LU500866B1

LU500866B1 - CATHODE MATERIAL Mo-VS4/N-GNTS OF MAGNESIUM-ION BATTERY AND USE THEREOF

Info

Publication number: LU500866B1
Application number: LU500866A
Authority: LU
Inventors: Xin Dai; Alan Meng; Shiqi Ding; Guanying Song; Zhenjiang Li
Original assignee: Qingdao Univ Of Science And Technology
Priority date: 2020-11-27
Filing date: 2021-11-16
Publication date: 2022-05-17
Also published as: NL2029729A; NL2029729B1; CN112490438A; CN112490438B; ZA202108878B

Abstract

The present disclosure discloses a cathode material Mo-doped VS4/nitrogen-doped graphene tubes (Mo-VS4/N-GNTs) of a magnesium-ion battery and use thereof, and belongs to the technical field of battery materials. Ammonium metavanadate and ammonium molybdate are mixed at an appropriate ratio, mixed with an excess amount of a thioacetamide solution and then transferred into an autoclave along with N-GNTs prepared by using a vapor deposition method for a thermal reaction at 200°C for 4 hours; a resulting product is separately rinsed with deionized water and absolute ethanol for 3 times and then dried to obtain the cathode material Mo-VS4/N-GNTs of a magnesium-ion battery. In the present disclosure, a Mo-doped VS4 nanosheet arrays grow in situ on an N-GNTs skeleton material by using a one-step hydrothermal method. Due to introduction of the N-GNT, the electrical conductivity of a composite material is improved, active materials uniformly grow on surfaces of the N-GNT, agglomeration of the active materials is prevented, and convenience is provided for tightly bonding the active materials to the conductive skeleton material, thereby improving the electrochemical performance of the magnesium-ion battery.The magnesium-ion battery assembled from the Mo-VS4/N-GNT has good cycle stability and rate performance, and thus having a broad application prospect.

Description

CATHODE MATERIAL Mo-VS4/N-GNTS OF MAGNESIUM-ION BATTERY AND USE 999906

THEREOF TECHNICAL FIELD

[01] The present disclosure relates to the technical field of battery materials, and specifically relates to a cathode material Mo-doped VS4/nitrogen-doped graphene tubes (Mo-VS4/N-GNTs) of a magnesium-ion battery and use thereof.

BACKGROUND ART

[02] With continuous increase of human demands for energy, traditional energy can no longer meet the human demands. Renewable energy is considered to be an effective way to solve energy crisis. However, large-scale development and utilization of new energy are limited due to unstable power output. As an energy storage technology with high cost performance, high energy efficiency and long service life, batteries can store the renewable energy and achieve stable output utilization, so that the batteries become widely used. However, since lithium-ion batteries widely used at present have faced severe safety problems and limited resources challenges, more researches are conducted on new battery technologies such as potassium-ion batteries, magnesium-ion batteries and sodium-ion batteries. In alkali metal ion batteries, due to high safety and low cost advantages, the magnesium-ion batteries are considered to be most suitable substitutes for the commercial lithium-ion batteries. However, due to a high polarization effect, the diffusion kinetics of divalent magnesium ions in cathode materials is lower than that of monovalent ion. Therefore, the key to improving the electrochemical storage capacity of magnesium ions is to explore and obtain a suitable cathode material.

[03] In existing cathode materials of the magnesium-ion batteries, VS4, having a one-dimensional chain-like crystal structure and a large chain spacing (0.56 nm), can be used as a potential cathode material of the magnesium-ion batteries. However, due to problems such as low electrical conductivity and serious polarization, the electrochemical performance such as rate performance and cycle stability of unmodified VS; are still unsatisfactory. A carbon material has good physical and chemical properties, and problems such as low inherent electrical conductivity of the VS4 are expected to be solved by combining the VS4 with the carbon materials. In recent years, as a new type of carbon family configuration materials, nitrogen-doped graphene tubes (N-GNTs) has one-dimensional tubular nanostructure. At the same time, introduced element nitrogen can replace a sp? hybridized carbon atom in the graphene tube to change electronic arrangement, so that a large number of defects are generated. These defects are favorable for in situ growth of active materials on surfaces of the nitrogen-doped 1 graphene tubes, so that the active materials can be tightly bonded to the nitrogen-doped graphene 209866 tubes (reference document: Co(@Co:04 encapsulated in carbon nanotube-grafted nitrogen-doped carbon polyhedra as an advanced bifunctional oxygen electrode, Arshad Aijaz et al. Angew. Chem. Int. Edit, 2016, 5, 4087-4091). In addition, the N-GNTs introduced as skeleton are also favorable for preventing agglomeration and separation of the active materials in a circulation process and then maintaining structural stability. Inspired by the advantages above, a cathode material with high electrochemical performance of a magnesium-ion battery is expected to be obtained by combining a VS4 nanosheet arrays with N-GNTs conductive skeleton materials.

[04] Moreover, doping with a specific foreign element is also one of effective ways to improve the electrochemical performance of VS4. An electronic structure of a main material is adjusted by doping Mo element, thereby improving the electrical conductivity. At the same time, when a host material is doped with an ion, lattice parameters, grain sizes and mechanical properties may be changed, so that convenience is provided for improving the diffusion kinetics of Mg”*, thereby improving the cycle life and rate performance of a magnesium-ion battery (reference document: Cuprous self-doping regulated mesoporous CuS nanotube cathode materials for rechargeable magnesium batteries, Changliang Du et al. ACS Appl. Mater. Inter. 2020, 12, 35035-35042). In addition, more sulfur vacancies can be induced, the electronic conductivity is improved, and ion/electron transport is facilitated due to element doping. According to a synergistic effect of N-GNTs and Mo doping, the VS4 is modified by introducing N-GNTs and Mo doping at the same time to obtain a cathode material with high electrochemical performance of a magnesium-ion battery. At present, there are few reports on Mo-doped VS4 growing in situ on the nitrogen-doped graphene tubes to serve as a cathode material and use of the Mo-doped VS4 in the magnesium-ion batteries.

[05] In the present disclosure, Mo-doped VS4 composited with nitrogen-doped graphene tubes (Mo-VS4/N-GNTs) is prepared by a one-step hydrothermal method to serve as a cathode material of a magnesium-ion battery, and the electrochemical performance of the Mo-VS4/N-GNTs applied in the magnesium-ion battery is studied. According to electrochemical performance test results, it shows that based on the synergistic effect of introduction of the N-GNTs and Mo doping, the cycle performance and rate performance of the VS; are improved. A specific capacity of the Mo-VS4/N-GNTS is maintained to be about 76.6 mAh g" after circulation for 1,200 cycles at a current density of 300 mA g!, and a capacity retention ratio reaches 75%. In addition, when the current density is increased from 20 mA g! to 500 mA gl, the specific capacity of the electrode material is changed from 151.7 mAh g! to 77.1 mAh g!; and when the current density is changed back to 20 mA g'!, the specific capacity is gradually recovered to 145 mAh gl, and good rate performance is achieved. The present disclosure provides an innovative 2 and feasible way to modify an electrode material with high electrochemical performance of an 509666 ion battery.

SUMMARY

[06] An objective of the present disclosure is to provide a cathode material of a magnesium-ion battery, and particularly provide use of a cathode material Mo-doped VSy/nitrogen-doped graphene tubes (Mo-VS4/N-GNTs) of a magnesium-ion battery. A Mo-doped VS4 nanosheet array grows in situ on three-dimensional N-GNTs conductive skeleton and has better cycling stability and high rate performance.

[07] In order to achieve the objective above, the cathode material Mo-VS4/N-GNTs of a magnesium-ion battery provided in the present disclosure is prepared in the following process:

[08] 1. weighing melamine and silicon powder at a mass ratio of 9:1, conducting full grinding, placing a resulting mixture and carbon paper with a catalyst added dropwise into a vertical vacuum atmosphere furnace for calcination, and then conducting the furnace cooling to room temperature to obtain N-GNTs uniformly growing on the surface of the carbon paper;

[09] 2. weighing ammonium metavanadate and ammonium molybdate tetrahydrate at a ratio of 1160:1, dissolving the two drugs in deionized water to prepare a solution with a concentration of 0.167 M, and then conducting magnetic stirring at a constant temperature of 60°C for 30 minutes until the drugs are completely dissolved to obtain a solution À;

[10] 3. weighing an excess amount of thioacetamide, dissolving the thioacetamide in ethylene glycol with a same volume as an aqueous solution, and then conducting magnetic stirring at room temperature for 30 minutes until the thioacetamide is completely dissolved to obtain a solution B;

[11] 4. mixing the solution B and the solution A, and then conducting magnetic stirring at a constant temperature of 60°C for 30 minutes until the two solutions are completely mixed, to obtain a mixed solution;

[12] 5. transferring the mixed solution and the carbon paper with growth of the N-GNTs into a 100 ml autoclave, conducting heating to 200°C and reacting for 4 hours, and then conducting furnace cooling to room temperature after the reaction is completed; and

[13] ©. taking out reacted carbon paper, separately rinsing the carbon paper with deionized water and absolute ethanol for 3 times, and then placing a resulting product into a vacuum drying oven for drying treatment at a temperature of 60°C for 12 hours to obtain the cathode material Mo-VS4/N-GNTs of a magnesium-ion battery.

[14] The present disclosure also provides use of the Mo-VS4/N-GNTs as a cathode material in a magnesium-ion battery, and the Mo-VS4/N-GNTs, metallic magnesium as an anode, a glass 3 fiber as a separator and advanced polymer chromatography-tetrahydrofuran (APC-THF) as an 500806 electrolyte are assembled into a button battery. After the assembled battery is subjected to standing for 24 hours, an electrochemical performance test is conducted by using a CT2001A battery program-controlled tester with a test voltage window of 0.2-2.1 V and a current density of 20-500 mA g.

[15] The cathode material Mo-VS4/N-GNTs of a magnesium-ion battery provided in the present disclosure has the following advantages:

[16] 1. according to the cathode material Mo-VS4/N-GNTs of a magnesium-ion battery synthesized in the present disclosure, the Mo-doped VS4 nanosheet arrays in situ grow on the three-dimensional N-GNTs conductive skeleton, so that convenience is provided for improving the electrical conductivity of a composite material, making active materials tightly bonded to a conductive skeleton material, reducing interface resistance, and convenience is provided for improving the reaction kinetics;

[17] 2. according to the cathode material Mo-VS4/N-GNTs of a magnesium-ion battery prepared in the present disclosure, the active materials are uniformly dispersed on the N-GNTs due to introduction of the N-GNTs conductive skeleton material, so that infiltration of the electrolyte into the electrode material is facilitated, more active sites are exposed, and a specific capacity of the magnesium-ion battery is increased; and

[18] 3. the cathode material Mo-VS4/N-GNTs of a magnesium-ion battery prepared in the present disclosure has excellent electrochemical performance: a long cycle life of 1,200 cycles at a current density of 300 mA g! is achieved, the specific capacity is maintained to be about 76.6 mAh g'!, and a capacity retention ratio reaches 75%. In addition, when the current density is increased from 20 mA g'' to 500 mA gl, the specific capacity of the electrode material is changed from 151.7 mAh g“ to 77.1 mAh g'!; and when the current density is changed back to mA g'!, the specific capacity is recovered to 145 mAh g'!, and good rate performance is achieved.

[19] The concept, morphology, structure and technical effects of the present disclosure are further described below in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[20] The accompanying drawings are provided for further understanding of the present disclosure, and constitute part of the specification. The accompanying drawings and specific embodiments of the present disclosure are intended to explain the present disclosure, rather than to limit the present disclosure. In the drawings:

[21] FIG. 1 is an SEM image of a cathode material Mo-doped VS4/nitrogen-doped graphene 4 tubes (Mo-VS4/N-GNTs) of a magnesium-ion battery obtained in Example 1; 7500866

[22] FIG. 2 is an XRD pattern of the cathode material Mo-VS4/N-GNTs of a magnesium-ion battery obtained in Example 1;

[23] FIG. 3 is a Raman spectrum of the cathode material Mo-VS4/N-GNTs of a magnesium-ion battery obtained in Example 1;

[24] FIG. 4 is a high-resolution XPS spectrum of Mo of the cathode material Mo-VS4/N-GNTs of a magnesium-ion battery obtained in Example 1;

[25] FIG. 5 is a high-resolution XPS spectrum of S of the cathode material Mo-VS4/N-GNTs of a magnesium-ion battery obtained in Example 1;

[26] FIG. 6 shows a rate performance curve of the cathode material Mo-VS4/N-GNTs of a magnesium-ion battery obtained in Example 1; and

[27] FIG. 7 shows a cycle performance curve of the cathode material Mo-VS4/N-GNTs of a magnesium-ion battery obtained in Example 1.

DETAILED DESCRIPTION OF THE EMBODIMENTS

[28] The present disclosure is further described in detail below in conjunction with specific examples, but these examples do not limit the scope of the present disclosure in any way.

[29] Example

[30] Use of a cathode material Mo-doped VSs/nitrogen-doped graphene tubes (Mo-VS4/N-GNTs) of a magnesium-ion battery

[31] 12.6 g of melamine and 1.4 g of silicon powder were weighed, fully ground and then placed into a vertical vacuum atmosphere furnace along with carbon paper with a catalyst nickel nitrate added dropwise, a reaction temperature was 1,250°C, the heat preservation time was 30 minutes, and then furnace cooling was conducted to room temperature to obtain carbon paper with uniform growth of N-GNTs; 0.5814 g of ammonium metavanadate and 0.0265 g of ammonium molybdate tetrahydrate were weighed, dissolved in 30 ml of deionized water and then subjected to magnetic stirring at a constant temperature of 60°C for 30 minutes until the ammonium metavanadate and the ammonium molybdate tetrahydrate were completely dissolved to obtain a solution A; at the same time, an excess amount of thioacetamide was weighed, dissolved in 30 ml of ethylene glycol and then subjected to magnetic stirring at room temperature for 30 minutes until the thioacetamide was completely dissolved to obtain a solution B; and the solution B was poured into the solution A for mixing, and the two solutions were subjected to magnetic stirring at a constant temperature of 60°C for 30 minutes until the two solutions were completely mixed to obtain a mixed solution. The mixed solution and the carbon paper with uniform growth of the N-GNTs were transferred into a 100 ml autoclave for a hydrothermal reaction at a temperature of 200°C for 4 hours, and then autoclave cooling was conducted to 200866 room temperature after the reaction was completed, and the carbon paper was taken out, separately rinsed with deionized water and absolute ethanol for 3 times and then placed into a vacuum drying oven for drying at a temperature of 60°C for 12 hours to obtain a cathode material Mo-VS4/N-GNTS of a magnesium-ion battery.

[32] After the hydrothermal reaction, a Mo-doped VS4 nanosheet arrays uniformly grew in situ on the N-GNTs, which was shown in an SEM image (FIG. 1). According to XRD result (FIG. 2), characteristic peaks of VS4 and the N-GNTs were observed, and diffraction peaks of the VS4 were shifted to a lower angle relative to a standard pattern, proving that Mo was doped into a crystal lattice of the VS4. À high-resolution XPS spectrum of Mo (FIG. 3) showed that a valence state of Mo was +4, so that Mo was doped into the crystal lattice of the VS4 in a Mo*" state. A high-resolution spectrum of S (FIG. 4) showed that S had both -1 and -2 valences, indicating that more sulfur vacancies were formed after Mo doping, and an S-C bond proved that the Mo-doped VS4 was tightly connected to the N-GNTs through bonding. According to Raman result (FIG. 5), A1 and Bı referred to a stretching mode and a bending mode of a V-S bond, respectively, and a C-S bond could be observed, further indicating that the Mo-doped VS4 was tightly combined with the N-GNTs through bonding. Moreover, an intensity of a D-band of the N-GNTs was higher than that of a G-band, indicating that the N-GNTs had defects.

[33] The prepared Mo-VS4/N-GNTs as a cathode material of a magnesium-ion battery, a polished magnesium foil as an anode material of the magnesium-ion battery, a glass fiber filter membrane as a separator and 0.4 M advanced polymer chromatography-tetrahydrofuran (APC-THF) as an electrolyte were assembled into a button battery in a glove box under an argon atmosphere. After the assembled magnesium-ion battery was subjected to standing for 24 hours, an electrochemical performance test was conducted by using a CT2001A battery program-controlled tester with a test voltage window of 0.2-2.1 V and a current density of 20-500 mA gt.

[34] The rate performance of the obtained cathode material Mo-VS4/N-GNTs of the magnesium-ion battery was shown in FIG. 6. When the current density was increased from 20 mA g! to 500 mA g”!, a specific capacity was changed from 151.7 mAh g" to 77.1 mAh g!; and when the current density was changed back to 20 mA g'!, the specific capacity was gradually recovered to 145 mAh g!, and good rate performance was achieved. The cycling performance was shown in FIG. 7. The capacity was still maintained to be about 75% of an initial capacity value after circulation for 1,200 cycles at a current density of 300mA g!, and good cycle stability is achieved.

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Claims

WHAT IS CLAIMED IS: HU500868

1. A cathode material Mo-doped VS4/nitrogen-doped graphene tubes (Mo-VS4/N-GNTs) of a magnesium-ion battery and use thereof, wherein the Mo-VS4/N-GNTs is prepared in the following process: weighing melamine and silicon powder at a mass ratio of 9:1, conducting full grinding, placing a resulting mixture and carbon paper with a catalyst added dropwise into a vertical vacuum atmosphere furnace for calcination, and then conducting cooling to room temperature to obtain N-GNTs uniformly growing on the surface of the carbon paper; weighing ammonium metavanadate and ammonium molybdate tetrahydrate at a ratio of 1,160:1, and preparing an aqueous solution with a concentration of 0.167 M at a constant temperature of 60°C; weighing excess amount of thioacetamide, and preparing an ethylene glycol solution with a same volume as the aqueous solution; fully mixing the two solutions to obtain a mixed solution, transferring the mixed solution and the carbon paper with growth of the N-GNTs into an autoclave for a hydrothermal reaction at a temperature of 200°C for 4 hours, collecting reacted carbon paper after the reaction is completed, separately rinsing the carbon paper with deionized water and absolute ethanol for 3 times, and then conducting vacuum drying to obtain the cathode material Mo-VS4/N-GNTs of a magnesium-ion battery; and the obtained cathode material Mo-VS4/N-GNTs of a magnesium-ion battery is assembled into a button magnesium-ion battery, and an electrochemical performance test is conducted with a voltage window of 0.2-2.1 V and a current density of 20-500 mA g'!.

2. The cathode material Mo-VS4/N-GNTs of a magnesium-ion battery and use thereof according to claim 1, wherein Mo-doped VS4 nanosheet arrays uniformly grow in situ on an N-GNTs skeleton material in a three-dimensional structure.

3. The cathode material Mo-VS4/N-GNTs of a magnesium-ion battery and use thereof according to claim 1, wherein when the obtained cathode material is used as a cathode of the magnesium-ion battery, a specific capacity at a current density of 300 mA g"! is 76.6 mAh g!, a capacity retention rate reaches 75% after circulation for 1,200 cycles, and good rate performance is achieved.

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