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Oxygen-deficient metal oxide catalyst, in-situ preparation method thereof and lithium-sulfur battery

An in-situ preparation and oxygen deficiency technology, applied in the field of electrochemical energy, can solve the problems of weak adsorption capacity, loss of activity, and high preparation cost of polysulfides, and achieve excellent electrochemical performance, enhanced adsorption capacity, and improved conversion efficiency.

Pending Publication Date: 2022-05-10
SUZHOU INST OF NANO TECH & NANO BIONICS CHINESE ACEDEMY OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, three-dimensional graphene is easy to stack during the synthesis process, and graphene is a weakly polar substance, so its adsorption capacity for polar polysulfides is relatively weak
[0006] By simply adding metal oxides to the matrix of carbon materials, the above problems can be solved to a certain extent, but there are some problems: such as complex preparation process, uncontrollable product structure, high preparation cost; polar metal oxides such as TiO 2 , MnO 2 etc. has a strong adsorption capacity for polysulfides, but this kind of metal oxide is also a poor conductor of electrons, and it cannot be evenly distributed in the positive electrode material, and some metal oxides may also occur as the battery cycles. Agglomeration loses activity. In addition, these polar oxides are still lacking in the conversion of lithium polysulfide and the activation ability of lithium sulfide in the discharge product, and the active sites for catalytic conversion are far from enough.
Therefore, it is difficult to achieve the cycle performance at high rates, which hinders the industrialization process of lithium-sulfur batteries.

Method used

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  • Oxygen-deficient metal oxide catalyst, in-situ preparation method thereof and lithium-sulfur battery
  • Oxygen-deficient metal oxide catalyst, in-situ preparation method thereof and lithium-sulfur battery
  • Oxygen-deficient metal oxide catalyst, in-situ preparation method thereof and lithium-sulfur battery

Examples

Experimental program
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Effect test

Embodiment 1

[0060] Measure a certain amount of low-concentration graphene oxide solution (4mg / mL), according to the mass ratio of graphene oxide and carbon nanotubes is 2:1, weigh a certain mass of carbon nanotubes, add ultrapure water to dilute, ultrasonic 45min, Mixed solution A was obtained.

[0061] A mixed solution B was obtained by dispersing a niobium ion source (niobium chloride) and a nitrogen source (urea) in ethanol.

[0062] Add the mixed solution B dropwise to the ultrasonically good mixed solution A while stirring to obtain a precursor solution (wherein, the concentration of graphene oxide is 1.2mg / mL, and the total mass of dry matter in the precursor solution is 100% Calculated, the mass content of niobium ions is 5%, and the mass content of nitrogen in urea is 3%), after being fully stirred evenly, it is transferred to a reactor for hydrothermal reaction at 180° C. for 15 hours. When the hydrothermal product was cooled to room temperature, it was filtered and washed, free...

Embodiment 2

[0064] Measure a certain amount of low-concentration graphene oxide solution (5mg / mL), according to the mass ratio of graphene oxide and carbon nanotubes is 2:1, weigh a certain mass of carbon nanotubes, add ultrapure water to dilute, ultrasonic 45min, Mixed solution A was obtained.

[0065] Disperse the iron ion source (ferric chloride) and the nitrogen source (urea) in ethanol to obtain a mixed solution B.

[0066] Add the mixed solution B dropwise to the ultrasonically good mixed solution A while stirring to obtain a precursor solution (wherein, the concentration of graphene oxide is 1.5mg / mL, and the total mass of dry matter in the precursor solution is 100% Calculated, the mass content of iron ion is 7%, the mass content of nitrogen element in urea is 2%), after fully stirring evenly, transfer to the reaction kettle for hydrothermal reaction at 180°C for 15h. When the hydrothermal product was cooled to room temperature, it was filtered and washed, freeze-dried, and calci...

Embodiment 3

[0068] Measure a certain amount of low-concentration graphene oxide solution (4mg / mL), according to the mass ratio of graphene oxide and carbon nanotubes is 2:1, weigh a certain mass of carbon nanotubes, add ultrapure water to dilute, ultrasonic 45min, Mixed solution A was obtained.

[0069] A mixed solution B is obtained by dispersing a cobalt ion source (cobalt chloride) and a nitrogen source (urea) in ethanol.

[0070] Add the mixed solution B dropwise while stirring in the mixed solution A that has been sonicated to obtain a precursor solution (wherein, the concentration of graphene oxide is 1.3 mg / mL, and the total mass of dry matter in the precursor solution is 100% Calculated, the mass content of cobalt ions is 5%, and the mass content of nitrogen in urea is 1.5%), after being fully stirred, it is transferred to a reactor for hydrothermal reaction at 180° C. for 15 hours. When the hydrothermal product was cooled to room temperature, it was filtered and washed, freeze-d...

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Abstract

The invention discloses an oxygen-deficient metal oxide catalyst, an in-situ preparation method thereof and a lithium-sulfur battery. The method comprises the following steps: 1) preparing a precursor solution containing graphene oxide, a one-dimensional carbon material, a regulation and control ion source and a doping source; (2) carrying out hydrothermal reaction by adopting the precursor solution, and drying a hydrothermal product after the reaction is finished; and 3) carrying out primary calcination in the atmosphere of protective gas, and then carrying out secondary calcination in the atmosphere containing reducing gas to obtain the oxygen-deficient metal oxide catalyst. The method provided by the invention solves the problem of non-uniform dispersion of the metal oxide and the problem of partial agglomeration and inactivation of the metal oxide along with battery circulation, and is applied to the lithium-sulfur battery to realize efficient utilization, high energy density and long cycle life of the sulfur positive electrode.

Description

technical field [0001] The invention relates to the fields of electrochemical energy and materials, in particular to an oxygen-deficient metal oxide catalyst, its in-situ preparation method and a lithium-sulfur battery. Background technique [0002] Due to its high volume energy density and mass energy density, lithium-sulfur batteries are likely to be widely used in large energy storage devices and power grids in the future, such as electric vehicles. However, there are still some problems in lithium-sulfur batteries, such as the electronic ion insulation of the active material sulfur and lithium sulfide, the dissolution and diffusion of lithium polysulfide, and the volume expansion and contraction of the electrode during charging and discharging. [0003] At present, the actual energy density of the lithium-sulfur battery in the research stage is far lower than its theoretical energy density, and the cycle life of the battery is short, which is mainly attributed to the low...

Claims

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Application Information

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IPC IPC(8): H01M4/62H01M4/04H01M10/052
CPCH01M4/628H01M4/625H01M10/052H01M4/049H01M4/0471H01M2220/10H01M2004/028H01M2004/021
Inventor 蔺洪振程双王健
Owner SUZHOU INST OF NANO TECH & NANO BIONICS CHINESE ACEDEMY OF SCI