CN111509307B

CN111509307B - Preparation method and application of inorganic colloid electrolyte of water-based zinc ion battery

Info

Publication number: CN111509307B
Application number: CN202010322909.4A
Authority: CN
Inventors: 梁叔全; 解雪松; 邢振月; 周江
Original assignee: Central South University
Current assignee: Central South University
Priority date: 2020-04-22
Filing date: 2020-04-22
Publication date: 2023-08-15
Anticipated expiration: 2040-04-22
Also published as: CN111509307A

Abstract

The invention discloses a preparation method and application of an inorganic colloidal electrolyte of a water-based zinc ion battery, comprising the following steps: 1) Immersing calcium hydroxy phosphate into zinc salt solution, carrying out ion exchange treatment, filtering and drying after the treatment is finished to obtain inorganic powder; 2) Grinding inorganic powder, mixing with conventional liquid electrolyte, uniformly mixing, and pressing into slices with set thickness to obtain the inorganic colloid electrolyte. The invention utilizes inorganic matters in the mixed form of the zinc hydroxy phosphate and the calcium hydroxy phosphate, which are obtained after the ion exchange of calcium ions and zinc ions in the calcium hydroxy phosphate, and only needs to be mixed with a small amount of conventional liquid electrolyte and then pressed to obtain the colloidal electrolyte, thereby not only playing a role in isolating positive and negative electrodes, but also reducing the amount of active water, relieving the side reaction of water decomposition, avoiding capacity attenuation, ensuring higher specific capacity and cycle stability, having simple preparation process, safety and no toxicity, and having application prospect in the field of developing high-stability colloidal zinc ion batteries.

Description

Preparation method and application of inorganic colloid electrolyte of water-based zinc ion battery

Technical Field

The invention belongs to the technical field of preparation of colloidal electrolytes of water-based zinc ion batteries, and particularly relates to a preparation method and application of an inorganic colloidal electrolyte of a water-based zinc ion battery.

Background

In recent years, zinc ion batteries have been developed due to the high theoretical capacity of metallic zinc (820 mA.h.g ^-1 ) The energy storage device has the outstanding advantages of abundant reserves, safety, green, no toxicity and the like, and is widely focused by people, thereby having potential application value in the field of large-scale energy storage. The electrolyte is one of important components in the battery composition, and most of the electrolytes of zinc ion batteries are water-based liquid electrolytes nowadays, wherein a large amount of active water can cause a plurality of side reactions, such as hydrogen evolution, corrosion, passivation and the like, and further cause the phenomena of capacity attenuation, low coulombic efficiency, short circuit and the like of the zinc ion batteries, and meanwhile, the dissolution of a positive electrode material in water is also an important cause of the battery performance attenuation, which severely restricts the development of the water-based zinc ion batteries.

Therefore, a plurality of scientific researchers aim at the direction of the electrolyte, and the problems can be relieved by optimizing the electrolyte, so that the performance of the zinc ion battery is improved. For example, the water in salt electrolyte, the high-concentration electrolyte solution can effectively inhibit the interaction between zinc ions and water molecules, so that side reactions are avoided, but the use of a large amount of zinc salts also increases the cost, and is not suitable for practical application. The colloidal electrolyte has potential development prospect due to the fact that the colloidal electrolyte contains limited active water and good ionic conductivity, meanwhile, the problem of electrolyte leakage after battery breakage can be effectively solved, the currently reported colloidal electrolyte is mostly prepared by utilizing plasticization between a polymer and a solvent, but the polymer is easy to generate structural recombination and high in crystallization, so that the ionic conductivity and the battery life are reduced. The invention provides an inorganic colloid electrolyte which can effectively avoid side reactions caused by active water.

Disclosure of Invention

The invention aims to provide a preparation method and application of an inorganic colloid electrolyte of a water-based zinc ion battery, which can not only avoid side reactions caused by active water, but also maintain excellent ion conductivity and electrochemical stability, and has good application prospect in the water-based zinc ion battery.

The preparation method of the inorganic colloid electrolyte of the water-based zinc ion battery comprises the following steps:

1) Immersing calcium hydroxy phosphate into zinc salt solution, carrying out ion exchange treatment, filtering and drying after the treatment is finished to obtain inorganic powder;

2) Grinding the inorganic powder in the step 1), mixing with a conventional liquid electrolyte, uniformly mixing, and pressing into a sheet with a set thickness to obtain the inorganic colloid electrolyte.

In the step 1), the zinc salt is one or more of zinc sulfate, zinc nitrate, zinc chloride, zinc triflate and zinc bis (trifluoromethylsulfonyl) imide, preferably one of zinc sulfate and zinc nitrate; the concentration of the zinc salt solution is 1-5 mol/L, preferably 2mol/L; the mass ratio of the calcium hydroxy phosphate to the zinc salt solution is (2-5) (8-12), the ion exchange treatment is one of ultrasonic treatment and standing treatment, the ultrasonic treatment time is 0.5-3 h, and the standing treatment time is 8-12 h; the drying temperature is 60-120 ℃ and the drying time is 8-12 h.

In the step 1), the inorganic powder is a mixture of zinc hydroxy phosphate and calcium hydroxy phosphate.

In the step 2), the inorganic powder accounts for 50-95% of the mass of the whole colloidal electrolyte, and the set thickness is 30 mu m-2 mm.

In the step 2), the conventional liquid electrolyte is formed by mixing zinc salt and functional metal salt; the zinc salt comprises one or more of zinc sulfate, zinc nitrate, zinc chloride, zinc triflate and zinc bis (trifluoromethylsulfonyl) imide, preferably zinc sulfate; the functional metal salt is one or more of manganese salt, sodium salt and potassium salt, preferably manganese sulfate; the concentration of the zinc salt is 1 to 3mol/L, preferably 2mol/L; the concentration of the functional metal salt is 0.05 to 1mol/L, preferably 0.1mol/L.

The inorganic colloid electrolyte is prepared according to the preparation method.

The inorganic colloid electrolyte is applied to zinc ion batteries.

The zinc ion battery comprises a zinc cathode, an inorganic colloid electrolyte and a manganese dioxide anode.

The principle of the invention is as follows: the calcium hydroxy phosphate belongs to a hexagonal system, is safe and nontoxic, has weak dissolution in water, has excellent biocompatibility and bioactivity, has important application in medical materials and adsorption materials, has rich ion exchange sites on the surface, and can be replaced by various metal ions through ion exchange reaction to form M apatite (M represents metal ions substituting calcium ions) corresponding to the metal ions.

The calcium hydroxy phosphate and the zinc salt solution are mixed and then undergo calcium-zinc ion exchange to obtain inorganic matters in the mixed form of the zinc hydroxy phosphate and the calcium hydroxy phosphate, so that the crystal structure of the original calcium hydroxy phosphate is maintained to a great extent. The inorganic powder and a small amount of conventional liquid electrolyte are mixed and pressed to obtain a colloidal electrolyte with a certain thickness, wherein the amount of active water is limited, and the common liquid leakage phenomenon of the liquid electrolyte and parasitic reaction of the active water are avoided; the radius of the replaced calcium ions is larger than that of the zinc ions, and the positions of the zinc ions are provided with larger movable spaces after ion exchange, so that a rapid migration channel can be formed, the migration rate of the zinc ions is improved, and the specific capacity of the battery is remarkably improved; in addition, the inorganic powder retains rich ion exchange sites, the high activity of the exchange sites in the battery cycle can enable zinc ions to rapidly migrate through ion exchange, and the excellent thermal stability and biocompatibility of the inorganic powder can greatly widen the application range of the electrolyte.

The invention has the beneficial effects that:

(1) The invention utilizes inorganic matters in the mixed form of zinc hydroxy phosphate and calcium hydroxy phosphate, which are obtained after the ion exchange of calcium ions and zinc ions in the calcium hydroxy phosphate, and only needs to be mixed with a small amount of conventional liquid electrolyte and then pressed to obtain the colloidal electrolyte, thereby not only playing a role in isolating positive and negative electrodes, but also relieving side reactions such as hydrogen evolution, oxygen evolution and the like, avoiding capacity attenuation and ensuring higher specific capacity and cycle stability due to the reduction of the active water quantity.

(2) After the calcium ions in the hydroxyl calcium phosphate are replaced by the zinc ions, the radius of the calcium ions is larger than that of the zinc ions, and the zinc ions are positioned at the original calcium ion sites after ion exchange, so that the hydroxyl calcium phosphate has loose activity space, can form a rapid migration channel of the zinc ions, improves the diffusion rate of the zinc ions, and optimizes the battery performance.

(3) The ion-exchanged inorganic powder of the invention maintains the original crystal structure to a great extent, retains rich ion exchange sites, realizes the rapid transmission of zinc ions through ion exchange in the battery cycle process, and improves the specific capacity of the battery.

(4) The invention has the advantages of abundant and easily obtained raw material sources, no toxicity, no pollution to the environment, low cost, simple preparation process, easy implementation and mass production. The electrolyte has good biocompatibility and thermal stability, and can be applied to electric devices in organisms.

Drawings

Fig. 1 shows a performance diagram of the zinc-ion battery prepared in comparative example 1, (a) a cycle performance diagram of the battery; (b) partial charge-discharge curve graph.

FIG. 2 shows a graph of the performance of the zinc-ion cell prepared in comparative example 2, (a) a graph of the cycle performance of the cell; (b) partial charge-discharge curve graph.

Figure 3 XRD pattern of inorganic powder prepared in example 1.

Fig. 4 is a schematic diagram showing the assembly of the inorganic powder and the zinc ion battery in example 1.

Fig. 5 shows a performance diagram of the zinc-ion battery prepared in example 1, (a) a cycle performance diagram of the battery; (b) partial charge-discharge curve graph.

Fig. 6 shows a performance diagram of the zinc-ion battery prepared in example 2, (a) a cycle performance diagram of the battery; (b) partial charge-discharge curve graph.

Fig. 7 shows a performance diagram of the zinc-ion battery prepared in example 3, (a) a cycle performance diagram of the battery; (b) partial charge-discharge curve graph.

Detailed Description

Comparative example 1

Proper amounts of zinc sulfate and manganese sulfate were weighed and dissolved in deionized water to prepare a liquid electrolyte having a concentration of 2mol/L zinc sulfate+0.1 mol/L manganese sulfate as a conventional liquid electrolyte of this comparative example. And (3) taking a manganese dioxide pole piece as an anode, a zinc piece as a cathode and glass fiber as a diaphragm, and assembling the CR2016 type button battery according to a conventional method. The electrochemical performance of the battery is tested in the LAND test system, the test voltage range of the battery is 0.85-1.8V, and the charge-discharge current density is 0.5A g ^-1 The cycle performance map and partial charge-discharge curve of fig. 1 were obtained.

FIG. 1a is a graph of the cycle performance of this comparative example, with an initial specific capacity of only 106mA h g ^-1 After that, the activation capacity is slowly increased, but the highest specific volume is only 126mA h g ^-1 And the cycle stability is poor because the cycle stability is in a descending trend after 40 cycles. Fig. 1b is a partial charge-discharge graph with an obvious charge-discharge plateau.

Comparative example 2

Weighing proper amounts of zinc sulfate and manganese sulfate, dissolving in deionized water to prepare a liquid electrolyte with the concentration of 2mol/L zinc sulfate plus 0.1mol/L manganese sulfate, directly adding calcium hydroxy phosphate powder (accounting for 60% of the mass of the colloidal electrolyte according to the calcium hydroxy phosphate powder) into the liquid electrolyte, uniformly mixing, and pressing to obtain the colloidal electrolyte with the thickness of 0.5 mm. The colloidal electrolyte prepared in the comparative example is adopted, the manganese dioxide anode and the zinc sheet cathode are assembled into the CR2016 button battery, and a glass fiber diaphragm is not needed to separate the anode from the cathode. The electrochemical performance was measured using the LAND test system using the same current density and voltage intervals as comparative example 1 to obtain the cycling performance of fig. 2a and the partial charge-discharge curve of fig. 2 b.

As can be seen from fig. 2a, at 0.5. 0.5A g ^-1 The initial specific capacity is 156mA h g under the current density and the voltage interval of 0.85-1.8V ^-1 After 100 cycles, the product is 92mA h g ^-1 The capacity retention was only 58% and the capacity fade was severe. As can be seen from fig. 2b, there is no obvious charging plateau in the charge-discharge curve, but a smoother arc, and the arc starting point has no tip, which indicates that serious polarization of the battery occurs, and the zinc deposition energy barrier is higher, which may cause serious zinc dendrite.

Example 1

Solution preparation: (1) zinc sulfate is dissolved in deionized solution to prepare 2mol/L zinc sulfate; (2) zinc sulfate and manganese sulfate are dissolved in deionized water to prepare 2mol/L zinc sulfate+0.1 mol/L manganese sulfate liquid electrolyte.

Adding calcium hydroxy phosphate into 2mol/L zinc sulfate solution according to the mass ratio of 3:10, mixing, standing for 12h, performing full calcium-zinc ion exchange reaction, performing suction filtration, and drying a filter cake at 80 ℃ for 12h to obtain inorganic powder;

grinding inorganic powder into fine powder in a mortar, adding the fine powder into liquid electrolyte according to the mass of the inorganic powder accounting for 60 percent of the electrolyte, uniformly mixing, and pressing into a sheet with the thickness of 0.5mm to obtain the inorganic colloid electrolyte.

The inorganic powder and calcium hydroxy phosphate prepared in this example were characterized by using an X-ray diffractometer, the scanning range was 5 to 80℃and the scanning speed was 10℃per minute, and the results are shown in FIG. 3.

As can be seen from fig. 3, after mixing the calcium hydroxy phosphate with the liquid electrolyte, ion exchange occurs, part of calcium ions are replaced by zinc ions, and the comparison of peak positions and relative intensities can show that the mixture after ion exchange approximately retains the crystal structure of the calcium hydroxy phosphate, has rich ion exchange sites, has good thermal stability and can provide higher conductivity.

The colloidal electrolyte prepared in this example was used to assemble CR2016 button cell (see FIG. 4 for specific assembly structure) at 0.5. 0.5A g for manganese dioxide positive electrode and zinc plate negative electrode ^-1 The electrochemical properties were measured using a LAND test system at a current density and a voltage interval of 0.85 to 1.8V, to obtain the graph shown in fig. 5.

FIG. 5a is a graph showing the cycle performance of the gel electrolyte assembled zinc ion battery of this example, the specific capacity of the second cycle being 220mA h g ^-1 The specific capacity after 100 cycles is 202mA h g ^-1 The capacity retention rate was 92%, and the specific capacity of this example was greatly improved as compared with comparative examples 1 and 2. Fig. 5b shows a partial charge-discharge curve, and it can be seen that there is an obvious charging plateau, and a tip exists at the beginning of the plateau, which indicates that the zinc deposition energy barrier is lower, and zinc ions can be promoted to be uniformly deposited.

Example 2

The method for preparing the colloidal electrolyte of this example was substantially the same as that of example 1, except that the thickness of the colloidal electrolyte used for assembling the zinc-ion battery was 0.8mm, and the CR2016 button battery was assembled together with the manganese dioxide positive electrode and the zinc sheet negative electrode, at 0.5A g ^-1 The electrochemical performance was measured using a LAND test system at a current density and a voltage interval of 0.85 to 1.8V, to obtain a cycle performance chart and a partial charge-discharge graph of fig. 6.

FIG. 6a is a graph showing the cycle performance of a zinc ion battery assembled with the colloidal electrolyte of the present example, with an initial specific volume of 163mA h g ^-1 After 100 cycles, the specific capacity is 164mA h g ^-1 The curve is basically horizontal, and compared with the example 1, the thickness of the colloidal electrolyte is increased, so that the cycling stability of the zinc ion battery can be effectively improved, and the service life of the battery can be prolonged.

Example 3

Adding calcium hydroxy phosphate into a 2mol/L zinc sulfate solution according to the mass ratio of 3:10, mixing, performing ultrasonic treatment for 2 hours, performing full calcium-zinc ion exchange reaction, performing suction filtration, and drying a filter cake at 80 ℃ for 12 hours to obtain inorganic powder;

The gel electrolyte prepared in this example was used as the positive electrode of manganese dioxide and the negative electrode of zinc sheet to assemble CR2016 button cell, at 0.5. 0.5A g ^-1 The electrochemical performance was measured using the LAND test system at the current density and voltage interval of 0.85-1.8V to obtain the cycle performance graph and partial charge-discharge graph of fig. 7.

FIG. 7a is a graph showing the cycle performance of a zinc ion battery assembled with the colloidal electrolyte of the present example, the initial specific volume being 216mA h g ^-1 The specific capacity is 160mA h g after 100 circles of circulation ^-1 The capacity retention was only 76%, and although the colloidal electrolyte obtained by the ultrasonic treatment still had a higher specific capacity, the ultrasonic treatment damaged the material structure to some extent, resulting in serious capacity fading, as compared with example 1.

Claims

1. The preparation method of the inorganic colloid electrolyte of the water-based zinc ion battery comprises the following steps:

the concentration of the zinc salt solution is 1-5 mol/L, the mass ratio of the calcium hydroxy phosphate to the zinc salt solution is (2-5): (8-12), the ion exchange treatment is one of ultrasonic treatment and standing treatment, the ultrasonic treatment time is 0.5-3 h, and the standing treatment time is 8-12 h; the inorganic powder consists of zinc hydroxy phosphate and calcium hydroxy phosphate;

in the step 1), the zinc salt is one or more of zinc sulfate, zinc nitrate, zinc chloride, zinc triflate and bis (trifluoromethyl sulfonyl) imide zinc; the drying temperature is 60-120 ℃, and the drying time is 8-12 hours;

2) Grinding the inorganic powder in the step 1), mixing with a conventional liquid electrolyte, uniformly mixing, and pressing into a sheet with a set thickness to obtain an inorganic colloid electrolyte;

2. The method for producing an inorganic colloidal electrolyte for a water-based zinc ion battery according to claim 1, wherein the zinc salt is one of zinc sulfate and zinc nitrate; the concentration of the zinc salt solution is 2mol/L.

3. The method for preparing inorganic colloidal electrolyte of aqueous zinc ion battery according to claim 1, wherein in the step 2), the conventional liquid electrolyte is formed by mixing zinc salt and functional metal salt; the zinc salt is one or more of zinc sulfate, zinc nitrate, zinc chloride, zinc triflate and bis (trifluoromethylsulfonyl) imide zinc, the functional metal salt is one or more of manganese salt, sodium salt and potassium salt, the concentration of the zinc salt is 1-3 mol/L, and the concentration of the functional metal salt is 0.05-0.5 mol/L.

4. The method for producing an inorganic colloidal electrolyte for an aqueous zinc-ion battery according to claim 3, wherein the zinc salt is zinc sulfate; the functional metal salt is manganese sulfate; the concentration of zinc salt is 2mol/L; the concentration of the functional metal salt is 0.1mol/L.

5. The inorganic colloidal electrolyte prepared by the preparation method according to any one of claims 1 to 4.

6. Use of the inorganic colloidal electrolyte according to claim 5 in a zinc ion battery.

7. The zinc-ion battery of claim 6 comprising a zinc anode, an inorganic colloidal electrolyte, and a manganese dioxide cathode.