CN110416535B - Preparation method of self-supporting NaxV2O5 nanowire sodium-ion battery array material - Google Patents

Abstract

The invention provides a high specific capacity self-supporting Na _x V₂O₅A method for preparing an (NVO) nanowire array. In particular to a method for cutting foamed nickel into 3 multiplied by 7 cm²The wafer of (1) was washed with dilute hydrochloric acid and then rinsed with a large volume of deionized water. The NVO nano-wire has the length of 1-3 μm, the width of 0.045-0.25 μm and the NVO active substance amount per unit area of 2-4 mg cm^‑2. The NVO nanowire array sodium ion battery negative plate takes ammonium metavanadate as a raw material, the pH value is adjusted to 2-4, then a chemical reaction is carried out under a hydrothermal condition, and V is obtained after annealing in air₂O₅And (3) carrying out heat treatment on the nanowire array by using high-concentration sodium hydroxide, and drying to obtain the nanowire array. The synthesis method of the sodium ion battery cathode material is simple, high-temperature annealing treatment is not needed, and energy consumption is low. The sodium ion half-cell assembled by the NVO nanowire negative plate has stable cycle performance and has potential application value in the field of sodium ion cells.

Description

Preparation method of self-supporting NaxV2O5 nanowire sodium-ion battery array material

Technical Field

The invention relates to a novel array type sodium ion battery material, in particular to self-supporting Na with a nanowire shape _x V₂O₅A nanowire sodium ion battery array material and a preparation method thereof belong to the field of sodium ion batteries.

Background

With the rapid development of rechargeable battery technology, the importance of lithium ion battery energy storage devices in people's daily life is increasing. At present, lithium ion batteries are mainly used in portable electronic devices and 3C products. With the advance of the policy of the state in the new energy industry, the lithium ion battery gradually shows the head in the transportation industry, but the cost problem caused by the shortage of lithium resources and the excessive rising price severely restricts the expansion of the lithium ion battery market. Therefore, alternatives to lithium ion batteries are urgently needed. The reserve of sodium element on the earth is far more than that of lithium, so that the research on the application of sodium ion batteries has important significance for solving the cost problem of lithium ion batteries. Recently, NVO (Na) _x V₂O₅，xNot more than 1) as a novel sodium ion battery anode material, the material starts to enter the visual field of researchers, has the advantages of high capacity, low cost, easy synthesis and the like, and has great potential application value. However, most of the currently reported NVO materials are limited toThe powder material is mainly used for anodes of lithium ion batteries and sodium ion batteries, and related research reports of the powder material for cathodes of the sodium ion batteries are rarely found, so that the powder material has important significance in deep research of applying the NVO nanowire array to anodes and cathodes of the sodium ion batteries. The patent discloses a method for preparing a self-supporting NVO nanowire array, and the loading capacity of the array material on a Ni current collector is 2-4 mg cm^-2And the Ni substrate is tightly contacted, so that the sodium ion battery assembled by the Ni substrate has stable electrochemical performance and high area specific capacity, and has great potential application value.

Disclosure of Invention

The invention aims to prepare V by taking ammonium metavanadate and hydrochloric acid as raw materials and Ni net as a substrate through hydrothermal reaction in a high-temperature and high-pressure environment₂O₅Further annealing in air to obtain V₂O₅Nanowire arrays, then V above by high concentration NaOH solution₂O₅Array for sodium ionization to prepare self-supporting Na _x V₂O₅Nanowire sodium ion battery array materials.

The raw materials of the invention are ammonium metavanadate, hydrochloric acid and sodium hydroxide. In the preparation process of the material, firstly, ammonium metavanadate is placed in a container, distilled water is added, and the mixture is placed in a container of 50-80 percent^oC, stirring in a water bath kettle, and after the solution is completely dissolved, dropwise adding the diluted hydrochloric acid solution to adjust the pH value of the solution to 2-4. Then transferring the solution into a hydrothermal reaction kettle and adding a treated Ni net at 150-200 DEG C^oC reacts for 10 to 24 hours to prepare V₂O₅Precursor 400-550 in air^oAnnealing to obtain V₂O₅And (4) array. Then V is put₂O₅The array was placed in NaOH solution at 150-^oAnd C, keeping for 10-24h in the environment. Finally the above array wash was placed at 80^oAnd C, drying in an oven for 10-24h to obtain the self-supporting NVO nanowire sodium ion battery array material. The mass ratio of ammonium metavanadate to NaOH is 0.01: 1-10. Wherein the concentration of the dilute hydrochloric acid is 1-3 mol L^-1And adjusting the pH value of the solution to 2-4.

The self-supporting NVO nanowire array sodium ion negative electrode material and the preparation method thereof have the following characteristics: the NVO synthesized by the method does not need high-temperature sintering, and has low preparation cost, simple experimental process and easy operation; the NVO nanowire array material obtained in the invention is quite tightly contacted with the substrate, and almost no active substance falls off when the NVO nanowire array material is placed in distilled water for long-time ultrasonic treatment;

the prepared NVO array has the width of 0.045-0.25 mu m and the length of 1-3 mu m;

the mass of the prepared NVO array material active substance is 2-4 mg cm^-2。

In a preferred embodiment, the obtained NVO array material has a specific chemical formula of Na_0.56V₂O₅。

Drawings

FIG. 1 is an XRD pattern of a sample prepared in example 1;

FIG. 2 is an SEM photograph of a sample prepared in example 1;

FIG. 3 shows the sweep rate of 0.5 mV s for the sample prepared in example 1^-1Corresponding cyclic voltammetry curve under the condition;

FIG. 4 is a graph (a) of the first three times of charge and discharge performance and a graph (b) of the cycle performance of the sample prepared in example 1 corresponding to a voltage window of 0.01-3V;

FIG. 5 is a graph (a) and (b) of the first three times of charge and discharge performance of the sample prepared in example 2 in a voltage window of 1.3-4V

A cycle performance map (b);

FIG. 6 is a graph showing the charging and discharging performance of the sample prepared in example 3 in a voltage window of 1.3-4V.

Detailed Description

Example 1

0.01 mol of ammonium metavanadate powder was placed in a beaker and 70 mL of deionized water was added and placed in 75^oC continuously stirring in water bath for 30 min, and dropwise adding 2 mol L solution^-1The hydrochloric acid solution adjusted the pH to 4.0. The above solution was transferred to a 100 mL hydrothermal reaction kettle and nickel foam (3X 7 cm) was added²) At 180^oC, carrying out hydrothermal reaction for 24 hours, wherein the foamed nickel is inclined at an angle of 60 DEGAgainst a hydrothermal kettle and then further in air 500^oAnnealing for 1 h to obtain V₂O₅And (4) nanowire arrays. Will V₂O₅The nanowire array is placed in 2M NaOH solution at 180 DEG^oC hydrothermal reaction for 12h, and then placing the mixture at 80^oAnd C, drying in an oven to obtain the NVO nanowire array. Fig. 1 is an XRD pattern of the prepared NVO nanowire array. It can be seen that characteristic peaks of NVO appear at 19.6 °, 30.0 °, 33.6 °, 33.8 °, 59.4 °, 70.5 °, and 73.2 °, respectively, in addition to characteristic peaks of Ni and NiO, and the XRD pattern thereof is similar to that of Na_0.56V₂O₅Is more consistent. As shown in fig. 2, SEM characterization of the NVO array can show that the prepared NVO array has a nanowire-like morphology, and the prepared material can be further determined to be Na by EDS surface scanning_0.56V₂O₅And are uniformly distributed on the Ni net. NVO was assembled into sodium ion half cells and tested for electrochemical performance. As shown in fig. 4a, the charging and discharging voltage plateau is consistent with the cyclic voltammogram (fig. 3). The sodium ion battery can be used as a negative electrode material to be assembled into a sodium ion half-cell, and a charge-discharge test is carried out under the condition that the voltage window of 0.33C multiplying power is 0.01-3V, so that the first discharge capacity reaches 620.4 mAh g^-1Capacity attenuation to 200 mAh g in the first 10 cycles^-1The back volume remains stable. Still has 146.2 mAh g after 100 cycles^-1The specific capacity (figure 4b) of the electrochemical cell is about 98 percent of coulombic efficiency, and the electrochemical performance is better.

Example 2

0.01 mol of ammonium metavanadate powder was placed in a beaker and 70 mL of deionized water was added and placed in 75^oC continuously stirring in water bath for 30 min, and dropwise adding 2 mol L solution^-1The hydrochloric acid solution adjusted the pH to 4.0. The above solution was transferred to a 100 mL hydrothermal reaction kettle and nickel foam (3X 7 cm) was added²) At 180^oC, carrying out hydrothermal reaction for 24h, wherein the foamed nickel is leaned in the hydrothermal kettle at an angle of 60 degrees, and then further 500 hours in air^oAnnealing for 1 h to obtain V₂O₅And (4) nanowire arrays. Will V₂O₅The nanowire array is placed in 2M NaOH solution at 180 DEG^oC hydrothermal reaction12h, then it is placed at 80^oAnd C, drying in an oven to obtain the NVO nanowire array. The sodium ion semi-cell is assembled into a sodium ion semi-cell, and a charge-discharge test is carried out under the condition that the 0.75C multiplying power voltage window is 1.3-4V, so that a charge-discharge voltage platform is obvious (figure 5a), and the fact that high-concentration NaOH is beneficial to successfully preparing the NVO anode material is shown. The first discharge capacity reaches 90.2 mAh g^-1After 50 cycles, the capacity is attenuated to 10.4 mAh g^-1(FIG. 5b), it is shown that the electrochemical performance of the NVO cathode material has a larger promotion space.

Example 3

0.01 mol of ammonium metavanadate powder was placed in a beaker and 70 mL of deionized water was added and placed in 75^oC continuously stirring in water bath for 30 min, and dropwise adding 2 mol L solution^-1The hydrochloric acid solution adjusted the pH to 4.0. The above solution was transferred to a 100 mL hydrothermal reaction kettle and nickel foam (3X 7 cm) was added²) At 180^oC, carrying out hydrothermal reaction for 24h, wherein the foamed nickel is leaned in the hydrothermal kettle at an angle of 60 degrees, and then further 500 hours in air^oAnnealing for 1 h to obtain V₂O₅And (4) nanowire arrays. Will V₂O₅The nanowire array was placed in 0.5M NaOH solution at 180 deg.C^oC hydrothermal reaction for 12h, and then placing the mixture at 80^oAnd C, drying in an oven to obtain the NVO nanowire array. The sodium ion semi-cell is assembled into a sodium ion semi-cell, and a charge and discharge test is carried out under the condition that the 0.5C multiplying power voltage window is 1.3-4V, so that an obvious NVO charge and discharge voltage platform (shown in figure 6) is not seen, and the NVO anode material cannot be successfully prepared by sodium intercalation under the condition of low-concentration NaOH.

Claims (1)

1. Self-supporting Na _x V₂O₅The nanowire sodium ion battery array material is characterized in that: active substance Na _x V₂O₅Has the chemical formula of Na_0.56V₂O₅The Na is_0.56V₂O₅The length of a single nanowire of the nanowire ion battery array is 1-3 mu m, the width of the nanowire is 0.045-0.25 mu m, and Na_0.56V₂O₅Mass of active material of nanowire materialIs 2-4 mg cm^-2The preparation method comprises the following steps:

0.01 mol of ammonium metavanadate powder was placed in a beaker and 70 mL of deionized water was added and placed in 75^oC continuously stirring in water bath for 30 min, and dropwise adding 2 mol L solution^-1Adjusting the pH value to 4.0 by hydrochloric acid solution; the solution is transferred into a 100 mL hydrothermal reaction kettle and added with 3 multiplied by 7 cm²At 180 of nickel foam^oC, carrying out hydrothermal reaction for 24h, wherein the foamed nickel is leaned in the hydrothermal kettle at an angle of 60 degrees, and then further 500 hours in air^oAnnealing for 1 h to obtain V₂O₅Array of nanowires, mixing V₂O₅The nanowire array is placed in 2M NaOH solution at 180 DEG^oC hydrothermal reaction for 12h, and then placing the mixture at 80^oDrying in a C drying oven to obtain Na_0.56V₂O₅A nanowire.

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