Nano silicon/porous carbon composite anode material of lithium ion batteries as well as preparation method and application of composite anode material

Abstract

The invention discloses a nano silicon / porous carbon composite anode material of lithium ion batteries as well as a preparation method and an application of the composite anode material. The composite anode material is a core-shell structure material consisting of a porous nano silicon particle core and a porous carbon layer shell. The preparation method of the composite anode material comprises the steps as follows: carbonization treatment is performed after an organic polymer layer is coated on the surface of aluminum-silicon alloy powder, aluminum is removed by performing acid etching on a carbonization product, pore forming is performed on a carbon layer, and thus the nano silicon / porous carbon composite anode material is obtained. The preparation method is simple and low in cost, the mass production requirement is met, and the prepared composite anode material can be used for preparing the lithium ion battery and shows high capacity and excellent cycle and rate performance.

Description

technical field

[0001] The invention relates to a silicon-carbon composite material, in particular to a nano-silicon / porous carbon composite negative electrode material with a core-shell structure, and its application in the preparation of lithium-ion batteries with high capacity and excellent rate performance; it belongs to battery material technology field. Background technique

[0002] With the rapid expansion of population and the rapid development of economy, the electrochemical energy storage with lithium-ion battery as the main form has received great attention due to its environmental friendliness, long cycle life, small self-discharge, high energy density and high voltage. Attention, has been widely used in various portable electronic products. However, affected by the lithium storage mechanism and low capacity of existing graphite anode materials, it is difficult for current commercial lithium-ion batteries to meet the demand for high energy density such as electr...

Examples

Embodiment 1

[0048] Add 2g of aluminum-silicon alloy powder (commercial aluminum-silicon alloy powder with a particle size of 50-200nm) and 0.1g of PVP into 30mL and 20mL of absolute ethanol, respectively, and ultrasonically disperse for 5min to obtain a suspension of aluminum-silicon alloy in absolute ethanol and For the solution of PVP in absolute ethanol, the two were mixed, ultrasonicated for 5 minutes, magnetically stirred at 80°C and evaporated to dryness of absolute ethanol to obtain a solid powder. The powder was placed in a tube furnace in an argon atmosphere at 2°C / min and the temperature was raised to 600°C for 4h to obtain carbon-coated aluminum-silicon alloy powder. Weigh 2g of carbon-coated aluminum-silicon alloy powder and add it to 80mL of 4mol / L hydrochloric acid aqueous solution, stir and react at 40°C for 4h, filter, wash, dry and grind to obtain solid powder. Add the powder into 10wt% hydrofluoric acid aqueous solution, react at room temperature for 12h, centrifuge and ...

Embodiment 2

[0051] Add 2g of aluminum-silicon alloy powder (commercial aluminum-silicon alloy powder with a particle size of 50-200nm) and 0.3g of PVP into 30mL and 20mL of absolute ethanol, respectively, and ultrasonically disperse for 5min to obtain a suspension of aluminum-silicon alloy in absolute ethanol and For the solution of PVP in absolute ethanol, the two were mixed, ultrasonicated for 5 minutes, magnetically stirred at 80°C and evaporated to dryness of absolute ethanol to obtain a solid powder. The powder was placed in a tube furnace in an argon atmosphere at 2°C / min and the temperature was raised to 600°C for 4h to obtain carbon-coated aluminum-silicon alloy powder. Weigh 2g of carbon-coated aluminum-silicon alloy powder and add it to 80mL of 4mol / L hydrochloric acid aqueous solution, stir and react at 40°C for 4h, filter, wash, dry and grind to obtain solid powder. Add the powder into 10wt% hydrofluoric acid aqueous solution, react at room temperature for 12h, centrifuge and ...

Embodiment 3

[0054] Add 2g of aluminum-silicon alloy powder (commercial aluminum-silicon alloy powder with a particle size of 50-200nm) and 0.5g of PVP into 30mL and 20mL of absolute ethanol, respectively, and ultrasonically disperse for 5min to obtain a suspension of aluminum-silicon alloy in absolute ethanol and For the solution of PVP in absolute ethanol, the two were mixed, ultrasonicated for 5 minutes, magnetically stirred at 80°C and evaporated to dryness of absolute ethanol to obtain a solid powder. The powder was placed in a tube furnace in an argon atmosphere at 2°C / min and the temperature was raised to 600°C for 4h to obtain carbon-coated aluminum-silicon alloy powder. Weigh 2g of carbon-coated aluminum-silicon alloy powder and add it to 80mL of 4mol / L hydrochloric acid aqueous solution, stir and react at 40°C for 4h, filter, wash, dry and grind to obtain solid powder. Add the powder into 10wt% hydrofluoric acid aqueous solution, react at room temperature for 12h, centrifuge and ...

technical field

[0001] The invention relates to a silicon-carbon composite material, in particular to a nano-silicon / porous carbon composite negative electrode material with a core-shell structure, and its application in the preparation of lithium-ion batteries with high capacity and excellent rate performance; it belongs to battery material technology field. Background technique

[0002] With the rapid expansion of population and the rapid development of economy, the electrochemical energy storage with lithium-ion battery as the main form has received great attention due to its environmental friendliness, long cycle life, small self-discharge, high energy density and high voltage. Attention, has been widely used in various portable electronic products. However, affected by the lithium storage mechanism and low capacity of existing graphite anode materials, it is difficult for current commercial lithium-ion batteries to meet the demand for high energy density such as electr...

Examples

Embodiment 1

[0048] Add 2g of aluminum-silicon alloy powder (commercial aluminum-silicon alloy powder with a particle size of 50-200nm) and 0.1g of PVP into 30mL and 20mL of absolute ethanol, respectively, and ultrasonically disperse for 5min to obtain a suspension of aluminum-silicon alloy in absolute ethanol and For the solution of PVP in absolute ethanol, the two were mixed, ultrasonicated for 5 minutes, magnetically stirred at 80°C and evaporated to dryness of absolute ethanol to obtain a solid powder. The powder was placed in a tube furnace in an argon atmosphere at 2°C / min and the temperature was raised to 600°C for 4h to obtain carbon-coated aluminum-silicon alloy powder. Weigh 2g of carbon-coated aluminum-silicon alloy powder and add it to 80mL of 4mol / L hydrochloric acid aqueous solution, stir and react at 40°C for 4h, filter, wash, dry and grind to obtain solid powder. Add the powder into 10wt% hydrofluoric acid aqueous solution, react at room temperature for 12h, centrifuge and ...

Embodiment 2

[0051] Add 2g of aluminum-silicon alloy powder (commercial aluminum-silicon alloy powder with a particle size of 50-200nm) and 0.3g of PVP into 30mL and 20mL of absolute ethanol, respectively, and ultrasonically disperse for 5min to obtain a suspension of aluminum-silicon alloy in absolute ethanol and For the solution of PVP in absolute ethanol, the two were mixed, ultrasonicated for 5 minutes, magnetically stirred at 80°C and evaporated to dryness of absolute ethanol to obtain a solid powder. The powder was placed in a tube furnace in an argon atmosphere at 2°C / min and the temperature was raised to 600°C for 4h to obtain carbon-coated aluminum-silicon alloy powder. Weigh 2g of carbon-coated aluminum-silicon alloy powder and add it to 80mL of 4mol / L hydrochloric acid aqueous solution, stir and react at 40°C for 4h, filter, wash, dry and grind to obtain solid powder. Add the powder into 10wt% hydrofluoric acid aqueous solution, react at room temperature for 12h, centrifuge and ...

Embodiment 3

[0054] Add 2g of aluminum-silicon alloy powder (commercial aluminum-silicon alloy powder with a particle size of 50-200nm) and 0.5g of PVP into 30mL and 20mL of absolute ethanol, respectively, and ultrasonically disperse for 5min to obtain a suspension of aluminum-silicon alloy in absolute ethanol and For the solution of PVP in absolute ethanol, the two were mixed, ultrasonicated for 5 minutes, magnetically stirred at 80°C and evaporated to dryness of absolute ethanol to obtain a solid powder. The powder was placed in a tube furnace in an argon atmosphere at 2°C / min and the temperature was raised to 600°C for 4h to obtain carbon-coated aluminum-silicon alloy powder. Weigh 2g of carbon-coated aluminum-silicon alloy powder and add it to 80mL of 4mol / L hydrochloric acid aqueous solution, stir and react at 40°C for 4h, filter, wash, dry and grind to obtain solid powder. Add the powder into 10wt% hydrofluoric acid aqueous solution, react at room temperature for 12h, centrifuge and ...

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