A method for interlayer environment regulation of MXene electrode for ion battery

Abstract

The application is suitable for the field of zinc ion batteries, and provides a method for interlayer environment regulation of MXene electrode of ion battery, which comprises the following steps: 150 mL of 3M ferric chloride solution is uniformly mixed with multilayer V2CTx precipitate, and then the mixture is evenly divided into three parts and respectively loaded into reaction kettles; the liquid is heated in an environment with a temperature of 50 DEG C, 100 DEG C, 150 DEG C, 200 DEG C and 250 DEG C respectively; the liquid is cooled at room temperature, and the ink green solution generated in the three reaction kettles is poured out after cooling, the liquid in the reaction kettle is centrifuged for 5 minutes, and then the supernatant is poured out; 75% concentration of ethanol is respectively added to the three samples, and ultrasonic treatment is carried out for 30 minutes by using an ultrasonic machine with a power of 750W, the obtained precipitate is V2CTx embedded with Fe nanoparticles at different temperatures, the precipitate is placed in a vacuum drying box and vacuum dried in a temperature environment of 80 DEG C, and then the precipitate is ground to be free of obvious particles and vacuum packaged.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of zinc ion batteries, and particularly relates to a method for regulating the interlayer environment of an MXene electrode for ion batteries. BACKGROUND

[0002] The huge consumption of non-renewable fossil energy by human beings has led to the gradual depletion of fossil energy and also brought about serious environmental problems, such as the enhancement of greenhouse effect and global warming caused by greenhouse gas emission, which seriously affect the global ecological environment. In order to avoid the premature depletion of global fossil energy, it is particularly important to develop and utilize renewable and clean energy and better energy storage systems. Although solar and wind energy can provide a large amount of output, they are seriously dependent on environmental conditions, which makes it difficult to control the daily energy output. Therefore, it is necessary to develop and construct large-scale energy storage facilities and portable mobile energy storage devices to effectively solve these problems to some extent.

[0003] A battery is a popular energy storage device with high-efficiency energy storage means, and how to design and develop a more safe and reliable battery with cost-effectiveness has thus become one of the current research hotspots. In the development process of batteries, various batteries with zinc metal as the negative electrode, such as zinc-manganese batteries, nickel-zinc batteries and zinc-air batteries, have been widely researched and developed. At present, there are mainly two rechargeable aqueous zinc ion battery systems, namely alkaline and neutral systems. The energy storage mechanism of the alkaline zinc ion battery is the reversible chemical reaction of the positive material and the zinc foil negative electrode with OH-. Usually, a foam nickel is used as the current collector, a potassium hydroxide and zinc salt mixed aqueous solution is used as the electrolyte, a transition metal oxide is used as the positive electrode, and a zinc foil is used as the negative electrode to prepare the alkaline zinc ion battery. However, the stability of this battery system is poor due to the serious corrosion of the zinc negative electrode during the cycle process. The neutral aqueous zinc ion battery has attracted widespread attention due to its more excellent electrochemical performance, and its rocking chair structure is also similar to that of the lithium battery.

[0004] At present, the research on zinc ion batteries mainly focuses on the development of positive electrode materials with excellent Zn2+ ion storage capacity. Common zinc ion battery positive electrode materials include manganese-based oxides, prussian blue analogues, vanadium-based oxides and polymer materials. However, the existing positive electrode materials generally have the problem of low electronic / ionic conductivity, which leads to the problems of poor rate performance and low discharge capacity of zinc ion batteries. Therefore, exploring zinc ion positive electrode materials with high theoretical specific capacity, high conductivity and good stability is the key to fully exert the advantages of aqueous zinc ion batteries and promote their application in various fields.

[0005] There are few studies on MXene as a positive electrode material for zinc ion batteries. However, the accordion-like MXene has a high-conductive two-dimensional layered structure, which can theoretically realize the rapid embedding and extraction of Zn2+, and is a reasonable choice for preparing high-rate zinc ion batteries. V2CTX, as a member of the MXene family, has the advantages of intrinsic high conductivity, and the V element has the ability to change the valence state, which can theoretically provide high specific capacity of electrochemical zinc storage. SUMMARY

[0006] The purpose of the embodiment of the present application is to provide a method for interlayer environment regulation of MXene electrode for ion battery, aiming to solve the problem that V2CTx MXene is prone to interlayer stacking or collapse during the cycle process, resulting in unsatisfactory electrochemical performance.

[0007] The embodiment of the present application is implemented in this way, a method for interlayer environment regulation of MXene electrode for ion battery, the method for interlayer environment regulation of MXene electrode for ion battery comprises the following steps:

[0008] Step one, prepare 150 mL of 3M ferric chloride solution and mix it evenly with multi-layer V2CTX precipitate, and divide it into three parts and put it into the reaction kettle respectively;

[0009] Step two, heat the liquid in step one at 50℃, 100℃, 150℃, 200℃ and 250℃ respectively;

[0010] Step three, cool the liquid in step two at room temperature, and after cooling, pour out the dark green solution generated in the three reaction kettles, and centrifuge the liquid in the reaction kettle for 5 minutes, and then pour off the supernatant.

[0011] Step four, add appropriate amount of 75% concentration of ethanol to the three samples, and ultrasonically treat them with an ultrasonic machine with a power of 750W for 30 minutes, and the obtained precipitate is V2CTX embedded with Fe nanoparticles at different temperatures,

[0012] Step five, place the precipitate obtained in step four in a vacuum drying oven and vacuum dry it at a temperature of 80℃, and grind it to no obvious particles, and vacuum package it.

[0013] As a further scheme of the present application, the liquid in step one is heated at 50℃, 100℃, 150℃, 200℃ and 250℃ respectively, and the heating time is not less than 12h.

[0014] As a further scheme of the present application, the liquid in the reaction kettle is centrifuged in step three, and the centrifugal speed is 5000r / min.

[0015] As a further scheme of the present application, the vacuum drying at a temperature environment of 80 DEG C in step five, wherein the time of vacuum drying is not less than 12h.

[0016] The method for interlayer environment regulation of MXene electrode for ion battery provided by the embodiment of the present application has the following beneficial effects:

[0017] The present application embeds Fe nanoparticles into the interlayer of V2CTx MXene at different temperatures by hydrothermal method to construct two-dimensional heterostructure, and the Fe nanoparticles embedded in the interlayer act as column support structure, which widens the channel for zinc ion transport and provides more active sites, thereby improving the cycle stability and capacity. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 XRD spectrum of Fe nanoparticles pre-embedded V2CTx MXene at 50 DEG C based on hydrothermal synthesis;

[0019] Figure 2 Cycle stability graph of Fe nanoparticles pre-embedded V2CTx MXene at 50 DEG C based on hydrothermal synthesis;

[0020] Figure 3 XRD spectrum of Fe nanoparticles pre-embedded V2CTx MXene at 100 DEG C based on hydrothermal synthesis;

[0021] Figure 4 Cycle stability graph of Fe nanoparticles pre-embedded V2CTx MXene at 100 DEG C based on hydrothermal synthesis;

[0022] Figure 5 XRD spectrum of Fe nanoparticles pre-embedded V2CTx MXene at 200 DEG C based on hydrothermal synthesis;

[0023] Figure 6 Cycle stability graph of Fe nanoparticles pre-embedded V2CTx MXene at 200 DEG C based on hydrothermal synthesis. EMBODIMENT

[0024] In order to make the purpose, technical scheme and advantages of the present application more clear, the present application is further described in detail below in combination with the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application, and are not used to limit the present application.

[0025] The specific implementation of the present application is described in detail below in combination with specific embodiments.

[0026] A method for interlayer environment regulation of an ion battery-oriented MXene electrode layer, comprising the following steps:

[0027] Step one, 150 mL of 3M ferric chloride solution is mixed with multilayer V2CTx precipitate, and evenly divided into three parts and loaded into reaction kettles;

[0028] Step two, the liquid in step one is heated in a temperature environment of 50 DEG C, 100 DEG C, 150 DEG C, 200 DEG C and 250 DEG C respectively;

[0029] Step three, the liquid in step two is cooled at room temperature, and the dark green solution generated in the three reaction kettles is poured out after cooling, and the liquid in the reaction kettle is centrifuged for 5 minutes, and then the supernatant is poured out.

[0030] Step four, an appropriate amount of 75% concentration of ethanol is added to the three samples, and ultrasonic treatment is carried out for 30 minutes by using an ultrasonic machine with a power of 750W, and the obtained precipitate is V2CTx embedded with Fe nanoparticles at different temperatures,

[0031] Step five, the precipitate obtained in step four is placed in a vacuum drying box and vacuum dried at a temperature environment of 80 DEG C, and ground to no obvious particles, and vacuum packaged.

[0032] In the embodiment of the present application, the liquid in step one is heated in a temperature environment of 50 DEG C, 100 DEG C, 150 DEG C, 200 DEG C and 250 DEG C, and the heating time is not less than 12h.

[0033] In the embodiment of the present application, the liquid in the reaction kettle is centrifuged in step three, and the centrifugal speed is 5000r / min.

[0034] In the embodiment of the present application, the vacuum drying at a temperature environment of 80 DEG C in step five is carried out for not less than 12h.

[0035] Example 1

[0036] Prepare 150 mL of 3M ferric chloride solution and mix it with multilayer V2CTx precipitate, and evenly divide it into three parts and load it into reaction kettles. Heat at 50 DEG C for more than 12h. After cooling at room temperature, pour out the dark green solution generated in the three reaction kettles, centrifuge for 5 minutes at a speed of 5000r / min, and then pour out the supernatant. An appropriate amount of 75% concentration of ethanol is added to the three samples, and ultrasonic treatment is carried out for 30 minutes by using an ultrasonic machine with a power of 750W, and the obtained precipitate is V2CTx embedded with Fe nanoparticles at different temperatures, which is vacuum dried at 80 DEG C for more than 12h in a vacuum drying box, and then ground to no obvious particles and vacuum packaged.

[0037] Figure 1 For the XRD pattern of Fe nanoparticles pre-embedded in V2CTx MXene at 50°C based on hydrothermal synthesis, it can be observed that the spectrum of Fe nanoparticles embedded in V2CTx MXene all appeared (002) and (006) peaks, which is consistent with the XRD spectrum of V2CTx MXene reported in other literatures. The results show that the embedding of Fe nanoparticles does not change the crystal structure of V2CTx MXene. The (002) peak of the embedded Fe nanoparticles is all slightly shifted to the right at a small angle. The interlayer distance of V2CTx MXene and V2CTx MXene embedded with Fe nanoparticles at different temperatures is calculated to be 10.028 Å by Bragg equation (2dsinθ=nλ). Figure 1

[0038] Figure 2 For the cyclic characteristic curve of Fe nanoparticles pre-embedded in V2CTx MXene electrode at 50°C based on hydrothermal synthesis at a current density of 100 mA / g, a three-electrode system was used to test the cycle characteristics of aqueous zinc ion battery. As can be seen from the figure, the specific capacity of the original V2CTx MXene electrode is low, and the first discharge specific capacity is 13.9 mAh / g. After 100 cycles, the remaining capacity is 40.6 mAh / g. While the V2CTx MXene electrode pre-embedded with Fe nanoparticles at 50°C obtains the highest capacity, the first discharge capacity is 74.5 mAh / g, and the discharge capacity is 120.3 mAh / g after 100 cycles, which is increased by 61.48%. This is mainly due to the fact that the interlayer distance of V2CTx MXene electrode is increased after embedding Fe nanoparticles at 50°C, which in turn promotes the subsequent embedding and extraction process of Zn2+ in the electrolyte.

[0039] Implementation Example 2

[0040] A 3M ferric chloride solution of 150 mL was mixed with the multilayer V2CTx precipitate, and the mixture was evenly divided into three parts and loaded into a reaction kettle. Heating was carried out at 100°C for 12h or more. After cooling at room temperature, the dark green solution generated in the three reaction kettles was poured out, centrifuged for 5 minutes at a speed of 5000r / min, and the supernatant was discarded. Appropriate amount of 75% concentration of ethanol was added to the three samples, and ultrasonic treatment was carried out for 30 minutes with a power of 750W ultrasonic machine. The obtained precipitate was V2CTx embedded with Fe nanoparticles at different temperatures. After vacuum drying at 80°C in a vacuum drying box for 12h or more, it was ground to no obvious particles and vacuum packaged for use.

[0041] Figure 3 ​For the XRD pattern of Fe nanoparticles pre-embedded in V2CTx MXene at 100℃ based on hydrothermal synthesis, it can be observed that the spectrum of Fe nanoparticles embedded in V2CTx MXene appears (002) and (006) peaks, and the XRD spectrum of V2CTx MXene reported in other literatures Figure 1 The results show that the embedding of Fe nanoparticles does not change the crystal structure of V2CTx MXene. The (002) peak of the embedded Fe nanoparticles is shifted to the right at a small angle. The interlayer distance of V2CTx MXene and V2CTx MXene embedded with Fe nanoparticles at different temperatures is calculated to be 9.9631Å by Bragg equation (2dsinθ=nλ).

[0042] Figure 4 For the cyclic characteristic curve of the Fe nanoparticles pre-embedded in V2CTx MXene electrode at 100℃ based on hydrothermal synthesis, the water-based zinc ion battery was tested at a current density of 100mA / g using a three-electrode system.

[0043] Example 3

[0044] Prepare 150mL of 3M iron chloride solution and mix it evenly with the multilayer V2CTx precipitate, divide it into three equal parts and put it into the reaction kettle. Heat at 150℃ for 12h or more. After cooling at room temperature, pour out the dark green solution generated in the three reaction kettles, centrifuge for 5 minutes at a speed of 5000r / min, and then pour out the supernatant. Add an appropriate amount of 75% ethanol to each of the three samples, and ultrasonically treat them with a 750W ultrasonic machine for 30 minutes. The obtained precipitate is V2CTx embedded with Fe nanoparticles at different temperatures. After vacuum drying at 80℃ in a vacuum drying oven for 12h or more, grind it to no obvious particles, and vacuum package for use.

[0045] Example 4

[0046] Prepare 150mL of 3M iron chloride solution and mix it evenly with the multilayer V2CTx precipitate, divide it into three equal parts and put it into the reaction kettle. Heat at 200℃ for 12h or more. After cooling at room temperature, pour out the dark green solution generated in the three reaction kettles, centrifuge for 5 minutes at a speed of 5000r / min, and then pour out the supernatant. Add an appropriate amount of 75% ethanol to each of the three samples, and ultrasonically treat them with a 750W ultrasonic machine for 30 minutes. The obtained precipitate is V2CTx embedded with Fe nanoparticles at different temperatures. After vacuum drying at 80℃ in a vacuum drying oven for 12h or more, grind it to no obvious particles, and vacuum package for use.

[0047] Figure 5For the XRD spectrum of Fe nanoparticles pre-embedded in V2CTx MXene based on hydrothermal synthesis at 200℃, it can be observed that the spectrum of Fe nanoparticles embedded in V2CTx MXene appears (002) and (006) peaks, and the XRD spectrum of V2CTx MXene reported in other literatures Figure 1 The results show that the embedding of Fe nanoparticles does not change the crystal structure of V2CTx MXene. The (002) peak of the embedded Fe nanoparticles is shifted to the right at a small angle. The interlayer distance of V2CTx MXene and V2CTx MXene embedded with Fe nanoparticles at different temperatures is calculated to be 9.6691 Å by Bragg equation (2dsinθ=nλ).

[0048] Figure 6 For the cyclic characteristic curve of Fe nanoparticles pre-embedded in V2CTx MXene electrode based on hydrothermal synthesis at 200℃, a three-electrode system was used to test the cycle characteristics of aqueous zinc ion battery at a current density of 100mA / g.

[0049] Example 5

[0050] A 3M ferric chloride solution of 150mL was mixed with the multilayer V2CTx precipitate uniformly, and divided into three equal parts and loaded into the reaction kettle. Heat at 250℃ for 12h or more. After cooling at room temperature, the dark green solution generated in the three reaction kettles was poured out, centrifuged for 5 minutes at a speed of 5000r / min, and the supernatant was discarded. Appropriate amount of 75% concentration of ethanol was added to the three samples, and ultrasonic treatment was carried out for 30 minutes with a power of 750W ultrasonic machine. The obtained precipitate was V2CTx embedded with Fe nanoparticles at different temperatures, which was dried in a vacuum drying oven at 80℃ for 12h or more, ground to no obvious particles, and vacuum packaged for use.

[0051] The above only describes the preferred embodiments of the present application and is not intended to limit the present application. Any modification, equivalent replacement and improvement within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method for interlayer environment regulation of MXene electrode for ionic batteries, characterized in that The method for regulating the interlayer environment of the MXene electrode layer for ion batteries comprises the following steps: Step one, prepare 150 mL of 3M ferric chloride solution and mix it with the multilayer V2CTx precipitate, then divide it into three equal parts and put it into the reaction kettle; Step two, heat the liquid in step one at temperatures of 50℃, 100℃, 150℃, 200℃, and 250℃ respectively; Step three, cool the liquid in step two at room temperature, and after cooling, pour out the dark green solution generated in the three reaction kettles, and centrifuge the liquid in the reaction kettle for 5 minutes, then pour out the supernatant; Step four, add 75% concentrated ethanol to each of the three samples, and ultrasonically treat them for 30 minutes with a power of 750W, then the obtained precipitate is V2CTx embedded with Fe nanoparticles at different temperatures; Step five, place the obtained precipitate in step four in a vacuum drying box and vacuum dry it at a temperature of 80℃, then grind it to no obvious particles, and vacuum package it, Further characterized in that the embedded Fe nanoparticles act as column support structures between the V2CTx layers to prevent the V2CTx from stacking or collapsing between the layers during the cycling process.

2. The method of ion-battery-oriented interlayer environment regulation of MXene electrode layers according to claim 1, characterized in that In step two, the liquid in step one is heated at temperatures of 50℃, 100℃, 150℃, 200℃, and 250℃ respectively, and the heating time is not less than 12 hours.

3. The method of ion-battery-oriented interlayer environment regulation of MXene electrode layers according to claim 1, characterized in that In step three, the liquid in the reaction kettle is centrifuged, and the centrifugal speed is 5000r / min.

4. The method of ion-battery-oriented interlayer environment regulation of MXene electrode layers according to claim 1, characterized in that In step five, the vacuum drying is carried out at a temperature of 80℃, and the vacuum drying time is not less than 12 hours.

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