ANODES OF POROUS SILICON PARTICLES
The present invention provides anode materials, methods of producing them, electrochemical cells, and lithium-ion batteries, where the anode material comprises porous silicon and carboxymethyl cellulose. In certain embodiments, the porous silica additionally comprises other materials, such as styrene-butadiene rubber.
1 . An anode material comprising:
porous silicon particles having an average pore diameter of from about 1 to about 500 nm; and
carboxymethyl cellulose (CMC).
2 . The anode material of claim 1 , wherein the porous silicon particle has a particle diameter from about 50 to about 250 nm.
3 . The anode material of claim 1 , wherein the porous silicon particle has a particle diameter from about 80 to about 150 nm.
4 . The anode material of claim 1 , further comprising styrene-butadiene rubber (SBR).
5 . A method for preparing the anode material of claim 1 , comprising:
contacting a silicon tetrahalide with a reducing agent under conditions sufficient to form a reduced silicon;
contacting the reduced silicon with an alkylating agent or an alkoxide to form an alkyl-capped silicon gel;
drying the alkyl-capped silicon gel;
contacting the dried, alkyl-capped silicon gel with hydrofluoric acid to form porous silicon particles having an average pore diameter from about 1 to about 500 nm; and
mixing the porous silicon particle with carboxymethyl cellulose (CMC), thereby preparing the anode material of claim 1 .
6 . The method of claim 5 , wherein the silicon tetrahalide is silicon tetrachloride.
7 . The method of claim 5 , wherein the reducing agent is sodium naphthalide.
8 . The method of claim 5 , wherein the alkylating agent is alkyl lithium.
9 . The method of claim 5 , wherein the alkylating agent comprises a C 1-6 alkyl.
10 . The method of claim 5 , further comprising heating the alkyl-capped silicon gel to remove the reducing agent.
11 . An anode material prepared by the method of claim 5 .
12 . A Li-ion battery comprising the anode material of claim 1 .
13 . Use of porous silicon particles and carboxymethyl cellulose for an anode material, wherein the silicon particles have an average pore diameter from about 1 nm to about 500 nm.