bonded potassium ion gel electrolyte of the present invention, in step S3, the mixing and stirring time is ≥10 min.

[0014] In a preferred embodiment of the method for preparing an interfacially bonded potassium ion gel electrolyte according to the present invention, the thermal polymerization temperature in step S3 is ≥40℃.

[0015] In a preferred embodiment of the method for preparing an interfacially bonded potassium ion gel electrolyte according to the present invention, in step S3, the thermal polymerization time is ≥6h.

[0016] According to another aspect of the present invention, the present invention provides the following technical solution:

[0017] An interfacially bonded potassium ion gel electrolyte is prepared using the method described above.

[0018] A potassium-ion battery is assembled by placing the aforementioned interfacially bonded potassium-ion gel electrolyte between a positive electrode and a negative electrode.

[0019] In a preferred embodiment of the potassium-ion battery described in this invention, the active material of the positive electrode is 3,4,9,10-perylenetetracarboxylic dianhydride; and the negative electrode is a potassium metal sheet.

[0020] As a preferred embodiment of the potassium-ion battery described in this invention, the potassium-ion battery is a coin cell battery.

[0021] The beneficial effects of this invention are as follows:

[0022] This invention proposes an interfacially adherent potassium ion gel electrolyte and its preparation method. Azobisisobutyronitrile (AIBN) is added to a potassium ion electrolyte and stirred until dissolved to obtain an electrolyte precursor. Butyl acrylate and methyl methacrylate are uniformly mixed to obtain a gel electrolyte polymer precursor. The electrolyte precursor and the gel electrolyte polymer precursor are uniformly mixed and stirred to prepare a gel electrolyte precursor. The gel electrolyte precursor is then placed in a mold for thermal polymerization to obtain the interfacially adherent potassium ion gel electrolyte. This invention features a short production cycle, low cost, and simple operation. The prepared interfacially adherent potassium ion gel electrolyte exhibits good interfacial adhesion, potassium metal affinity, and ion transport performance, and can be widely used in the field of potassium ion batteries. Attached Figure Description

[0023] 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 some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0024] Figure 1 This is a SEM image of the interfacially bonded potassium ion gel electrolyte prepared in Example 1 of the present invention.

[0025] Figure 2 The charge-discharge curves of the interfacially bonded potassium ion gel electrolyte prepared in Example 1 of this invention when used in a potassium ion battery.

[0026] Figure 3 The cycling curve of the interfacially bonded potassium ion gel electrolyte prepared in Example 1 of this invention when used in a potassium ion battery.

[0027] Figure 4 The charge-discharge curves are for comparative example 1, where the liquid electrolyte is used in a potassium-ion battery.

[0028] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0029] The technical solutions described below in conjunction with the embodiments will be clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the 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.

[0030] The main objective of this invention is to propose an interfacially adherent potassium ion gel electrolyte and its preparation method, which has the following advantages:

[0031] 1) The preparation method described in this invention is simple, has a short production cycle, and is easy to operate.

[0032] 2) The interfacial adhesion gel electrolyte prepared by this invention effectively prevents the electrolyte leakage problem present in liquid potassium-ion batteries. Based on the good interfacial adhesion characteristics of the prepared gel electrolyte, the interfacial stability between the electrolyte and potassium metal is enhanced, and the generation of dead potassium is effectively suppressed.

[0033] 3) This invention is the first to synthesize a potassium ion gel electrolyte with interfacial adhesion properties by copolymerizing soft and hard organic polymer monomers (soft monomer butyl acrylate and hard monomer methyl methacrylate).

[0034] The technical solution of the present invention will be further described below with reference to specific embodiments.

[0035] Example 1

[0036] A method for preparing an interfacially adherent potassium ion gel electrolyte includes the following steps:

[0037] S1. Add 0.03g of azobisisobutyronitrile to 5g of potassium ion electrolyte and stir until dissolved to obtain the electrolyte precursor.

[0038] S2. Mix 0.428g of butyl acrylate and 2.571g of methyl methacrylate evenly to obtain a gel electrolyte polymer precursor;

[0039] S3. Mix the electrolyte precursor and the gel electrolyte polymer precursor evenly and stir for 30 min to prepare the gel electrolyte precursor. Then place the gel electrolyte precursor in a mold and thermally polymerize at 40℃ for 6 h to obtain the interfacially adhered potassium ion gel electrolyte.

[0040] The SEM surface image of the interfacially bonded potassium ion gel electrolyte prepared in this embodiment is shown below. Figure 1 As shown, the prepared gel electrolyte has a smooth surface without particles, indicating that the polymerized electrolyte is uniform and transparent, which is more conducive to electrode adhesion.

[0041] Inside a glove box, using 3,4,9,10-perylenetetracarboxylic dianhydride as the positive electrode and a potassium metal sheet as the negative electrode, the interfacially bonded potassium ion gel electrolyte prepared as described in Example 1 was assembled into a coin cell between the positive and negative electrodes. The assembled solid-state potassium ion battery was subjected to constant current charge-discharge testing on a Neware battery tester, with the current density set to 100 mA g. ‑1 The test voltage range is 1.5~3.5V, and the charge / discharge curve is as follows: Figure 2 As shown, the discharge specific capacity is 134 mAh g. -1 The cyclic curve is as follows: Figure 3 As shown, the semi-solid-state battery assembled based on the adhesive potassium ion gel can achieve stable cycling for 1000 cycles, exhibiting excellent electrochemical performance.

[0042] Comparative Example 1

[0043] To visually demonstrate the impact of gel electrolytes and liquid electrolytes on the performance of potassium-ion batteries, a mixture of 1M KFSI in ethylene carbonate and diethyl carbonate was used as the electrolyte. Using the same positive and negative electrodes as in Example 1, the assembled liquid potassium-ion battery was subjected to a constant current charge-discharge test on a Neware battery tester, with the current density set to 100 mAg. -1 The test voltage range is 1.5~3.5V, and the charge / discharge curve is as follows: Figure 4 As shown. The discharge specific capacity is 127 mAh g. -1 Furthermore, it exhibits greater polarization.

[0044] This invention involves adding azobisisobutyronitrile (AIBN) to a potassium ion electrolyte and stirring until dissolved to obtain an electrolyte precursor. Butyl acrylate and methyl methacrylate are then uniformly mixed to obtain a gel electrolyte polymer precursor. The electrolyte precursor and the gel electrolyte polymer precursor are then uniformly mixed and stirred to prepare a gel electrolyte precursor. Subsequently, the gel electrolyte precursor is placed in a mold for thermal polymerization to obtain an interfacially adhered potassium ion gel electrolyte. This invention features a short production cycle, low cost, and simple operation. The prepared interfacially adhered potassium ion gel electrolyte exhibits good interfacial adhesion, potassium metal affinity, and ion transport performance, and can be widely used in the field of potassium ion batteries.

[0045] The above description is merely a preferred embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural transformations made using the contents of the present invention under the inventive concept of the present invention, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present invention.

Claims

1. A method for preparing an interfacially adherent potassium ion gel electrolyte, characterized in that, Includes the following steps: S1. Add 0.03g of azobisisobutyronitrile to 5g of potassium ion electrolyte and stir until dissolved to obtain the electrolyte precursor. S2. Mix 0.428g of butyl acrylate and 2.571g of methyl methacrylate evenly to obtain a gel electrolyte polymer precursor; S3. Mix the electrolyte precursor and the gel electrolyte polymer precursor evenly and stir for 30 min to prepare the gel electrolyte precursor. Then place the gel electrolyte precursor in a mold and thermally polymerize at 40℃ for 6 h to obtain the interfacially adhered potassium ion gel electrolyte. Inside a glove box, a coin cell was assembled using 3,4,9,10-perylenetetracarboxylic dianhydride as the positive electrode and a potassium metal sheet as the negative electrode, with an interfacially bonded potassium ion gel electrolyte placed between the positive and negative electrodes. The assembled solid-state potassium-ion battery was then subjected to constant current charge-discharge testing on a Neware battery tester, with the current density set to 100 mA g. -1 The test voltage range was 1.5~3.5V, and the discharge specific capacity was 134 mAh g. -1 The semi-solid-state battery assembled based on the adhesion of potassium ion gel can achieve stable cycling for 1000 cycles.

2. The method for preparing interfacially adhered potassium ion gel electrolyte according to claim 1, characterized in that, In step S1, the potassium ion electrolyte includes a potassium salt and an organic solvent, wherein the potassium salt is KFSI and the organic solvent is ethylene carbonate and diethyl carbonate.

3. An interfacially adherent potassium ion gel electrolyte, characterized in that, It was prepared using the method for preparing interfacially bonded potassium ion gel electrolyte according to any one of claims 1-2.

4. A potassium-ion battery, characterized in that, The interfacially bonded potassium ion gel electrolyte as described in claim 3 is assembled between the positive electrode and the negative electrode.

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