Porous silicon block material with multistage directional holes and preparation method of porous silicon block material

The invention belongs to the field of porous silicon preparation, and particularly relates to a porous silicon block material with multistage directional holes and a preparation method of the porous silicon block material. The porous silicon block material with directional and multistage holes has a straight hole morphology; the aperture is 20-100mu m; the porosity is distributed at 50%-90%; a lot of micro-pores with the apertures being smaller than 2nm and mesopores with the apertures of 2-50nm are distributed on the wall of the straight hole; and the preparation method comprises the following steps: firstly, synthesizing porous silicon powder employing magnesium thermal reaction; and then preparing the porous silicon block material with hierarchical pores employing a tert butyl alcohol freeze-drying method. The material prepared by the method disclosed by the invention has the characteristic of straight hole morphology; micro-pores and mesopores are distributed on the hole wall; and the problems that the existing method for preparing porous silicon is single in aperture distribution, and cannot balance the mass transfer efficiency and high superficial area are solved.