Carbon layer-coated nano-manganese tetraoxide shell-core structure material and preparation method thereof

Abstract

The invention relates to a carbon layer coated nanometer Mn 3 o 4 Core-shell structural materials and their preparation methods and applications. Nano Mn of the present invention 3 o 4 The @C material was synthesized by impregnation and step-by-step calcination using plant cell tissue as a structure-directing agent. The synthesized material retained the biomorphology of the template, oxide nanoparticles and thin layers of biochar were formed during the step-by-step calcination, and the retention of biochar promoted the Mn 3 o 4 Nano-dispersion and grain growth, the obtained material is uniform without obvious agglomeration. During battery charging and discharging, biochar can effectively alleviate the structural collapse caused by lattice shrinkage during lithium ion deintercalation, and provide support and protection for volume changes. During cycling, the carbon layer can limit the aggregation and volume of nanoparticles. Swells, improving battery performance. When this material is used as a negative electrode material for lithium-ion batteries, it is stable at 840 mAhg after 250 cycles ‑1 High specific capacity, cycle coulombic efficiency is stable at 99%.

Description

technical field

[0001] The invention relates to the technical field of new materials, in particular to a carbon layer coated nanometer Mn 3 o 4 Core-shell structural materials and their preparation methods and applications. Background technique

[0002] Transition metal oxides have the characteristics of high theoretical specific capacity, abundant resources and relatively green environmental protection, so they have good development prospects in lithium-ion battery anode materials. In 2000, Poizot et al first proposed that transition metals can be combined with Li + A reversible reaction occurs between the Li + storage and release. Among many transition metal oxides, manganese oxides have attracted extensive attention due to their high theoretical specific capacity, abundant reserves, wide distribution, and non-toxicity, and are considered to be very promising substitutes for graphite. According to the current charge-discharge storage mechanism of transition metal oxid...

Examples

Embodiment 1

[0033] A kind of nano Mn 3 o 4 The synthetic method of @C material comprises the following steps:

[0034] (1) Wash the cabbage leaves with distilled water and soak them in EtOH solution (EtOH:H 2 O=1:1), and use hydrochloric acid to adjust the pH=2~4, pretreatment for two weeks to remove the organic matter and pigment in the cabbage leaves.

[0035] (2) Take out the pretreated cabbage leaves, wash them with distilled water and dry them, then soak them in 50% Mn(NO 3 ) 2The solution prepared with a concentration of 0.05 mol / L Mn(NO 3 ) 2 72 h in aqueous solution.

[0036] (3) Take out the soaked leaves, wash them with distilled water, and dry them at room temperature.

[0037] (4) Calcining the dried leaves, first in N 2 The temperature was raised to 600 °C under the atmosphere, and the heating rate was 10 °C min -1 , keep warm for 2 h, take it out and then raise the temperature to 700 °C in the air atmosphere, the heating rate is 10 °C·min -1 , and finally get the n...

Embodiment 2

[0045] (1) Wash the cabbage leaves with distilled water and soak them in EtOH solution (EtOH:H 2 O=1:1), and use hydrochloric acid to adjust the pH=2~4, pretreatment for two weeks to remove the organic matter and pigment in the cabbage leaves.

[0046] (2) Take out the pretreated cabbage leaves, wash them with distilled water and dry them, then soak them in 50% Mn(NO 3 ) 2 The concentration of solution preparation is 0.10mol / L Mn(NO 3 ) 2 72 h in aqueous solution.

[0047] (3) Take out the soaked leaves, wash them with distilled water, and dry them at room temperature.

[0048] (4) Calcining the dried leaves, first in N 2 The temperature was raised to 600 °C under the atmosphere, and the heating rate was 10 °C min -1 , keep warm for 2 h, take it out and then raise the temperature to 700 °C in the air atmosphere, the heating rate is 10 °C·min -1 , and finally get the nanometer Mn 3 o 4 @C material.

Embodiment 3

[0050] (1) Wash the cabbage leaves with distilled water and soak them in EtOH solution (EtOH:H 2 O=1:1), and use hydrochloric acid to adjust the pH=2~4, pretreatment for two weeks to remove the organic matter and pigment in the cabbage leaves.

[0051] (2) Take out the pretreated cabbage leaves, wash them with distilled water and dry them, then soak them in 50% Mn(NO 3 ) 2 The concentration of solution preparation is 0.15mol / L Mn(NO 3 ) 2 72 h in aqueous solution.

[0052] (3) Take out the soaked leaves, wash them with distilled water, and dry them at room temperature.

[0053] (4) Calcining the dried leaves, first in N 2 The temperature was raised to 600 °C under the atmosphere, and the heating rate was 10 °C min -1 , keep warm for 2 h, take it out and then raise the temperature to 700 °C in the air atmosphere, the heating rate is 10 °C·min -1 , and finally get the nanometer Mn 3 o 4 @C material.

technical field

[0001] The invention relates to the technical field of new materials, in particular to a carbon layer coated nanometer Mn 3 o 4 Core-shell structural materials and their preparation methods and applications. Background technique

[0002] Transition metal oxides have the characteristics of high theoretical specific capacity, abundant resources and relatively green environmental protection, so they have good development prospects in lithium-ion battery anode materials. In 2000, Poizot et al first proposed that transition metals can be combined with Li + A reversible reaction occurs between the Li + storage and release. Among many transition metal oxides, manganese oxides have attracted extensive attention due to their high theoretical specific capacity, abundant reserves, wide distribution, and non-toxicity, and are considered to be very promising substitutes for graphite. According to the current charge-discharge storage mechanism of transition metal oxid...

Examples

Embodiment 1

[0033] A kind of nano Mn 3 o 4 The synthetic method of @C material comprises the following steps:

[0034] (1) Wash the cabbage leaves with distilled water and soak them in EtOH solution (EtOH:H 2 O=1:1), and use hydrochloric acid to adjust the pH=2~4, pretreatment for two weeks to remove the organic matter and pigment in the cabbage leaves.

[0035] (2) Take out the pretreated cabbage leaves, wash them with distilled water and dry them, then soak them in 50% Mn(NO 3 ) 2The solution prepared with a concentration of 0.05 mol / L Mn(NO 3 ) 2 72 h in aqueous solution.

[0036] (3) Take out the soaked leaves, wash them with distilled water, and dry them at room temperature.

[0037] (4) Calcining the dried leaves, first in N 2 The temperature was raised to 600 °C under the atmosphere, and the heating rate was 10 °C min -1 , keep warm for 2 h, take it out and then raise the temperature to 700 °C in the air atmosphere, the heating rate is 10 °C·min -1 , and finally get the n...

Embodiment 2

[0045] (1) Wash the cabbage leaves with distilled water and soak them in EtOH solution (EtOH:H 2 O=1:1), and use hydrochloric acid to adjust the pH=2~4, pretreatment for two weeks to remove the organic matter and pigment in the cabbage leaves.

[0046] (2) Take out the pretreated cabbage leaves, wash them with distilled water and dry them, then soak them in 50% Mn(NO 3 ) 2 The concentration of solution preparation is 0.10mol / L Mn(NO 3 ) 2 72 h in aqueous solution.

[0047] (3) Take out the soaked leaves, wash them with distilled water, and dry them at room temperature.

[0048] (4) Calcining the dried leaves, first in N 2 The temperature was raised to 600 °C under the atmosphere, and the heating rate was 10 °C min -1 , keep warm for 2 h, take it out and then raise the temperature to 700 °C in the air atmosphere, the heating rate is 10 °C·min -1 , and finally get the nanometer Mn 3 o 4 @C material.

Embodiment 3

[0050] (1) Wash the cabbage leaves with distilled water and soak them in EtOH solution (EtOH:H 2 O=1:1), and use hydrochloric acid to adjust the pH=2~4, pretreatment for two weeks to remove the organic matter and pigment in the cabbage leaves.

[0051] (2) Take out the pretreated cabbage leaves, wash them with distilled water and dry them, then soak them in 50% Mn(NO 3 ) 2 The concentration of solution preparation is 0.15mol / L Mn(NO 3 ) 2 72 h in aqueous solution.

[0052] (3) Take out the soaked leaves, wash them with distilled water, and dry them at room temperature.

[0053] (4) Calcining the dried leaves, first in N 2 The temperature was raised to 600 °C under the atmosphere, and the heating rate was 10 °C min -1 , keep warm for 2 h, take it out and then raise the temperature to 700 °C in the air atmosphere, the heating rate is 10 °C·min -1 , and finally get the nanometer Mn 3 o 4 @C material.

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