Method for manufacturing porous silicon material, porous silicon material, and energy storage device

Abstract

To further prevent deterioration of charge-discharge characteristics of a Si-containing material.SOLUTION: The method of producing a porous silicon material according to the present invention, comprises a precursor production step of melting, rapidly cooling and coagulating a raw material including Al, Si and V to obtain a precursor of a silicon alloy, and a step of making the alloy porous by removing an Al component included in the silicon alloy, to obtain a porous silicon material.SELECTED DRAWING: None

Claims

1. A precursor step involves melting raw materials containing Al, Si, and V, rapidly cooling and solidifying them to obtain a silicon alloy precursor, A porosizing step to obtain a porous silicon material by removing the Al component contained in the silicon alloy, A method for producing a porous silicon material, comprising: a porous silicon material having a Si skeleton formed of a Si phase and a reinforcing phase which is a Si-V compound phase, and having an average pore diameter of 100 nm or less determined by a mercury intrusion method.

2. In the precursor step, the raw material used contains Si in an amount of 10 at% to 60 at% and V in an amount of 1 at% to 10 at% when the total amount of Al, Si, and V is 100 at%. A method for producing a porous silicon material according to claim 1.

3. In the aforementioned porosification step, the Al component is selectively removed by an acid or alkali. A method for producing a porous silicon material according to claim 1 or 2.

4. In the precursor step, the raw material is rapidly cooled and solidified by one of the following methods: gas atomization, water atomization, and roll quenching. A method for producing a porous silicon material according to claim 1 or 2.

5. In the aforementioned porosity-forming step, a porous silicon material having a porosity of 20 vol% or more, as determined by the mercury intrusion method, is obtained. A method for producing a porous silicon material according to claim 1 or 2.

6. It contains a Si phase and a Si-V compound phase, has a porosity of 20 vol% or more as determined by mercury intrusion, has a Si framework formed by the Si phase and a strengthening phase which is the Si-V compound phase, and has an average pore diameter of 100 nm or less as determined by mercury intrusion. Porous silicon material.

7. The proportion of the Si phase is 35 wt% or more and 98 wt% or less. The porous silicon material according to claim 6.

8. The pore size determined by the mercury intrusion method is between 1 nm and 300 nm. The porous silicon material according to claim 6 or 7.

9. The porosity determined by the mercury intrusion method is between 20 vol% and 85 vol%. The porous silicon material according to claim 6 or 7.

10. Contains Al in the range of over 0 at% and up to 10 at%. The porous silicon material according to claim 6 or 7.

11. The proportion of the Si phase is 50 wt% or more. The porous silicon material according to claim 6 or 7.

12. The aforementioned Si-V compound phase is VSi 2 The proportion of the phase is between 2 wt% and 55 wt%. The porous silicon material according to claim 6 or 7.

13. A positive electrode containing a positive electrode active material, A negative electrode comprising the porous silicon material described in claim 6 or 7 as a negative electrode active material, An ion-conducting medium interposed between the positive electrode and the negative electrode, which conducts lithium ions, Equipped with, Energy storage device.

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