Embodiments of a method for synthesizing water-soluble metal oxide nanoparticles are disclosed. In one embodiment, the method includes heating a first reaction mixture at a predetermined temperature for a predetermined time duration with continuous stirring to obtain a second reaction mixture that comprises water-soluble metal oxide nanoparticles of a first size. The first reaction mixture includes a reactant and a polyol. The method further includes adding a first predetermined amount of the reactant to the second reaction mixture to obtain a third reaction mixture. The method further includes heating the third reaction mixture at the predetermined temperature for the predetermined time duration with continuous stirring to obtain a fourth reaction mixture comprising water-soluble metal oxide nanoparticles of a second size. The reactant is Fe(acac).sub.3 and the polyol is diethylene glycol (DEG) for synthesizing water-soluble iron oxide nanoparticles.

The present invention relates to a ferrite particle containing a crystal phase component containing a perovskite crystal represented by a compositional formula: RZrO.sub.3 (provided that R represents an alkaline earth metal element), having a surface roughness Rz of 2.0 m or more and 4.5 m or less, and satisfying the following formulas: 6.5log H.sub.10008.5 and 0.80log H.sub.1000/log H.sub.1001.00. The ferrite particle can be used as an electrophotographic developer carrier core material. In addition, an electrophotographic developer carrier and an electrophotographic developer can be obtained.

The present invention relates to a ferrite particle containing a crystal phase component containing a perovskite crystal represented by a compositional formula: RZrO.sub.3 (provided that R represents an alkaline earth metal element), having a surface roughness Rz of 0.8 m or more and 3.5 m or less, and having a standard deviation Rz of the surface roughness Rz falling in a range represented by the following formula 0.15RzRz0.60Rz. The ferrite particle can be used as an electrophotographic developer carrier core material. In addition, an electrophotographic developer carrier and an electrophotographic developer can be obtained.

This disclosure provides lithium supplement materials, including Li.sub.5Fe.sub.1-xM.sub.xO.sub.4 and a cladding layer disposed on a surface of Li.sub.5Fe.sub.1-xM.sub.xO.sub.4. In Li.sub.5Fe.sub.1-xM.sub.xO.sub.4, where M is at least one of Ni, Mn, Ru, Cr, Cu, Nb, Al, Mg, Ca, Ga, Ti, and Mo, and 0x0.2. The cladding layer includes M-doped zinc oxide or M-doped composite oxide based on zinc oxide, and Mis an ion capable of forming a substitutional solid solution with zinc oxide or composite oxide based on zinc oxide.

The present invention relates to a ferrite particle containing a crystal phase component containing a perovskite-type crystal represented by a composition formula of RZrO3 (wherein R is an alkaline earth metal element), and a Mg content of 0.45 mass % or less. The present invention also relates to a carrier core material for an electrophotographic developer, containing the ferrite particle; a carrier for an electrophotographic developer, containing the ferrite particle and a resin coating layer provided on a surface of the ferrite particle; and an electrophotographic developer containing the carrier for an electrophotographic developer and a toner.

The present application discloses a positive electrode active material satisfying the chemical formula L.sub.xNa.sub.yM.sub.zCu.sub.Fe.sub.Mn.sub.O.sub.2+0.5X.sub. and a preparation method therefor, a sodium ion battery and an apparatus including such battery, wherein L is a doping element at alkali metal site, M is a doping element at transition metal site, and X is a doping element at oxygen site, 0x<0.35, 0.65y1, 0<0.3, 0<0.5, 0<0.5, 0.030.03, 00.1, z+++=1, mx+y+nz+2+3+4=2(2+), m is the valence state of L, and n is the valence state of M; and the pH of the positive electrode active material is 10.5-13, wherein L is a doping element at alkali metal site, M is a doping element at transition metal site, and X is a doping element at oxygen site.

Provided are: a ferrite powder whereby, when the ferrite powder is applied in a composite material, dropping out of ferrite particles is suppressed without moldability and filling ability being compromised; a ferrite resin composite material; and an electromagnetic shielding material, an electronic material, or an electronic component. This ferrite powder includes at least spherical or polyhedral ferrite particles in which a step structure is provided on surfaces thereof, the step structure having a polyhedral outline in the surfaces of the ferrite particles.

The present application discloses a positive electrode active material satisfying the chemical formula L.sub.xNa.sub.yM.sub.zCu.sub.Fe.sub.Mn.sub.O.sub.2+0.5X.sub. and a preparation method therefor, a sodium ion battery and an apparatus including such battery, wherein L is a doping element at alkali metal site, M is a doping element at transition metal site, and X is a doping element at oxygen site, 0x<0.35, 0.65y1, 0<0.3, 0<0.5, 0<0.5, 0.030.03, 00.1, z+++=1, mx+y+nz+2+3+4=2(2+), m is the valence state of L, and n is the valence state of M; and the pH of the positive electrode active material is 10.5-13, wherein L is a doping element at alkali metal site, M is a doping element at transition metal site, and X is a doping element at oxygen site.