Porous amorphous silicon, method for producing porous amorphous silicon, and secondary battery

Patent metadata

Field	Value
Publication number	US-2021371288-A1
Application number	US-201917042770-A
Country	US
Kind code	A1
Filing date	Sep 13, 2019
Priority date	Mar 26, 2019
Publication date	Dec 2, 2021
Grant date	—

Abstract

A porous amorphous silicon which enables improvement in battery performances such as charge/discharge efficiency and battery capacity when used as the anode material; a method for producing a porous amorphous silicon, capable of producing a porous amorphous silicon composed entirely of amorphous silicon at relatively low cost in a short time; and a secondary battery using the porous amorphous silicon as the anode material. A molten metal containing metal and silicon is cooled at a cooling rate of 106 K/sec or more to form an eutectic alloy including the metal and the silicon, and then the metal is selectively eluted from the eutectic alloy with an acid or an alkali to obtain a porous amorphous silicon. The porous amorphous silicon has a lamellar or columnar structure having a mean lamellar diameter or a mean column diameter of 1 nm to 100 nm.

First claim

1 . A porous amorphous silicon which has a lamellar or columnar structure having a mean lamellar diameter or a mean column diameter of 1 nm to 100 nm.

2 . The porous amorphous silicon according to claim 1 , which has a lamellar structure having a spacing between adjacent lamellae of 1 nm to 100 nm or a columnar structure having a spacing between adjacent columns of 1 nm to 100 nm.

3 . The porous amorphous silicon according to claim 1 , which has a mean porosity of 10% to 99%.

4 . The porous amorphous silicon according to claim 1 , wherein the mean lamellar diameter or the mean column diameter is 1 nm to 50 nm.

5 . The porous amorphous silicon according to claim 1 , which has a bicontinuous structure.

6 . A method for producing a porous amorphous silicon, which comprises cooling a molten metal containing metal and silicon at a cooling rate of 10 6 K/sec or more to form an eutectic alloy comprising the metal and the silicon, and selectively eluting the metal from the eutectic alloy with an acid or an alkali to obtain a porous amorphous silicon.

7 . The method for producing a porous amorphous silicon according to claim 6 , wherein the eutectic alloy is produced by a single roll rapid quenching method or a twin roll rapid quenching method, and has a ribbon or foil shape having a mean thickness of 0.1 μm to 1 mm.

8 . The method for producing a porous amorphous silicon according to claim 6 , wherein the eutectic alloy is produced by a gas atomization method or a water atomization method, and has a powder shape having a mean lamellar diameter of 10 nm to 30 μm.

9 . The method for producing a porous amorphous silicon according to claim 6 , wherein a phase of the silicon in the structure of the eutectic alloy has a domain size of 1 nm to 100 nm.

10 . The method for producing a porous amorphous silicon according to claim 6 , wherein a phase of the metal in the structure of the eutectic alloy has a domain size of 1 nm to 100 nm.

11 . The method for producing a porous amorphous silicon according to claim 6 , wherein a phase of the silicon in the structure of the eutectic alloy has a domain size of 1 nm to 50 nm.

12 . The method for producing a porous amorphous silicon according to claim 6 , wherein the eutectic alloy is an Al—Si alloy.

13 . The method for producing a porous amorphous silicon according to claim 12 , which contains an atomic percentage of Si between 1% to 50%.

14 . The method for producing a porous amorphous silicon according to claim 6 , wherein the eutectic alloy is an Fe—Si alloy, an Ni—Si alloy, a Cr—Si alloy, an Ag—Si alloy or a Cu—Si alloy.

15 . The method for producing a porous amorphous silicon according to claim 14 , which contains an atomic percentage of Si between 50% to 90%.

16 . The method for producing a porous amorphous silicon according to claim 6 , wherein the eutectic alloy is a two- or multi-component eutectic alloy represented by M 1 -Si (M 1 represents one or more elements selected from Al, Ag, As, Au, Be, Ca, Cr, Cu, Mg, Pd, Pt, Y, Co, Fe, Mn, Ti and Zr).

17 . The method for producing a porous amorphous silicon according to claim 6 , wherein the eutectic alloy is a three- or multi-component eutectic alloy represented by M 2 -Al—Si (M 2 represents one or more elements selected from Ca, Cu, Ge, P, Mn, Na, Sb, Sn, Sc, Sr and Ti).

18 . A secondary battery whose anode material comprises the porous amorphous silicon according to claim 1 .

Assignees

• Univ Tohoku

Inventors

• Okada Junpei
• Nakayama Koji
• Wada Takeshi

Classifications

• C01P2006/90

  Other properties not specified above · CPC title

• C01P2004/04

  obtained by TEM, STEM, STM or AFM · CPC title

• C01P2004/03

  obtained by SEM · CPC title

• C01P2002/02

  Amorphous compounds · CPC title

• B22F2998/10

  Processes characterised by the sequence of their steps · CPC title