A method of forming a carbonized composition includes providing an organic composition, forming a protective layer over the organic composition, increasing temperature to carbonize the organic composition and for a period of time to form the carbonized composition, and removing the protective layer from the carbonized composition.

Porous three-dimensional networks of polyimide and porous three-dimensional networks of carbon and methods of their manufacture are described. For example, polyimide aerogels are prepared by mixing a dianhydride and a diisocyanate in a solvent comprising a pyrrolidone and acetonitrile at room temperature to form a sol-gel material and supercritically drying the sol-gel material to form the polyimide aerogel. Porous three-dimensional polyimide networks, such as polyimide aerogels, may also exhibit a fibrous morphology. Having a porous three-dimensional polyimide network undergo an additional step of pyrolysis may result in the three dimensional network being converted to a purely carbon skeleton, yielding a porous three-dimensional carbon network. The carbon network, having been derived from a fibrous polyimide network, may also exhibit a fibrous morphology.

The present invention relates to a method for preparation of a powder comprising at least one carbide of at least one metal, comprising the steps consisting of: (a) preparing a solution comprising at least one organic gelling agent and at least one inorganic salt of at least one metal in a solvent; (b) modifying the pH of the solution prepared in step (a) in such a way as to precipitate said at least one metal and to obtain a colloidal suspension comprising nanoparticles of oxyhydroxides of said at least one metal; (c) removing the solvent from the colloidal suspension obtained in step (b) by which means a precursor of at least one carbide of at least one metal is obtained; and (d) subjecting the precursor obtained in step (c) to a thermal treatment in order to transform same into a powder comprising at least one carbide of at least one metal. The present invention also relates to the powder thus prepared and the various uses thereof.

The present disclosure is directed to compositions comprising at least one layer having first and second surfaces, each layer comprising: a substantially two-dimensional array of crystal cells, each crystal cell having an empirical formula of M′.sub.2M″nX.sub.n+1, such that each X is positioned within an octahedral array of M′ and M″; wherein M′ and M″ each comprise different Group 11113, WE, VB, or VIB metals; each X is C, N, or a combination thereof; n=1 or 2; and wherein the M′ atoms are substantially present as two-dimensional outer arrays of atoms within the two-dimensional array of crystal cells; the M″ atoms are substantially present as two-dimensional inner arrays of atoms within the two-dimensional array of crystal cells; and the two dimensional inner arrays of M″ atoms are sandwiched between the two-dimensional outer arrays of M′ atoms within the two-dimensional army of crystal cells.

The present disclosure is directed to compositions comprising at least one layer having first and second surfaces, each layer comprising: a substantially two-dimensional array of crystal cells, each crystal cell having an empirical formula of M′.sub.2M″nX.sub.n+1, such that each X is positioned within an octahedral array of M′ and M″; wherein M′ and M″ each comprise different Group 11113, WE, VB, or VIB metals; each X is C, N, or a combination thereof; n=1 or 2; and wherein the M′ atoms are substantially present as two-dimensional outer arrays of atoms within the two-dimensional array of crystal cells; the M″ atoms are substantially present as two-dimensional inner arrays of atoms within the two-dimensional array of crystal cells; and the two dimensional inner arrays of M″ atoms are sandwiched between the two-dimensional outer arrays of M′ atoms within the two-dimensional army of crystal cells.

Provided are methods of stabilizing MXene compositions using polyanionic salts so as to reduce the oxidation of the MXenes. Also provided are stabilized MXene compositions.

Provided are methods of stabilizing MXene compositions using polyanionic salts so as to reduce the oxidation of the MXenes. Also provided are stabilized MXene compositions.

The present disclosure relates to a graphene-nanoflower shaped MXene composite material, preparation method and application thereof, which belongs to the field of negative electrode materials for supercapacitors. In the present disclosure, a space-time shaping femtosecond laser is utilized to process MXene target in graphene oxide nanoflake dispersion, so as to synthesize a graphene-nanoflower shaped MXene composite material in one-step. This nanoflower shaped MXene has adjustable size and morphology and an extremely large specific surface area; when it is used in an electrode material for supercapacitors, the supercapacitor exhibits an extremely high specific capacitance and good cycle stability. This method utilizes a space-time shaping femtosecond laser to synthesize the graphene-nanoflower shaped MXene composite material, which is highly controllable, and can be used to uniformly prepare the material in large-scale. It has provided a new way for synthesis of materials.

A carbonized composition is formed by a process including providing an organic composition formed into a predetermined configuration, forming a protective layer over the organic composition, increasing temperature to carbonize the organic composition and form the carbonized composition, and removing the protective layer from the carbonized composition, wherein the carbonized composition has substantially the predetermined configuration. In a number of embodiments, the organic composition includes a nucleic acid. In a number of embodiments, the organic composition consists of a nucleic acid. The nucleic acid may, for example, be DNA.

A carbonized composition is formed by a process including providing an organic composition formed into a predetermined configuration, forming a protective layer over the organic composition, increasing temperature to carbonize the organic composition and form the carbonized composition, and removing the protective layer from the carbonized composition, wherein the carbonized composition has substantially the predetermined configuration. In a number of embodiments, the organic composition includes a nucleic acid. In a number of embodiments, the organic composition consists of a nucleic acid. The nucleic acid may, for example, be DNA.