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Composite silicon based electrode material, preparation method and application thereof

An electrode material, silicon-based technology, applied in battery electrodes, circuits, electrical components, etc., can solve the problems of poor electrode cycle performance, low Coulomb efficiency, solvent instability, etc., to suppress capacity decay, reduce volume change rate, First Coulomb Efficiency Effect

Inactive Publication Date: 2017-11-24
PEKING UNIV
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  • Abstract
  • Description
  • Claims
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AI Technical Summary

Problems solved by technology

However, the huge volume change (>300%) of the silicon-based negative electrode material in the process of lithium intercalation and deintercalation makes it extremely easy to pulverize and fall off, and the electrode cycle performance is extremely poor; and the silicon-based negative electrode also has the problem of low initial Coulombic efficiency.
The existing technology improves the first-time Coulombic efficiency of silicon-based materials by pre-lithiation. However, the pre-lithiation electrode materials are not stable, such instability includes unstable storage in the environment, and instability to solvents in the battery assembly process. , and capacity instability during charge-discharge cycles, which inhibits the development of silicon-based electrode materials

Method used

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  • Composite silicon based electrode material, preparation method and application thereof
  • Composite silicon based electrode material, preparation method and application thereof
  • Composite silicon based electrode material, preparation method and application thereof

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preparation example Construction

[0046] In a second aspect, the present invention provides a method for preparing a composite silicon-based electrode material, comprising the following steps: firstly oxidize the pre-lithiated silicon-based core, and then carry out carbon coating. The composite silicon-based electrode material can be obtained after the graphene layer is formed outside the nucleus. The preparation method of the above-mentioned composite silicon-based electrode material is simple in process, high in controllability, and suitable for industrial continuous production. First, the pre-lithiated silicon-based core is oxidized to form an oxide layer on the surface of the pre-lithiated silicon-based core. Graphene provides a large number of nucleation centers for the nucleation and growth of graphene, and then carbon coating is carried out to obtain the composite silicon-based electrode material. The composite silicon-based electrode material prepared by this method has high environmental stability , s...

Embodiment 1

[0064] A composite silicon-based electrode material, mainly composed of a pre-lithiated silicon-based core and a graphene layer coated on the outside of the pre-lithiated silicon-based core. The pre-lithiated silicon-based core is mainly composed of a silicon source and a Lithium reagent was prepared.

[0065] The above-mentioned composite silicon-based electrode material is mainly prepared by the following method:

[0066] (a) Mix silicon monoxide powder (with a particle size of 5 μm) and LiH evenly in a mortar with a mass ratio of 7:1, place it in an atmospheric tube furnace under an argon atmosphere, and calcinate at 800 °C for 1 h, The pre-lithiated silicon-based core is obtained, and its XRD pattern is as follows figure 1 shown;

[0067] (b) Carry out oxidation treatment in the weak oxidation atmosphere with the pre-lithiated silicon-based core obtained in step (a), the weak oxidation atmosphere is O 2 and argon gas mixture, where O 2 The volume fraction is 1%, the fl...

Embodiment 2

[0071] A composite silicon-based electrode material, mainly composed of a pre-lithiated silicon-based core and a graphene layer coated on the outside of the pre-lithiated silicon-based core. The pre-lithiated silicon-based core is mainly composed of a silicon source and a Lithium reagent was prepared.

[0072] The above-mentioned composite silicon-based electrode material is mainly prepared by the following method:

[0073] (a) Mix silicon monoxide powder (with a particle size of 10 nm) and LiH evenly in a mortar with a mass ratio of 3:1, place in an atmospheric tube furnace under an argon atmosphere, and calcinate at 400°C for 2 hours;

[0074] (b) Carry out oxidation treatment in the weak oxidation atmosphere with the pre-lithiated silicon-based core obtained in step (a), the weak oxidation atmosphere is O 2 and argon gas mixture, where O 2 The volume fraction is 10%, the flow rate of the mixed gas is 20sccm; the oxidation temperature is 400°C, and the oxidation time is 5m...

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Abstract

Relating to the field of electrode materials, the invention in particular provides a composite silicon based electrode material, a preparation method and application thereof. The composite silicon based electrode material is mainly composed of a pre-lithiated silicon based core and a graphene layer coating the pre-lithiated silicon based core. The composite silicon based electrode material has the advantages of high environmental stability, good inertness to solvent, high initial coulomb efficiency and good cyclic stability, has no change after storage in the air for 24h or more, has initial coulomb efficiency up to 90% or more, shows good inertness to water based solvents and oil based solvents, and has a capacity retention ratio up to92% or more after 20 cycles.

Description

technical field [0001] The invention relates to the field of electrode materials, in particular to a composite silicon-based electrode material, a preparation method and an application thereof. Background technique [0002] Rechargeable lithium-ion batteries have the advantages of high specific energy, good cycle stability, wide operating temperature range, low self-discharge rate and good environmental compatibility, and have been widely used in portable electronic devices, mobile communications, power tools, smart home appliances and other fields , and gradually expanded to hybrid electric vehicles, plug-in electric vehicles, pure electric vehicles, grid energy storage and renewable energy storage and other fields. Existing commercial lithium-ion batteries mainly use carbon-based materials as negative electrode active materials, especially graphite materials. The theoretical electrochemical capacity of such materials is limited, only 372mAh / g, which is difficult to meet th...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/36H01M4/38H01M4/62H01M10/0525
CPCH01M4/366H01M4/386H01M4/628H01M10/0525Y02E60/10
Inventor 刘忠范史刘嵘彭海琳庞春雷任建国黄友元
Owner PEKING UNIV
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