Manufacturing method of porous silicon material, porous silicon material, and power storage device
AssigneeToyota Jidosha Kabushiki Kaisha
InventorsHiroyuki Kawaura, Yasuhito Kondo, Ryo Suzuki, Hiroshi Nozaki, Jun Yoshida, Tetsuya Waseda, Mitsutoshi Otaki
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Abstract
The manufacturing method of a porous silicon material of the present disclosure includes a particle forming step of melting a raw material containing Al as a first element in an amount of 50% by mass or more and Si in an amount of 50% by mass or less to obtain a silicon alloy, a pore forming step of removing the first element from the silicon alloy to obtain a porous material, and a heat treatment step of heating the porous material to diffuse elements other than Si to a surface of the porous material.
Claims1
A power storage device comprising:
- a positive electrode that contains a positive electrode active material;
- a negative electrode that contains the porous silicon material as a negative electrode active material;
- and
- an ion conducting medium that is interposed between the positive electrode and the negative electrode and conducts carrier ions;
- wherein the porous silicon material comprises skeletal silicon with a three-dimensional network structure having voids that are formed of silicon having a lattice constant of 5.435 Å or less, wherein:
- an average porosity of the porous silicon material is in a range of 50% by volume or more and 95% by volume or less;
- a proportion of Si contained in the porous silicon material as an element excluding oxygen is 85% by mass or more;
- a proportion of Al contained in the porous silicon material as a first element is in a range of 15% by mass or less;
- and
- Al is present on a surface of the porous silicon material, wherein the Al present on the surface of the porous silicon material is an oxide.
Dependencies are inferred from the claim text.