A material for a negative electrode active material having capability of achieving excellent cycle performance while maintaining satisfactory initial efficiency (initial capacity), a production method for the material, a composition for a negative electrode, using the material, a negative electrode, and a secondary battery. A core-shell structure that includes the following components (A) and (B), and satisfies the following conditions (i) and (ii): (A): a core containing at least Si (silicon), O (oxygen) and C (carbon) as a constituent element, and containing crystalline carbon and non-crystalline carbon as a constituent; and (B): a shell encapsulating the core, and including a SiOC structure having a graphene layer, and (i): having an atomic composition represented by formula SiO.sub.xC.sub.y (0.5<x<1.8, 1.0<y<5.0), and (ii): having a predetermined value of less than 1.0×10.sup.5 Ω.Math.cm in specific resistance determined by powder resistance measurement.

An osmotic energy conversion system includes a housing having a first inlet and a second inlet, an MXene lamellar membrane located inside the housing and configured to divide the housing into a first chamber and a second chamber, and first and second electrodes placed in the first and second chambers, respectively, and configured to collect electrical energy generated by a salinity-gradient formed by first and second liquids across the MXene lamellar membrane. The first chamber is configured to receive the first liquid at the first inlet and the second chamber is configured to receive the second liquid at the second inlet. The first liquid has a salinity lower than the second liquid, and the MXene lamellar membrane includes plural nanosheets of MXene stacked on top of each other.

The invention relates to a method for producing a non-oxide ceramic powder comprising a nitride, a carbide, a boride or at least one MAX phase with the general composition Mn+1AXn, where M=at least one element from the group of transition elements (Sc, Ti, V, Cr, Zr, Nb, Mo, Hf and Ta), A=at least one A group element from the group (Si, Al, Ga, Ge, As, Cd, In, Sn, Tl and Pb), X=carbon (C) and/or nitrogen (N) and/or boron (B), and n=1, 2 or 3. According to the invention, corresponding quantities of elementary starting materials or other precursors are mixed with at least one metal halide salt (NZ), compressed (pellet), and heated for synthesis with a metal halide salt (NZ). The compressed pellet is first enveloped with another metal halide salt, compressed again, arranged in a salt bath and heated therewith until the melting temperature of the salt is exceeded. Optionally, melted silicate can be added, which prevents the salt from evaporating at high temperatures. Advantageously, the method can be carried out in the presence of air.

An osmotic energy conversion system includes a housing having a first inlet and a second inlet, an MXene lamellar membrane located inside the housing and configured to divide the housing into a first chamber and a second chamber, and first and second electrodes placed in the first and second chambers, respectively, and configured to collect electrical energy generated by a salinity-gradient formed by first and second liquids across the MXene lamellar membrane. The first chamber is configured to receive the first liquid at the first inlet and the second chamber is configured to receive the second liquid at the second inlet. The first liquid has a salinity lower than the second liquid, and the MXene lamellar membrane includes plural nanosheets of MXene stacked on top of each other.

A multicomponent carbide has at least five transition metals, and a valence electron concentration (VEC) is greater 8.80 electrons. Preferred off-equiatomic multicomponent carbides have five transition metals and a VEC of more than 8.80. Preferred equiatomic multicomponent carbides have five transition metals and a VEC of 9.00 or greater. The valence electron configuration is important for its relationship to the mechanical properties of carbides. Since carbon forms four bonds, when there are more than four valence electrons available from the metals, there are excess electrons in the system. This increases metallic character of bonding and therefore allows for more ductility and higher toughness.

A multicomponent carbide has at least five transition metals, and a valence electron concentration (VEC) is greater 8.80 electrons. Preferred off-equiatomic multicomponent carbides have five transition metals and a VEC of more than 8.80. Preferred equiatomic multicomponent carbides have five transition metals and a VEC of 9.00 or greater. The valence electron configuration is important for its relationship to the mechanical properties of carbides. Since carbon forms four bonds, when there are more than four valence electrons available from the metals, there are excess electrons in the system. This increases metallic character of bonding and therefore allows for more ductility and higher toughness.

The present disclosure is directed to nanocomposites comprising a co-sintered composition of a MXene crystal form composition and an inorganic oxide, or oxide-type ceramic and methods of making and using the same.

A method for producing a metal nitride and/or a metal carbide, a metal nitride and/or metal carbide optionally produced according to the method, and the use of the metal nitride and/or carbide in catalysis optionally catalytic hydroprocessing. Optionally, the method comprises: i) contacting at least one metal oxide comprising at least one first metal M.sup.1 with a cyanometallate comprising at least one second metal M.sup.2 to form a reaction mixture; and, ii) subjecting the reaction mixture to a temperature of at least 300° C. for a reaction period. Optionally, the metal nitride and/or metal carbide is a metal nitride comprising tungsten nitride.

A method for producing a metal nitride and/or a metal carbide, a metal nitride and/or metal carbide optionally produced according to the method, and the use of the metal nitride and/or carbide in catalysis optionally catalytic hydroprocessing. Optionally, the method comprises: i) contacting at least one metal oxide comprising at least one first metal M.sup.1 with a cyanometallate comprising at least one second metal M.sup.2 to form a reaction mixture; and, ii) subjecting the reaction mixture to a temperature of at least 300° C. for a reaction period. Optionally, the metal nitride and/or metal carbide is a metal nitride comprising tungsten nitride.

A complex carbide for mining and mineral processing applications that are subject to severe additional metal, with the additional metal being a transition metal.