A negative thermal expansion material having a negative thermal expansion coefficient according to the present invention is represented by Zr.sub.2-aM.sub.aS.sub.xP.sub.2O.sub.12+δ, where M is at least one selected from Ti, Ce, Sn, Mn, Hf, Ir, Pb, Pd, and Cr; a is 0≤a<2; x is 0.4≤x≤1; and δ is a value defined as to satisfy a charge neutral condition. The present invention makes it possible to provide a negative thermal expansion material, a composite material and a method for producing a negative thermal expansion material that can realize reduction in cost and density reduction.

Trace hydrogen may be removed from a dry gas by passing the dry gas at a temperature from about 0° C. to about 60° C. through at least one layer of a first hopcalite catalyst to produce product gas that is at least substantially free of hydrogen, wherein the first hopcalite catalyst has a molar ratio of copper to manganese of more than 0.55. Advantages include increase hydrogen capacity, lower feed and regeneration temperatures and lower sensitivity to carbon dioxide than equivalent processes using standard hopcalite catalyst having a Cu/Mn molar ratio from 0.45 to 0.55.

The present invention discloses a preparation method for a spherical Zn-Mn metal compound. The preparation method comprises the following steps: adding a metal ion solution to a weak acid carbon dot solution; and then, adding a sodium carbonate solution to the above solution at an oil bath while stirring to obtain a spherical Zn-Mn metal carbonate compound. The present invention proposes that using water-soluble or ethanol-soluble carbon dots as a carrier and polyvinylpyrrolidone as a surfactant to prepare the spherical Zn-Mn metal compound, a novel preparation method for the Zn-Mn metal compound is formed. The prepared material may be applied to a lithium ion battery and may further be applied to application researches in the field of synthesis of other electrochemical energy sources or photocatalytic materials.

A hydrothermal synthesis for LiFePO.sub.4 is provided. First, each raw material solution is prepared using a degassed water in advance, second, those solution are mixed by dripping in a fixed order, and then those materials are reacted in a hydrothermal synthesis, so that LiFePO.sub.4 is obtained in a predesigned form.

A battery includes a positive electrode including a positive electrode active material, a negative electrode, and an electrolytic solution including an additive. The positive electrode active material includes a compound having a crystal structure belonging to a space group FM3-M and represented by Compositional Formula (1): Li.sub.xMe.sub.yO.sub.αF.sub.β, where, Me is one or more elements selected from the group consisting of Mn, Co, Ni, Fe, Al, B, Ce, Si, Zr, Nb, Pr, Ti, W, Ge, Mo, Sn, Bi, Cu, Mg, Ca, Ba, Sr, Y, Zn, Ga, Er, La, Sm, Yb, V, and Cr; and subscripts x, y, α, and β satisfy the following requirements: 1.7≤x≤2.2, 0.8≤y≤1.3, 1≤α≤2.5, and 0.5≤β≤2. The additive is at least one selected from dinitrile compounds and diisocyanate compounds.

A battery includes a positive electrode including a positive electrode active material, a negative electrode, and an electrolytic solution including an additive. The positive electrode active material includes a compound having a crystal structure belonging to a space group FM3-M and represented by Compositional Formula (1): Li.sub.xMe.sub.yO.sub.αF.sub.β, where, Me is one or more elements selected from the group consisting of Mn, Co, Ni, Fe, Al, B, Ce, Si, Zr, Nb, Pr, Ti, W, Ge, Mo, Sn, Bi, Cu, Mg, Ca, Ba, Sr, Y, Zn, Ga, Er, La, Sm, Yb, V, and Cr; and subscripts x, y, α, and β satisfy the following requirements: 1.7≤x≤2.2, 0.8≤y≤1.3, 1≤α≤2.5, and 0.5≤β≤2. The additive is at least one selected from dinitrile compounds and diisocyanate compounds.

The invention relates to a solid body of a compound of formula Zn.sub.1-t-eT.sub.tE.sub.eO.sub.1-yY.sub.y, wherein the compound has a wurtzite structure and wherein T represents one or more transition metals, selected from one or more of Mn, Cd, Cr, Fe, Co and Ni; E represents one or more alkaline earth metals, selected from one or more of Be, Mg, Ca, Sr and Ba; Y represents one or more chalcogens, selected from S, Se, Te; tis a value in the region of 0 to <1; e is a value from 0 to <1, and y is a value from 0 to <1.

The invention relates to active electrode materials and to methods for the manufacture of active electrode materials. Such materials are of interest as active electrode materials in lithium-ion or sodium-ion batteries. The invention provides a method of making an active electrode material, the method comprising: providing a mixed niobium oxide; combining the mixed niobium oxide with a carbon precursor to form an intermediate material, wherein the carbon precursor comprises polyaromatic sp.sup.2 carbon and is selected from pitch carbons, graphene oxide, and mixtures thereof; and heating the intermediate material under reducing conditions to pyrolyse the carbon precursor forming a carbon coating on the mixed niobium oxide and introducing oxygen vacancies into the mixed niobium oxide, thereby forming the active electrode material.

Provided are a zinc ion battery positive electrode material, a preparation method therefor, and an application thereof. The preparation method for the zinc ion battery positive electrode material includes: performing a sintering treatment on manganese carbonate to obtain the zinc ion battery positive electrode material. In this method, through a heat treatment of manganese carbonate, a zinc ion battery positive electrode material with high performance can be obtained. In addition, the method requires low raw material and simple preparation processes, and thus it is suitable for industrial production.

Provided are a zinc ion battery positive electrode material, a preparation method therefor, and an application thereof. The preparation method for the zinc ion battery positive electrode material includes: performing a sintering treatment on manganese carbonate to obtain the zinc ion battery positive electrode material. In this method, through a heat treatment of manganese carbonate, a zinc ion battery positive electrode material with high performance can be obtained. In addition, the method requires low raw material and simple preparation processes, and thus it is suitable for industrial production.