Carbon coated sodium manganese pyrophosphate@graphene oxide composite material with sandwich structure, as well as preparation method and application thereof

Abstract

The invention discloses a carbon coated sodium manganese pyrophosphate@graphene oxide composite material with a sandwich structure, as well as a preparation method and application thereof. The composite material is formed by stacking graphene oxide sheets, wherein carbon coated sodium manganese pyrophosphate particles are uniformly distributed on the surfaces of the graphene oxide sheets. The preparation method comprises the following steps: adding the graphene oxide into an aqueous solution in which a phosphorus source, a sodium source, a manganese source and a complexing agent are dissolved, and performing ultrasonic treatment, liquid nitrogen freezing and freeze drying sequentially to obtain a precursor; putting the precursor under protective atmosphere and performing heat treatment to obtain the carbon coated sodium manganese pyrophosphate@graphene oxide composite material with the sandwich structure. The carbon coated sodium manganese pyrophosphate@graphene oxide composite material serving as a sodium ion battery positive electrode material has excellent electrochemical property; the 'Na-Mn-P-O' system resource is rich, and the cost is low; the preparation method is simple to operate, and the commercial application prospect is wide.

Description

technical field

[0001] The invention relates to a positive electrode material of a sodium ion battery, in particular to a composite positive electrode material of carbon-coated sodium manganese pyrophosphate and graphene oxide with a sandwich structure and a preparation method thereof, and the application of the composite material as a sodium ion battery, belonging to Na-ion battery field. Background technique

[0002] Due to the advantages of high energy density, high stability, and long life, lithium-ion batteries have rapidly occupied the market of portable electronic products (notebook computers, smart mobile equipment, tablet computers, etc.), and continue to penetrate into the field of electric vehicles. However, the reserves of lithium resources in the earth's crust are low and the geographical distribution is uneven, which makes lithium prices continue to rise in the process of large-scale promotion and application of lithium-ion batteries, resulting in high prices f...

Examples

Embodiment 1

[0042] First, take 0.005mol of manganese acetate tetrahydrate, 0.01mol of ammonium dihydrogen phosphate, 0.005mol of anhydrous sodium carbonate and 2.88g of anhydrous citric acid (3:1 molar ratio to manganese), dissolve them in 50mL of deionized water, and stir thoroughly. A clear solution was obtained. Then 0.067g (5% of the mass of sodium manganese pyrophosphate) graphene oxide was added to the solution, and after ultrasonic treatment for 30min, the solution was placed in a water bath at 80°C for 6h. The solution was frozen in liquid nitrogen, and then placed in a freeze dryer to lyophilize. The obtained precursor was placed in an inert atmosphere tube furnace and sintered at 600°C for 9 hours, and the obtained solid product was a carbon-coated sodium manganese pyrophosphate@graphene oxide composite positive electrode material with a sandwich structure. The X-ray diffraction pattern (XRD) of the prepared "sandwich" structure carbon-coated sodium manganese pyrophosphate@grap...

Embodiment 2

[0045] First, take 0.005 mol of manganese acetate tetrahydrate, 0.01 mol of ammonium dihydrogen phosphate, 0.005 mol of anhydrous sodium carbonate and 3.84 g of anhydrous citric acid (4:1 molar ratio to manganese), dissolve them in 50 mL of deionized water, and stir thoroughly. A clear solution was obtained. Then 0.067g (5% of the mass of sodium manganese pyrophosphate) graphene oxide was added to the solution, and after ultrasonic treatment for 30 minutes, it was placed in a water bath at 80° C. for 6 hours, then frozen in liquid nitrogen, and then placed in a freeze dryer to lyophilize. The obtained precursor was placed in an inert atmosphere tube furnace and sintered at 600°C for 9 hours, and the obtained solid product was a carbon-coated sodium manganese pyrophosphate@graphene oxide composite positive electrode material with a sandwich structure. Sodium manganese pyrophosphate particles have a particle size of 300-500nm and a specific surface area of ​​110m 2 g- 1 .

[...

Embodiment 3

[0048] First, take 0.005mol of manganese acetate tetrahydrate, 0.01mol of ammonium dihydrogen phosphate, 0.005mol of anhydrous sodium carbonate and 2.88g of anhydrous citric acid (3:1 molar ratio to manganese), dissolve them in 50mL of deionized water, and stir thoroughly. A clear solution was obtained. Then 0.134g (8% of the mass of sodium manganese pyrophosphate) graphene oxide was added to the solution, and after ultrasonic treatment for 30 minutes, it was placed in a water bath at 80° C. for 6 hours, frozen in liquid nitrogen, and then placed in a freeze dryer to lyophilize. The obtained precursor was placed in an inert atmosphere tube furnace and sintered at 600°C for 9 hours, and the obtained solid product was a carbon-coated sodium manganese pyrophosphate@graphene oxide composite positive electrode material with a sandwich structure.

[0049] The sodium ion battery composite positive electrode material prepared in this example and the sodium sheet were assembled into a ...

technical field

[0001] The invention relates to a positive electrode material of a sodium ion battery, in particular to a composite positive electrode material of carbon-coated sodium manganese pyrophosphate and graphene oxide with a sandwich structure and a preparation method thereof, and the application of the composite material as a sodium ion battery, belonging to Na-ion battery field. Background technique

[0002] Due to the advantages of high energy density, high stability, and long life, lithium-ion batteries have rapidly occupied the market of portable electronic products (notebook computers, smart mobile equipment, tablet computers, etc.), and continue to penetrate into the field of electric vehicles. However, the reserves of lithium resources in the earth's crust are low and the geographical distribution is uneven, which makes lithium prices continue to rise in the process of large-scale promotion and application of lithium-ion batteries, resulting in high prices f...

Examples

Embodiment 1

[0042] First, take 0.005mol of manganese acetate tetrahydrate, 0.01mol of ammonium dihydrogen phosphate, 0.005mol of anhydrous sodium carbonate and 2.88g of anhydrous citric acid (3:1 molar ratio to manganese), dissolve them in 50mL of deionized water, and stir thoroughly. A clear solution was obtained. Then 0.067g (5% of the mass of sodium manganese pyrophosphate) graphene oxide was added to the solution, and after ultrasonic treatment for 30min, the solution was placed in a water bath at 80°C for 6h. The solution was frozen in liquid nitrogen, and then placed in a freeze dryer to lyophilize. The obtained precursor was placed in an inert atmosphere tube furnace and sintered at 600°C for 9 hours, and the obtained solid product was a carbon-coated sodium manganese pyrophosphate@graphene oxide composite positive electrode material with a sandwich structure. The X-ray diffraction pattern (XRD) of the prepared "sandwich" structure carbon-coated sodium manganese pyrophosphate@grap...

Embodiment 2

[0045] First, take 0.005 mol of manganese acetate tetrahydrate, 0.01 mol of ammonium dihydrogen phosphate, 0.005 mol of anhydrous sodium carbonate and 3.84 g of anhydrous citric acid (4:1 molar ratio to manganese), dissolve them in 50 mL of deionized water, and stir thoroughly. A clear solution was obtained. Then 0.067g (5% of the mass of sodium manganese pyrophosphate) graphene oxide was added to the solution, and after ultrasonic treatment for 30 minutes, it was placed in a water bath at 80° C. for 6 hours, then frozen in liquid nitrogen, and then placed in a freeze dryer to lyophilize. The obtained precursor was placed in an inert atmosphere tube furnace and sintered at 600°C for 9 hours, and the obtained solid product was a carbon-coated sodium manganese pyrophosphate@graphene oxide composite positive electrode material with a sandwich structure. Sodium manganese pyrophosphate particles have a particle size of 300-500nm and a specific surface area of ​​110m 2 g- 1 .

[...

Embodiment 3

[0048] First, take 0.005mol of manganese acetate tetrahydrate, 0.01mol of ammonium dihydrogen phosphate, 0.005mol of anhydrous sodium carbonate and 2.88g of anhydrous citric acid (3:1 molar ratio to manganese), dissolve them in 50mL of deionized water, and stir thoroughly. A clear solution was obtained. Then 0.134g (8% of the mass of sodium manganese pyrophosphate) graphene oxide was added to the solution, and after ultrasonic treatment for 30 minutes, it was placed in a water bath at 80° C. for 6 hours, frozen in liquid nitrogen, and then placed in a freeze dryer to lyophilize. The obtained precursor was placed in an inert atmosphere tube furnace and sintered at 600°C for 9 hours, and the obtained solid product was a carbon-coated sodium manganese pyrophosphate@graphene oxide composite positive electrode material with a sandwich structure.

[0049] The sodium ion battery composite positive electrode material prepared in this example and the sodium sheet were assembled into a ...

Images