Abstract: The invention provides a method for purifying silicon by means of a phase separation dealloying reaction, including: mixing a silicon raw material containing metallic or non-metallic impurities with magnesium powder first and then fully reacting under an inert atmosphere so as to obtain a first product; placing the first product in a nitrogen-containing atmosphere to undergo a nitriding reaction to form three-dimensional porous silicon and magnesium nitride distributed in pore channels thereof so as to obtain a second product, the impurities further being separated during the precipitation and crystallization of silicon, and being dissolved in the liquid-phase magnesium nitride; treating the second product by using acid-pickling, the magnesium nitride and impurities being dissolved and converted into a solution, and a solid product being high-purity porous silicon.

Abstract: The invention provides a method for purifying silicon by means of a phase separation dealloying reaction, including: mixing a silicon raw material containing metallic or non-metallic impurities with magnesium powder first and then fully reacting under an inert atmosphere so as to obtain a first product; placing the first product in a nitrogen-containing atmosphere to undergo a nitriding reaction to form three-dimensional porous silicon and magnesium nitride distributed in pore channels thereof so as to obtain a second product, the impurities further being separated during the precipitation and crystallization of silicon, and being dissolved in the liquid-phase magnesium nitride; treating the second product by using acid-pickling, the magnesium nitride and impurities being dissolved and converted into a solution, and a solid product being high-purity porous silicon.

Abstract: A preparation method of an ant nest like porous silicon for a lithium-ion battery comprises: (1) enabling a magnesium silicide raw material to react for 2-24 h in an ammonia gas or an atmosphere containing an ammonia gas at 600-900° C. to obtain a crude product containing porous silicon; and (2) subjecting the crude product containing porous silicon to an acid pickling treatment to obtain the ant nest like porous silicon. The preparation method has the advantages of simplicity and easiness. A large amount of porous silicon can be obtained by directly heating the magnesium silicide raw material in the ammonia gas or a mixed gas of the ammonia gas and an inert gas with a high yield.

Abstract: The present invention discloses a preparation method of ant nest like porous silicon for a lithium-ion battery, comprising: (1) enabling a magnesium silicide raw material to react for 2-24 h in an atmosphere containing ammonia gas at 600-900 DEG C. so as to obtain a crude product containing porous silicon (3Mg2Si+4NH3?3Si+2Mg3N2+6H2); the magnesium silicide raw material has a particle size of 0.2-10 ?m; and (2) subjecting the crude product containing porous silicon obtained in the step (1) to acid pickling so as to obtain ant nest like porous silicon for a lithium-ion battery. By improving the overall process flow of the porous silicon key preparation method as well as parameters and conditions of respective reaction steps, compared with the prior art, the preparation method has the advantage of simplicity and easiness, a large amount of porous micron silicon can be obtained by directly heating the obtained magnesium silicide in ammonia gas (or a mixed gas of ammonia gas and inert gas), and the yield is high.