Dispersions containing graphenic carbon nanoparticles and dispersant resins
Graphenic carbon nanoparticles that are dispersed in solvents through the use of dispersant resins are disclosed. The graphenic carbon nanoparticles may be milled prior to dispersion. The dispersant resins may comprise a polymeric dispersant resin comprising an addition polymer comprising the residue of a vinyl heterocyclic amide, an addition polymer comprising a homopolymer, a block (co)polymer, a random (co)polymer, an alternating (co)polymer, a graft (co)polymer, a brush (co)polymer, a star (co)polymer, a telechelic (co)polymer, or a combination thereof. The solvents may be aqueous, non-aqueous, inorganic and/or organic solvents. The dispersions are highly stable and may contain relatively high loadings of the graphenic carbon nanoparticles.
1 . A dispersion comprising:
an organic solvent comprising N-methyl-2-pyrrolidone;
graphenic carbon nanoparticles;
a polymeric dispersant resin comprising an addition polymer comprising a homopolymer, a block (co)polymer, a random (co)polymer, an alternating (co)polymer, a graft (co)polymer, a brush (co)polymer, a star (co)polymer, a telechelic (co)polymer, or a combination thereof; wherein the addition polymer comprises a residue of an alkyl ester of (meth)acrylic acid containing from 8 to 22 carbon atoms in the alkyl group.
2 . The dispersion of claim 1 , wherein the dispersion has an instability index of less than 0.5.
3 . The dispersion of claim 1 , wherein the graphenic carbon nanoparticles are present in the dispersion in an amount greater than 3 weight percent based on the total weight of the dispersion.
4 . The dispersion of claim 3 , wherein the instability index is less than 0.3.
5 . The dispersion of claim 1 , wherein the alkyl ester of (meth)acrylic acid containing from 8 to 22 carbon atoms in the alkyl group comprises lauryl methacrylate or stearyl acrylate.
6 . The dispersion of claim 1 , wherein the addition polymer further comprises a residue of a vinyl heterocyclic amide comprising vinyl pyrrolidone or polyvinyl pyrrolidone.
7 . The dispersion of claim 1 , wherein the graphenic carbon nanoparticles have an average aspect ratio of greater than 3:1 and a Raman 2D:G peak ratio of at least 1:1.
8 . The dispersion of claim 7 , wherein the graphenic carbon particles have a B.E.T. specific surface area of at least 70 square meters per gram.
9 . The dispersion of claim 1 , wherein the graphenic carbon nanoparticles are thermally produced at a temperature of at least 3,500° C.
10 . The dispersion of claim 9 , wherein the graphenic carbon nanoparticles are turbostratic and comprise 4 or more stacked layers.
11 . The dispersion of claim 1 , wherein the graphenic carbon nanoparticles are milled.
12 . The dispersion of claim 1 , wherein a weight ratio of the graphenic carbon nanoparticles to the dispersant resin is from 0.5:1 to 15:1.
13 . A lithium ion battery electrode comprising:
a lithium-containing active material or lithium-reactive particles; and
the dispersion of claim 1 .
14 . A method of dispersing graphenic carbon nanoparticles in an organic solvent comprising:
mixing a dispersant resin into the solvent to form a mixture, wherein the solvent comprises N-methyl-2-pyrrolidone, and wherein the dispersant resin comprises an addition polymer comprising the residue of a vinyl heterocyclic amide, an addition polymer comprising a homopolymer, a block (co)polymer, a random (co)polymer, an alternating (co)polymer, a graft (co)polymer, a brush (co)polymer, a star (co)polymer, a telechelic (co)polymer, or a combination thereof; wherein the addition polymer comprises a residue of an alkyl ester of (meth)acrylic acid containing from 8 to 22 carbon atoms in the alkyl group; and
mixing the graphenic carbon nanoparticles into the solvent and dispersant resin mixture.
15 . The method of claim 14 , further comprising milling the graphenic carbon nanoparticles prior to the mixing of the graphenic carbon nanoparticles into the solvent and dispersant resin mixture.
16 . The method of claim 14 , wherein the graphenic carbon nanoparticles have an average aspect ratio of greater than 3:1 and a Raman 2D:G peak ratio of at least 1:1.