US 7,537,682 B2
Methods for purifying carbon materials
Anne Dailly, Pasadena, Calif. (US); Channing Ahn, Pasadena, Calif. (US); Rachid Yazami, Los Angeles, Calif. (US); and Brent T. Fultz, Pasadena, Calif. (US)
Assigned to California Institute of Technology, Pasadena, Calif. (US); and Centre National de la Recherche Scientifique, Paris (France)
Filed on Mar. 16, 2005, as Appl. No. 11/81,841.
Claims priority of provisional application 60/553930, filed on Mar. 17, 2004.
Prior Publication US 2005/0205847 A1, Sep. 22, 2005
Int. Cl. C01B 31/02 (2006.01)
U.S. Cl. 205—555  [423/460; 423/461] 23 Claims
 
1. A method of purifying a sample containing a carbon material having a selected structure said method comprising the steps of:
providing said sample containing said carbon material having said selected structure and impurities comprising carbonaceous impurities, wherein said carbonaceous impurities comprise one or more carbon layers having a structure different than that of said selected structure;
exfoliating at least a portion of the carbon layers of said carbonaceous impurities, thereby generating exfoliated carbonaceous material; and
removing said impurities, thereby purifying said sample containing said carbon material having said selected structure,
wherein said step of exfoliating comprises adding an intercalant to said sample, wherein said intercalant inserts into interstitial sites in between multiple carbon layers comprising said carbonaceous impurities, interstitial sites between the carbon layers comprising said carbonaceous impurities and said carbon material having said selected structure, or both, thereby generating intercalated carbon layers, and wherein said intercalant is electrochemically intercalated into said carbon layers by application of an electric potential or electric current to said sample.