The present disclosure relates to a composition that includes a perovskite crystal, where the perovskite crystal is in the form of a powder, and the perovskite crystal is semiconducting and photovoltaically active.

A main object of the present disclosure is to provide a new active material that can be used in a fluoride ion battery. The present disclosure achieves the object by providing an active material to be used in a fluoride ion battery, the active material comprising: a crystal phase including an infinite layer structure, and represented by A.sub.pB.sub.qO.sub.r, provided that A is at least one of an alkali earth metal element and a rare earth element, B is a transition metal element, p satisfies 0.8≤p≤1, q satisfies 0.8≤q≤1, and r satisfies 1.5≤r≤2.5.

The present invention relates to a composite of a cobalt-based perovskite material with a negative thermal expansion material, and a preparation method of the same, and a solid oxide fuel cell (SOFC) comprising the same, and belongs to the technical field of fuel cells. In the present invention, a negative thermal expansion material is introduced into a cobalt-based perovskite oxide to successfully prepare an SOFC cathode material with excellent electrochemical performance and low thermal expansivity. The composite electrode achieves prominent mechanical tolerance in SOFC, which can moderate a volume change during the whole calcination process and enable a smooth transition to a high-temperature stage. The composite electrode has a thermal expansion coefficient (TEC) only of 12.9×10.sup.−6 K.sup.−1, which is perfectly matched with that of an SDC electrolyte. In addition, the composite shows excellent oxygen reduction reaction (ORR) activity, high TEC, and extremely-excellent anti-CO.sub.2 poisoning performance.

The present invention provides: a ferrite particle containing a crystal phase component containing a perovskite crystal represented by the compositional formula RZrO.sub.3 (where R is an alkaline earth metal element); and an electrophotographic developer carrier core material, an electrophotographic developer carrier, and an electrophotographic developer containing the ferrite particles.

The invention provides a process for the preparation of a bismuth sodium titanate (BNT) compound of formula (I) wherein A is one or more of Bi, Na, Li, K, Mg, Ca, Sr, Ba, La, Al, Cu, Eu, Ag and Zn; B is one or more of Ti, Nb, Ta, Zr, Fe, Nd, Eu and Co; 0<x<0.8; 0<y<0.8; and −0.1<z<0.1; said process comprising spray pyrolysis of a solution comprising Bi ions, Na ions, Ti ions and, if present, metal (A) and/or metal (B) ions.

A light-absorbing material includes a compound, wherein the compound has a perovskite crystal structure represented by the formula AMX.sub.3 where a Cs.sup.+ ion is located at an A-site, a Ge.sup.2+ ion is located at an M-site, and I.sup.− ions are located at X-sites, and at least a part of the compound has an orthorhombic perovskite crystal structure. An X-ray diffraction pattern of the compound measured using Cu Kα radiation may have a first peak at a diffraction angle (2θ) of 25.4° or more and 25.8° or less and a second peak at a diffraction angle (2θ) of 24.9° or more and 25.3° or less, and an intensity of the first peak may be 30% or more of an intensity of the second peak.

Disclosed is a catalyst having a perovskite structure in the form of ABO.sub.3, in which the number of ion moles at the A site has an excess ratio compared to the number of ion moles at the B site. The present invention exhibits an oxygen catalytic activity improved by about 3 times in an oxygen evolution reaction and by about 40% in an oxygen reduction reaction, compared to those of an existing LaNiO.sub.3 perovskite catalyst. Further, since the metallic conductivity is not significantly changed compared to the existing LaNiO.sub.3 perovskite oxide, there is an advantage in that a carbon support need not be used when the present invention is used as a catalyst in a battery positive electrode.

Use of a barium titanate based coating liquid composition comprising: (a) a sol-gel source material containing (i) at least a barium component selected from a group consisting of barium alkoxides, hydrolyzates of barium alkoxides and condensates of hydrolyzates of barium alkoxides and (ii) at least a titanium component selected from a group consisting of titanium alkoxides, hydrolyzates of titanium alkoxides and condensates of hydrolyzates of titanium alkoxides; and (b) a β-keto ester compound expressed by general formula (1) shown below: ##STR00001## where R.sub.1 and R.sub.2 independently represent respective alkyl groups having not less than 1 and not more than 6 carbon atoms.

A main object of the present disclosure is to provide an anode active material having excellent electron conductivity and ion conductivity. The present disclosure achieves the object by providing an anode active material to be used for a lithium ion battery, the anode active material including at least a Sr element and a S element, and a Perovskite type of crystal phase belonging to a space group of I4/mmm, and a molar ratio of the S element with respect to the Sr element is larger than 0.1.

The present disclosure provides a method for preparing a perovskite quantum dot film by one-step crystallization, and belongs to the field of perovskite quantum dot material technology. The present disclosure uses adamantanemethylamine and hydrohalic acid as ligands, first mixes a cesium halide, a lead halide, and the ligands with a solvent to obtain a precursor solution, then deposits the precursor solution on a substrate, and then heats the substrate to obtain the CsPbX.sub.3 perovskite quantum dot film. The present disclosure uses adamantanemethylamine and hydrohalic acid as the ligands, which can quickly coat the perovskite, complex with the CsPbX.sub.3 perovskite, and directly form the perovskite quantum dot via a strong steric effect. Further, the present disclosure is simple and inexpensive, can directly obtain a high-quality perovskite quantum dot film with a thickness of more than 500 nm by one-step crystallization.