Polyimide bead materials and methods of manufacture thereof
Nanoporous carbon-based scaffolds or structures, and specifically carbon aerogels and their manufacture and use thereof are provided. Embodiments include a silicon-doped anode material for a lithium-ion battery, where the anode material includes beads of a polyimide-derived carbon aerogel. The carbon aerogel may further include silicon particles and accommodates expansion of the silicon particles during lithiation. The anode material provides optimal properties for use within the lithium-ion battery.
1. A method of forming a porous carbon composition in bead form, the method comprising:
providing an organogel precursor in an organic solvent;
initiating gelation of the organogel precursor to provide an organogel sol;
combining the organogel sol with a medium that is non-miscible with the organogel sol, wherein the combining comprises stirring under a high-shear condition, thereby forming droplets of organogel;
isolating the droplets of the organogel;
drying the droplets to yield porous organogel beads; and
pyrolyzing the porous organogel beads to yield the porous carbon composition in bead form, wherein the porous carbon composition has a porosity between about 10% and about 90%.
2. The method of claim 1 , wherein the organogel precursor is a polyamic acid comprising a tetracarboxylic acid and a multifunctional amine, and wherein the gelation is chemical imidization, thermal imidization, or a combination of chemical and thermal imidization.
3. The method of claim 2 , wherein the tetracarboxylic acid is selected from the group consisting of benzene-1,2,4,5-tetracarboxylic acid, [1,1′-biphenyl]-3,3′,4,4′-tetracarboxylic acid, 4,4′-oxydiphthalic acid, 4,4′-sulfonyldiphthalic acid, 4,4′-carbonyldiphthalic acid, 4,4′-(propane-2,2-diyl)diphthalic acid, 4,4′-(perfluoropropane-2,2-diyl)diphthalic acid, naphthalene-1,4,5,8-tetracarboxylic acid, 4-(2-(4-(3,4-dicarboxyphenoxy)phenyl)propan-2-yl)phthalic acid, perylene tetracarboxylic acid, and combinations thereof.
4. The method of claim 2 , wherein the multifunctional amine is an alkane diamine or an aryl diamine.
5. The method of claim 4 , wherein the aryl diamine is 1,4-phenylenediamine, 4,4′-diaminodiphenyl ether, 4,4′-methylenedianiline, or a combination thereof.
6. The method of claim 2 , wherein the chemical imidization comprises adding a dehydrating agent and an amine base.
7. The method of claim 6 , wherein the dehydrating agent is acetic anhydride and the amine base is pyridine.
8. The method of claim 1 , wherein the organic solvent is N,N-dimethylacetamide, N,N-dimethylformamide, N-methylpyrrolidone, tetrahydrofuran, or ethyl acetate.
9. The method of claim 1 , wherein the organic solvent further comprises water in an amount from about 100 to about 1500 parts per million (ppm), from about 500 to about 1200 ppm, or from about 500 to about 700 ppm.
10. The method of claim 1 , wherein the medium has a viscosity of about 100 to about 150 cP, and the organogel sol has a viscosity of about 5 to about 30 cP.
11. The method of claim 10 , wherein the medium is mineral oil, silicone oil, or a C5-C12 hydrocarbon.
12. The method of claim 11 , further comprising adding one or more surfactants to the medium.
13. The method of claim 1 , further comprising adding a low-viscosity solvent to the medium, wherein the low-viscosity solvent is a C1 to C3 alcohol.
14. The method of claim 1 , wherein stirring under a high-shear condition comprises stirring at a speed in a range from about 4000 to about 9000 rpm.
15. The method of claim 1 , wherein the drying comprises lyophilizing the organogel beads, exposing the organogel beads to elevated temperature conditions, contacting the organogel beads with supercritical fluid CO 2 , or contacting the organogel beads with liquid CO 2 and evaporating the CO 2 as a gas.
16. The method of claim 1 , wherein the beads of the porous carbon composition have a diameter in a range from about 1 micrometer to about 50 micrometers.
17. The method of claim 1 , wherein the porous carbon composition is a porous carbon-silicon composition comprising greater than about 10% by weight of silicon based on a total weight of the composition, the method further comprising providing silicon in a mixture with the organogel precursor in the organic solvent.
18. The method of claim 17 , wherein the porous carbon-silicon composition comprises from about 20% to about 65% by weight of silicon, based on a total weight of the composition.
19. The method of claim 17 , wherein the porous carbon-silicon composition comprises a pore structure, wherein the silicon is present at least partially within the pore structure, and wherein the pore structure comprises a fibrillar morphology and an array of pores that surround the silicon.