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

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