Disclosed herein is a stabilised Na-ion oxide P3 phase of formula (I): P3-Na.sub.xM.sub.yO.sub.z Where, x>0.66, 0.8≤y≤1.0, z≤2; and M is selected from one or more of the group consisting of a 3d transition metal, a 4d transition metal, Al, Mg, B, Si, Sn, Sr and Ca. The stabilised Na-ion oxide P3 phase of formula (I) may be particularly useful as an active material in a Na-ion battery.

Electromagnetic Electromagnetic wave absorbing particles including cesium tungsten oxide represented by a general formula Cs.sub.xW.sub.1-yO.sub.3-z (0.2≤x≤0.4, 0<y≤0.4, and 0<z≤0.46) and having an orthorhombic crystal structure or a hexagonal crystal structure are provided.

This positive electrode active substance for a non-aqueous electrolyte secondary battery contains a lithium-transition metal composite oxide which has a crystal structure belonging to the space group Fm-3m and is represented by the compositional formula Li.sub.xMn.sub.yM.sub.aO.sub.bF.sub.c (in the formula: M is at least one type of metal element excluding Mn; x+y+a=b+c=2; 1<x≤1.35; 0.4≤y≤0.9; 0≤a≤0.2; and 1.3≤b≤1.8). In addition, the lattice constant a of the lithium-transition metal composite oxide is 4.09-4.16.

A secondary battery includes a positive electrode, a negative electrode, and an electrolytic solution. The positive electrode includes a positive electrode active material layer. The positive electrode active material layer includes a lithium-nickel composite oxide of a layered rock-salt type.

There is provided a method for collecting and reusing an active material from positive electrode scrap. The method of reusing a positive electrode active material of the present disclosure includes (a-1) immersing a positive electrode scrap comprising an active material layer on a current collector into a basic solution to separate the active material layer from the current collector, (a-2) thermally treating the active material layer in air for thermal decomposition of a binder and a conductive material in the active material layer, and collecting an active material in the active material layer, (b) washing the active material collected from the step (a-2) with a lithium compound solution which is basic in an aqueous solution and drying, and (c) annealing the active material washed from the step (b) with a lithium precursor to obtain a reusable active material.

A semiconductor phosphide injection synthesis system and a control method are provided, which belong to the technical field of preparation of semiconductor phosphides. The semiconductor phosphide injection synthesis system includes a furnace body, a shielding carrier box arranged above the furnace body by virtue of a lifting mechanism, a phosphorus source carrier arranged in the shielding carrier box, an injection pipe arranged below the phosphorus source carrier, and a crucible arranged at an inner bottom of the furnace body in a matched manner. The phosphorus source carrier includes a phosphorus source carrier main body, a phosphorus source carrier upper cover, a heating element base arranged at an inner bottom of the phosphorus source carrier main body, and a heating element arranged on the heating element base; a heat insulation layer is wrapped on an outer wall of the phosphorus source carrier; and an induction coil is arranged between the heat insulation layer and an inner wall of the shielding carrier box. By improving a device and method, the system stability can be improved, and an entire synthesis system achieves quantitative synthesis, which lowers the risk of explosion of the phosphorus source carrier.

A treatment process for crystallizing a metal sulfate involving pre-treating a feedstock comprising calcium, magnesium, and/or lithium impurities, the pre-treating involving pre-leaching the feedstock in the presence of a lixiviant, selectively extracting a first portion of any of the impurities from the feedstock, and forming a leached solution comprising an uncrystallized metal sulfate and any remaining impurities; and/or refining the leached solution and removing a second portion of any of the remaining impurities; and crystallizing the uncrystallized metal sulfate from the leached solution to form a crystallized metal sulfate. So processed, the crystallized metal sulfate may be battery-grade or electroplating-grade.

A process for removing impurities from a crystallized metal sulfate, including contacting crystallized metal sulfate with a liquor rich in metal sulfate. The metal may be cobalt, nickel, or manganese, and the impurities may be magnesium or calcium. The liquor rich in metal sulfate may be an overflow liquor from crystallization of the metal sulfate, and said overflow liquor may be subject to one or more impurities removal steps prior to contacting the crystallized metal sulfate, such that the overflow liquor contains lower levels of impurities than the crystallized metal sulfate to be contacted. A counter-current wash circuit may be used to remove impurities from a crystallized metal sulfate, whereby a plurality of washing tanks are configured to receive crystallized metal sulfate in a sequence, and washing liquor in reverse of said sequence.

A lithium transition metal oxide electrode including an additional metal is provided herein as well electrochemical cells including the lithium transition metal oxide electrode and methods of making the lithium transition metal oxide electrode. The lithium transition metal oxide electrode includes a first electroactive material including Li.sub.1+aNi.sub.bMn.sub.cM.sub.dO.sub.2, where 0.05≤a≤0.6; 0.01≤b≤0.5; 0.1≤c≤0.9; zero (0)≤d≤0.3; b+c+d=1 or a+b+c+d=1; and M represents an additional metal, such as W, Mo, V, Zr, Nb, Ta, Fe, Al, Mg, Si, or a combination thereof.

The present disclosure belongs to the technical field of lithium battery cathode materials, and discloses a preparation method of multiple carbon-coated high-compaction lithium iron manganese phosphate, comprising the following steps: (1) synthesizing a carbon and vanadium co-doped ferromanganese phosphate precursor through a co-precipitation method, sintering, and removing crystal water to obtain an anhydrous ferromanganese phosphate precursor; (2) adding lithium phosphate, a supplemental phosphorus source, an organic carbon source, a dopant and deionized water, and performing ball milling, wet sanding, spray drying and sintering to obtain an intermediate material; and (3) adding deionized water and the organic carbon source, then performing ball milling, sanding, spray drying, sintering and air jet pulverization to obtain multiple carbon-coated high-compaction lithium iron manganese phosphate.