System and method for forming activated carbon aerogels and performing 3D printing
Making a carbon aerogel involves 3-D printing an ink to make a printed part, removing the solvent from the printed part, and carbonizing the printed part (with the solvent removed) to make the aerogel. The ink is based on a solution of a resorcinol-formaldehyde resin (RF resin), water, and an organic thickener. Advantageously, the RF resin contains an acid catalyst, which tends to produce carbon aerogels with higher surface areas upon activation than those produced from methods involving an ink composition containing a base catalyzed resin.
1. A 3-D printing ink, comprising:
water;
an organic thickener selected from the group consisting of water soluble cellulose derivatives, polyoxyalkylene compounds, polyvinyl alcohol, and mixtures thereof;
a resin that comprises resorcinol and formaldehyde;
an acid catalyst that catalyzes a reaction between the resorcinol and formaldehyde; and
a thixotropic additive;
wherein the 3-D printing ink does not contain graphene oxide; and
wherein the 3-D printing ink is a viscous thixotropic ink that is operable to gel after printing to form a printed part.
2. The 3-D printing ink of claim 1 , wherein the thixotropic additive comprises fumed silica.
3. The 3-D printing ink of claim 1 , wherein the organic thickener comprises hydroxypropylmethylcellulose.
4. The 3-D printing ink of claim 1 , wherein the organic thickener comprises a polyoxyalkylene compound.
5. The 3-D printing ink of claim 1 , comprising 10% to 60% by weight of the resin.