The present application discloses a positive electrode active material and its preparation method, a sodium ion battery and an apparatus containing the sodium ion battery. The positive electrode active material satisfies a chemical formula of Na.sub.1-xCu.sub.hFe.sub.kMn.sub.lM.sub.mO.sub.2-y wherein M is one or more selected from Li, Be, B, Mg, Al, K, Ca, Ti, Co, Ni, Zn, Ga, Sr, Y, Nb, Mo, In, Sn, and Ba, 0<x≤0.33, 0<h≤0.24, 0≤k≤0.32, 0<l≤0.68, 0≤m≤0.1, h+k+l+m=1, 0≤y≤0.2, and the positive electrode active material has a water content of 6000 ppm or less.

Embodiments of the present disclosure are directed to hydrogen-selective oxygen carrier materials and methods of using hydrogen-selective oxygen carrier materials. The hydrogen-selective oxygen carrier material may comprise a core material, which includes a redox-active transition metal oxide; a shell material, which includes one or more alkali transition metal oxides; and a support material. The shell material may be in direct contact with at least a majority of an outer surface of the core material. At least a portion of the core material may be in direct contact with the support material. The hydrogen-selective oxygen carrier material may be selective to combust hydrogen in an environment that includes hydrogen and hydrocarbons.

Nanowires useful as heterogeneous catalysts are provided. The nanowire catalysts are useful in a variety of catalytic reactions, for example, the oxidative coupling of methane to C2 hydrocarbons. Related methods for use and manufacture of the same are also disclosed.

Embodiments of the present disclosure are directed to methods of producing a hydrogen- selective oxygen carrier material comprising combining one or more core material precursors and one or more shell material precursors to from a precursor mixture and heat-treating the precursor mixture at a treatment temperature to form the hydrogen-selective oxygen carrier material. The treatment temperature is greater than or equal to 100° C. less than the melting point of a shell material, and the hydrogen- selective oxygen carrier material comprises a core comprising a core material and a shell comprising the shell material. The shell material may be in direct contact with at least a majority of an outer surface of the core material.

Methods for regenerating degraded cathode particles in lithium-ion batteries are provided through a combination of hydrothermal treatment of cycled electrode particles followed by short thermal annealing. The methods provide for directly regenerating high-performance LiCoO2 (LCO) and LiNixCoyMnzO2 (NCM) cathodes. Combining hydrothermal treatment with short thermal annealing to regenerate degraded LCO particles provides successful reconstruction of stoichiometric composition and desired crystalline structure from severely degraded cathode materials, and in further embodiments, successful regeneration of degraded NCM cathodes is demonstrated, which regenerates degraded NCM particles with electrochemical performance reaching that of new cathode materials.

A positive electrode active material includes secondary particles. The secondary particles include a plurality of primary particles. The primary particles include a lithium-containing composite metal oxide. Inside the secondary particles, an electron conducting oxide is disposed at at least a part of a grain boundary between the primary particles. The electron conducting oxide has a perovskite structure.

Preparation, characterization, and an electrochemical study of Mg.sub.0.1V.sub.2O.sub.5 prepared by a novel sol-gel method with no high-temperature post-processing are disclosed. Cyclic voltammetry showed the material to be quasi-reversible, with improved kinetics in an acetonitrile-, relative to a carbonate-, based electrolyte. Galvanostatic test data under a C/10 discharge showed a delivered capacity >250 mAh/g over several cycles. Based on these results, a magnesium anode battery, as disclosed, would yield an average operating voltage 3.2 Volts with an energy density 800 mWh/g for the cathode material, making the newly synthesized material a viable cathode material for secondary magnesium batteries.

According to one embodiment, there is provided an active material. The active material includes secondary particles. The secondary particles include first primary particles and second primary particles. The first primary particles include an orthorhombic Na-containing niobium-titanium composite oxide. The second primary particles include at least one selected from the group consisting of a carbon black, a graphite, a titanium nitride, a titanium carbide, a lithium titanate having a spinel structure, a titanium dioxide having an anatase structure, and a titanium dioxide having a rutile structure.

A positive electrode for a rechargeable battery, comprising a lithium metal oxide powder having a layered crystal structure and having the formula Li.sub.xTm.sub.yHm.sub.zO.sub.6, with 3x4.8, 0.60y2.0, 0.60z2.0, and x+y+z=6, wherein Tm is one or more transition metals of the group consisting of Mn, Fe, Co, Ni, and Cr; wherein Hm is one or more metals of the group consisting of Zr, Nb, Mo and W. The lithium metal oxide powder may comprise dopants and have the formula Li.sub.xTm.sub.yHm.sub.zM.sub.mO.sub.6 A, wherein A is either one or more elements of the group consisting of F, S or N; and M is either one or more metal of the group consisting of Ca, Sr, Y, La, Ce and Zr, with either >0 or m>0, 0.05, m0.05 and x+y+z+m=6.

Li-ion battery materials, such as Li-ion cathodes, are provided that have spinels characterized by a close-packed face-centered-cubic rocksalt-type structure and spinel-like ordered TM (the TM preferably occupying one of the two octahedral sites 16c and 16d) that favor fast Li transport kinetics. Such spinels have a larger deviation from a normal spinel and have a formula. Li.sub.1+xTM.sub.2-yO.sub.4-zF.sub.z where 0.2x1, 0.2y0.6, and 0z0.8; and TM is Mn, Ni, Co, Al, Sc, Ti, Zr, Mg, Nb, or a mixture thereof. The spinels achieve a higher gravimetric energy density than traditional spinels while still retaining high capacity at an extremely fast charging/discharging rate.