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.

A multi-composition fiber is provided including a primary fiber material and an elemental additive material deposited on grain boundaries between adjacent crystalline domains of the primary fiber material. A method of making a multi-composition fiber is also provided, which includes providing a precursor laden environment, and promoting fiber growth using laser heating. The precursor laden environment includes a primary precursor material and an elemental precursor material.

Provided herein is a method for preparing MXenes, such as Ti.sub.2CT.sub.x, Cr.sub.2CT.sub.x, and V.sub.2CT.sub.x, products prepared therefrom, and compositions and devices including the same.

Provided is a black-film-forming mixed powder containing: (A) a zirconium nitride powder that does not contain zirconium dioxide, a low-order oxide of zirconium, or a low-order oxynitride of zirconium; and (B) a titanium nitride powder or a titanium oxynitride powder, wherein the content ratio of (A) the zirconium nitride powder and (B) the titanium nitride powder or the titanium oxynitride powder is within the range of 90:10 to 25:75 in terms of mass ratio (A:B). When the light transmittance at a wavelength of 400 nm is X, the light transmittance at a wavelength of 550 nm is Y, and the light transmittance at a wavelength of 1,000 nm is Z in a spectrum of a dispersion in which the mixed powder is dispersed in a concentration of 50 ppm, X>10%, Y<10%, Z<16%, X/Y is 1.25 or more, and Z/Y is 2.0 or less.

Provided is a black-film-forming mixed powder containing: (A) a zirconium nitride powder that does not contain zirconium dioxide, a low-order oxide of zirconium, or a low-order oxynitride of zirconium; and (B) a titanium nitride powder or a titanium oxynitride powder, wherein the content ratio of (A) the zirconium nitride powder and (B) the titanium nitride powder or the titanium oxynitride powder is within the range of 90:10 to 25:75 in terms of mass ratio (A:B). When the light transmittance at a wavelength of 400 nm is X, the light transmittance at a wavelength of 550 nm is Y, and the light transmittance at a wavelength of 1,000 nm is Z in a spectrum of a dispersion in which the mixed powder is dispersed in a concentration of 50 ppm, X>10%, Y<10%, Z<16%, X/Y is 1.25 or more, and Z/Y is 2.0 or less.

A main object of the present disclosure is to provide an active material of which capacity properties are excellent. The present disclosure achieves the object by providing an active material to be used for a fluoride ion battery, the active material comprising: a composition represented by M.sup.1N.sub.x in which M.sup.1 is at least one kind of Cu, Ti, V, Cr, Fe, Mn, Co, Ni, Zn, Nb, In, Sn, Ta, W, and Bi, and x satisfies 0.05x3; or a composition represented by M.sup.2Ln.sub.yN.sub.z in which M.sup.2 is at least one kind of Cu, Ti, V, Cr, Fe, Mn, Co, Ni, Zn, Nb, In, Sn, Ta, W, and Bi, Ln is at least one kind of Sc, Y, and lanthanoid, y satisfies 0.1y3, and z satisfies 0.15z6.

A main object of the present disclosure is to provide an active material of which capacity properties are excellent. The present disclosure achieves the object by providing an active material to be used for a fluoride ion battery, the active material comprising: a composition represented by M.sup.1N.sub.x in which M.sup.1 is at least one kind of Cu, Ti, V, Cr, Fe, Mn, Co, Ni, Zn, Nb, In, Sn, Ta, W, and Bi, and x satisfies 0.05x3; or a composition represented by M.sup.2Ln.sub.yN.sub.z in which M.sup.2 is at least one kind of Cu, Ti, V, Cr, Fe, Mn, Co, Ni, Zn, Nb, In, Sn, Ta, W, and Bi, Ln is at least one kind of Sc, Y, and lanthanoid, y satisfies 0.1y3, and z satisfies 0.15z6.

Titanium nitride (TiN) nanofurnaces are fabricated in a method that involves anodization of a titanium (Ti) foil to form TiO.sub.2 nanocavities. After anodization, the TiO.sub.2 nanocavities are converted to TiN at 600 C. under ammonia flow. The resulting structure is an array of refractory (high-temperature stable) subwavelength TiN cylindrical cavities that operate as plasmonic nanofurnaces capable of reaching temperatures above 600 C. under moderate concentrated solar irradiation. The nanofurnaces show near-unity solar absorption in the visible and near infrared spectral ranges and a maximum thermoplasmonic solar-to-heat conversion efficiency of 68 percent.

Titanium nitride (TiN) nanofurnaces are fabricated in a method that involves anodization of a titanium (Ti) foil to form TiO.sub.2 nanocavities. After anodization, the TiO.sub.2 nanocavities are converted to TiN at 600 C. under ammonia flow. The resulting structure is an array of refractory (high-temperature stable) subwavelength TiN cylindrical cavities that operate as plasmonic nanofurnaces capable of reaching temperatures above 600 C. under moderate concentrated solar irradiation. The nanofurnaces show near-unity solar absorption in the visible and near infrared spectral ranges and a maximum thermoplasmonic solar-to-heat conversion efficiency of 68 percent.