An object is to provide an electrode active material that can provide an alkali metal battery having a longer charge/discharge life and a higher capacity. The problem is solved by means of an electrode active material for an alkali metal battery, represented by formula: A.sub.a1MS.sub.a2X.sub.a3 wherein A is selected from Li and Na; M is selected from V, Nb, Ta, Ti, Zr, Hf, Cr, Mo, and W which are group 4 to 6 elements; X is selected from F, Cl, Br, I, CO.sub.3, SO.sub.4, NO.sub.3, BH.sub.4, BF.sub.4, PF.sub.6, ClO.sub.4, CF.sub.3SO.sub.3, (CF.sub.3SO.sub.2).sub.2N, (C.sub.2F.sub.5SO.sub.2).sub.2N, (FSO.sub.2).sub.2N, and [B(C.sub.2O.sub.4).sub.2]; a1 is 1 to 9; a2 is 2 to 6; when a3 is 3 and a3 is 0, a2 is not 4; and when M does not include V, a3>0.

There is provided a secondary battery including a cathode, an anode including an anode active material layer and a coating film, and an electrolytic solution. The anode active material layer includes a titanium-containing compound, and a surface of the anode active material layer is coated with the coating film. The electrolytic solution includes one or more of unsaturated cyclic carbonate esters. Porosity of a portion of the anode active material layer measured with use of a mercury intrusion technique is within a range from 30% to 50% both inclusive. The portion of the anode active material layer is cut together with a portion of the coating film from a surface of the coating film to a depth of 10 μm.

A CoVO.sub.x composite electrode and method of making is described. The composite electrode comprises a substrate with an average 0.5-5 μm thick layer of CoVO.sub.x having pores with average diameters of 2-200 nm. The method of making the composite electrode involves contacting the substrate with an aerosol comprising a solvent, a cobalt complex, and a vanadium complex. The CoVO.sub.x composite electrode is capable of being used in an electrochemical cell for water oxidation.

An electrode active material for lithium-ion secondary batteries that has a sufficiently high initial capacity, improved charge-and-discharge cycle characteristics, and improved coulombic efficiency in the mid-term charge-and-discharge cycles can be obtained by a phosphorus-containing low-crystalline vanadium sulfide comprising vanadium, phosphorus, and sulfur as constituent elements, the composition ratio of the phosphorus to the vanadium (P/V) being 0.1 to 1.0 in terms of the molar ratio, the composition ratio of the sulfur to the vanadium (S/V) being 4.00 to 10.00 in terms of the molar ratio.

In general, the present disclosure is directed to methods for synthesizing vanadium oxide nanobelts, as well as the corresponding chemical composition of the vanadium oxide nanobelts. Also described are materials which can incorporate the vanadium oxide nanobelts, such as including the vanadium oxide nanobelts as a cathode material for use in energy storage applications (e.g., batteries). The vanadium oxide nanobelts described herein display structural characteristics that may provide improved diffusion and/or charge transfer between ions. Thus, batteries incorporating implementations of the current disclosure may demonstrate improved properties such as higher capacity retention over charge discharge cycling.

A layered double hydroxide is represented by the following formula (I): Ni.sup.2+.sub.1−(x+y+z)Fe.sup.3+.sub.xV.sup.3+.sub.yCo.sup.3+.sub.z(OH).sub.2A.sup.n−.sub.(x+y+z)/n.Math.mH.sub.2O . . . (I). In one embodiment, in the formula (I), (x+y+z) is from 0.2 to 0.5, “x” represents more than 0 and 0.3 or less, “y” represents from 0.04 to 0.49, and “z” represents more than 0 and 0.2 or less.

A lithium vanadium oxide crystal and usage thereof that can achieve further excellent electrochemical characteristics are provided. New lithium vanadium oxide crystal is a lithium vanadium oxide crystal which is Li.sub.3VO.sub.4 to which tetravalent metal species M is doped, in which the lithium vanadium oxide crystal is represented by a chemical formula of Li.sub.3+1V.sub.1−xM.sub.xO.sub.4 and includes only a single crystal structure with γ-phase as Li.sub.3VO.sub.4 under a temperature environment including normal temperature, and the tetravalent metal species M is included in a ratio of x≥0.2.

A CoVO.sub.x composite electrode and method of making is described. The composite electrode comprises a substrate with an average 0.5-5 μm thick layer of CoVO.sub.x having pores with average diameters of 2-200 nm. The method of making the composite electrode involves contacting the substrate with an aerosol comprising a solvent, a cobalt complex, and a vanadium complex. The CoVO.sub.x composite electrode is capable of being used in an electrochemical cell for water oxidation.

A method of preparing bismuth vanadate particles is described. The bismuth vanadate particles prepared via ultrasonication and hydrothermal treatment exhibit controlled morphology (e.g., octahedral shape) and crystallinity (e.g., tetragonal crystal symmetry). A photoelectrode containing bismuth vanadate particles and a method of using the photoelectrode in a photoelectrochemical cell for water splitting is also provided.

The present disclosure broadly relates to a process for preparing aqueous solutions of vanadium sulfates or aqueous solutions of transition metal sulfates. More specifically, but not exclusively, the present disclosure relates to a direct electrochemical process in which a suspension, obtained by slurrying transition metals oxides such as oxides of vanadium, oxides of iron, oxides of cobalt, oxides of nickel, oxides of chromium, oxides of manganese, oxides of titanium, oxides of cerium, oxides of praseodymium, oxides of europium, oxides of terbium, oxides of uranium, oxides of plutonium, or their mixtures thereof with sulfuric acid as carrier fluid, is reduced electrochemically inside the cathode compartment of an electrolyzer to produce an aqueous solution of vanadium sulfates or of transition metal sulfates. Simultaneously, oxidizing co-products are produced in the anode compartment.