Nano-flaky porous transition metal oxide/carbon composite material and preparation method thereof

Abstract

The invention relates to a nano-sheet-shaped porous transition metal oxide / carbon composite material and a preparation method thereof, belonging to the field of electrochemical materials; the invention firstly dissolves the transition metal salt directly in ethylene glycol in an autoclave, 100~ Hydrothermal reaction at 180°C for 2~5h to generate transition metal coordination polymer precursor, which is washed and dried in a tube furnace in an inert atmosphere and decomposed at 450~600°C for 0.5~6h to generate a nanosheet containing nanosheets. porous transition metal oxide / carbon composite material; the material prepared by the method of the present invention has high electrical conductivity, high specific capacity, good cycle stability, excellent high-rate discharge performance and high energy density The preparation method of the invention is not only simple in process and low in preparation cost, but also the synthesized composite material can effectively improve its electrochemical performance, has higher primary reversible specific capacity and excellent cycle performance, and can be applied to secondary lithium ion batteries.

Description

technical field

[0001] The invention belongs to the field of electrochemical materials, and relates to a nanosheet porous transition metal oxide / carbon composite material and a preparation method thereof. Background technique

[0002] Energy storage is key to driving power system efficiency and profitability, and its demand is growing. Energy storage is becoming increasingly important in ground transportation in the quest for greater fuel efficiency. Among many energy storage technologies, lithium-ion batteries have developed rapidly due to their high efficiency and high specific energy. In recent years, with the commercial development of electric vehicles, hybrid vehicles, etc., lithium-ion batteries are facing increasing challenges. The development of lithium-ion batteries with high specific capacity, high power, long cycle life and low cost has become the main direction of its development. The electrode material is the core of the lithium-ion battery system, and the ne...

Examples

Embodiment 1

[0027] Example 1: Preparation of nanosheet-shaped porous trimanganese tetraoxide / carbon composite material and electrochemical performance test of a simulated battery assembled with lithium.

[0028] Put 6mmol of manganese acetate and 100ml of ethylene glycol into the autoclave, then vigorously stir and dissolve, heat at 170°C for 2h, and cool naturally to obtain the white sheet-like manganese-based complex Mn-EG, centrifuge, wash, vacuum dry. Put the obtained manganese-based complex Mn-EG into a tube furnace filled with nitrogen or argon, and thermally decompose it at 500°C for 2 hours to obtain a nanosheet-like structure of trimanganese tetraoxide / carbon composite material.

[0029] The resulting product was analyzed by X-ray diffraction as follows: figure 1 The shown diffraction pattern shows that the product is trimanganese tetraoxide without any impurity; the scanning electron micrograph is as follows figure 2 As shown, the nanodisc structure is assembled and stacked b...

Embodiment 2

[0032] Replace the manganese acetate in Example 1 with ferrous chloride. The difference is that 5 mmol of ferrous chloride and 100 ml of ethylene glycol are put into a high-pressure reactor and stirred vigorously to dissolve, heated at 100°C for 5 hours, cooled naturally, and decomposed The condition is to thermally decompose at 450° C. for 6 hours, and the other process steps are the same as in Example 1 to obtain the ferric oxide / carbon composite negative electrode material with a nano-flaky structure, and its scanning electron microscope picture is as follows: image 3 As shown in the figure, it can be seen that the material has a nano-disc structure, which is assembled and stacked by spherical particles, and the surface of these nano-spheres is uniformly coated with a layer of carbon film, and the particles are connected by a carbon network. Under the current density of 100 mA / g, the charge and discharge test results of the first three weeks are as follows: Figure 5 shown...

Embodiment 3

[0034]Manganese acetate in Example 1 was replaced by manganese acetate tetrahydrate. The difference was that 60 mmol of manganese acetate tetrahydrate and 100 ml of ethylene glycol were put into a high-pressure reactor and stirred vigorously to dissolve, heated at 180 ° C for 2 hours, cooled naturally, and decomposed conditions In order to thermally decompose at 600°C for 0.5h, the other process steps are the same as in Example 1 to obtain the nanosheet-shaped porous trimanganese tetraoxide / carbon composite material. At a current density of 100 mA / g, the charge and discharge test results for the first three weeks are as follows: Figure 6 shown. The charge and discharge capacities in the first three weeks were 1239 / 1863, 1245 / 1371, and 1252 / 1357 mAh / g, respectively.

technical field

[0001] The invention belongs to the field of electrochemical materials, and relates to a nanosheet porous transition metal oxide / carbon composite material and a preparation method thereof. Background technique

[0002] Energy storage is key to driving power system efficiency and profitability, and its demand is growing. Energy storage is becoming increasingly important in ground transportation in the quest for greater fuel efficiency. Among many energy storage technologies, lithium-ion batteries have developed rapidly due to their high efficiency and high specific energy. In recent years, with the commercial development of electric vehicles, hybrid vehicles, etc., lithium-ion batteries are facing increasing challenges. The development of lithium-ion batteries with high specific capacity, high power, long cycle life and low cost has become the main direction of its development. The electrode material is the core of the lithium-ion battery system, and the ne...

Examples

Embodiment 1

[0027] Example 1: Preparation of nanosheet-shaped porous trimanganese tetraoxide / carbon composite material and electrochemical performance test of a simulated battery assembled with lithium.

[0028] Put 6mmol of manganese acetate and 100ml of ethylene glycol into the autoclave, then vigorously stir and dissolve, heat at 170°C for 2h, and cool naturally to obtain the white sheet-like manganese-based complex Mn-EG, centrifuge, wash, vacuum dry. Put the obtained manganese-based complex Mn-EG into a tube furnace filled with nitrogen or argon, and thermally decompose it at 500°C for 2 hours to obtain a nanosheet-like structure of trimanganese tetraoxide / carbon composite material.

[0029] The resulting product was analyzed by X-ray diffraction as follows: figure 1 The shown diffraction pattern shows that the product is trimanganese tetraoxide without any impurity; the scanning electron micrograph is as follows figure 2 As shown, the nanodisc structure is assembled and stacked b...

Embodiment 2

[0032] Replace the manganese acetate in Example 1 with ferrous chloride. The difference is that 5 mmol of ferrous chloride and 100 ml of ethylene glycol are put into a high-pressure reactor and stirred vigorously to dissolve, heated at 100°C for 5 hours, cooled naturally, and decomposed The condition is to thermally decompose at 450° C. for 6 hours, and the other process steps are the same as in Example 1 to obtain the ferric oxide / carbon composite negative electrode material with a nano-flaky structure, and its scanning electron microscope picture is as follows: image 3 As shown in the figure, it can be seen that the material has a nano-disc structure, which is assembled and stacked by spherical particles, and the surface of these nano-spheres is uniformly coated with a layer of carbon film, and the particles are connected by a carbon network. Under the current density of 100 mA / g, the charge and discharge test results of the first three weeks are as follows: Figure 5 shown...

Embodiment 3

[0034]Manganese acetate in Example 1 was replaced by manganese acetate tetrahydrate. The difference was that 60 mmol of manganese acetate tetrahydrate and 100 ml of ethylene glycol were put into a high-pressure reactor and stirred vigorously to dissolve, heated at 180 ° C for 2 hours, cooled naturally, and decomposed conditions In order to thermally decompose at 600°C for 0.5h, the other process steps are the same as in Example 1 to obtain the nanosheet-shaped porous trimanganese tetraoxide / carbon composite material. At a current density of 100 mA / g, the charge and discharge test results for the first three weeks are as follows: Figure 6 shown. The charge and discharge capacities in the first three weeks were 1239 / 1863, 1245 / 1371, and 1252 / 1357 mAh / g, respectively.

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