The present application relates to the field of a reversible protonic ceramic electrochemical cell, specifically, to a double perovskite material and preparation method thereof, and a reversible protonic ceramic electrochemical cell. The expression for the double perovskite material is PrBa.sub.0.9Cs.sub.0.1Co.sub.2O.sub.6-, wherein is oxygen vacancy content. The present application also provides a preparation method for the double perovskite material and a reversible protonic ceramic electrochemical cell comprising the double perovskite material. The Cs.sup.+ doped double perovskite material provided by the present application has good stability, lower polarization impedance, and higher ORR/OER activity. The reversible protonic ceramic electrochemical cell provided by the present application has good stability, electrocatalytic activity, and electrochemical performance.

The current technology is directed to red and red-shade violet pigments with an hexagonal ABO.sub.3 structure of the form Y(In, M)O.sub.3 in which M is substituted for In in the trigonal bipyramidal B site of the ABO.sub.3 structure, and where M is a mixture containing Co.sup.2+ and charge compensating ions, or M is a mixture containing Co.sup.2+ and charge compensating ions, as well as other aliovalent and isovalent ions.

A composition includes a compound of the formula A.sub.xM.sub.yO.sub.z, wherein A is an A-site element and includes Ba, Ca, Cu, Dy, Er, Gd, La, Nd, Pr, Sm, Sr, Y, or Yb, or a combination thereof, M is an M-site element and includes Co, Cu, Fe, Mn, Ni, Ti, Sc, or P, or a combination thereof, and 0<x1, 0<y2, (3)z(4), and 1<<1. Use of the composition as a catalyst composition, for example an oxygen reduction reaction catalyst composition, in gas diffusion electrodes, and in metal-air batteries is also described.

The present disclosure relates to the field of new materials, and aims at providing a two-dimensional high-entropy metal oxide assembly with high thermal conductivity and a preparation method thereof. The two-dimensional high-entropy metal oxide assembly with the high thermal conductivity has a molecular formula of (Co.sub.0.3La.sub.0.6Er.sub.0.6Y.sub.0.7Mn.sub.0.4Ga.sub.0.4)O.sub.4. The two-dimensional high-entropy metal oxide assembly with the high thermal conductivity is in a short fiber shape with a length-diameter ratio of the short fiber of 5 to 7 and has a cross section of a regular triangle with the side length of the regular triangle of 100 to 300 nm. The present disclosure achieves one-dimensional high thermal conductivity of metal oxide assembly by means of orderly assembling of high-entropy oxide in the direction perpendicular to nanosheets. Meanwhile, the assembly enables uniform distribution of heterogeneous elements in the two-dimensional plane during the preparation process.

The present disclosure relates to the field of new materials, and aims at providing a two-dimensional high-entropy metal oxide assembly with high thermal conductivity and a preparation method thereof. The two-dimensional high-entropy metal oxide assembly with the high thermal conductivity has a molecular formula of (Co.sub.0.3La.sub.0.6Er.sub.0.6Y.sub.0.7Mn.sub.0.4Ga.sub.0.4)O.sub.4. The two-dimensional high-entropy metal oxide assembly with the high thermal conductivity is in a short fiber shape with a length-diameter ratio of the short fiber of 5 to 7 and has a cross section of a regular triangle with the side length of the regular triangle of 100 to 300 nm. The present disclosure achieves one-dimensional high thermal conductivity of metal oxide assembly by means of orderly assembling of high-entropy oxide in the direction perpendicular to nanosheets. Meanwhile, the assembly enables uniform distribution of heterogeneous elements in the two-dimensional plane during the preparation process.

A positive electrode material includes a lithium cobalt oxide with a P6.sub.3mc crystal structure. In a Raman spectrum of the positive electrode material, a peak height of a characteristic peak within a range of 490 cm.sup.15 cm.sup.1 is I.sub.1, and a peak height of a characteristic peak within a range of 592 cm.sup.15 cm.sup.1 is I.sub.2, satisfying 1<I.sub.2/I.sub.1<5.

A positive electrode material includes a lithium cobalt oxide with a P6.sub.3mc crystal structure. In a Raman spectrum of the positive electrode material, a peak height of a characteristic peak within a range of 490 cm.sup.15 cm.sup.1 is I.sub.1, and a peak height of a characteristic peak within a range of 592 cm.sup.15 cm.sup.1 is I.sub.2, satisfying 1<I.sub.2/I.sub.1<5.