A cathode material comprises bimetal-doped barium cobaltite-based perovskite and a bi-directional protonic ceramic fuel cell comprising the same. In a cathode material according to an embodiment, barium cobaltite is doped with scandium (Sc) and tantalum (Ta), and the cathode material is represented by the following Formula 1:

BaSc.sub.xTa.sub.0.2?xCo.sub.0.8O.sub.3??[Formula 1] where X is 0.001<X<0.199, ? is 0<?<2.

Mixed-metal oxides and lithiated mixed-metal oxides are disclosed that involve compounds according to, respectively, Ni.sub.xMn.sub.yCo.sub.zMe.sub.O.sub. and Li.sub.1+Ni.sub.xMn.sub.yCo.sub.zMe.sub.O.sub.. In these compounds, Me is selected from B, Na, Mg, Al, Si, K, Ca, Sc, Ti, V, Cr, Fe, Cu, Zn, Ga, Ge, Zr, Nb, Mo, Ru, Ag, In, and combinations thereof; 0x1; 0y1; 0z<1; x+y+z>0; 00.5; and x+y+>0. For the mixed-metal oxides, 15. For the lithiated mixed-metal oxides, 0.11.0 and 1.93. The mixed-metal oxides and the lithiated mixed-metal oxides include particles having an average density greater than or equal to 90% of an ideal crystalline density.

A high-rate lithium cobaltate cathode material, which contains a multi-channel network formed by fast ionic conductor Li.sub.M.sub.O.sub., mainly consists of lithium cobaltate. The lithium cobaltate is melted together with the fast ionic conductor Li.sub.M.sub.O.sub. in the form of primary particles to form secondary particles. Besides, the lithium cobaltate is embedded in the multi-channel network formed by fast ionic conductor Li.sub.M.sub.O.sub.. The element M in Li.sub.M.sub.O.sub. is one or more of Ti, Zr, Y, V, Nb, Mo, Sn, In, La, W and 14, 15, 212. The lithium cobaltate cathode material is mainly obtained by uniformly mixing cobaltous oxide impregnated with a hydroxide of M and lithium source, then by the sintering reaction in an air atmosphere furnace at a high temperature. The product of the present invention can greatly promote the lithium ion conductivity of the lithium cobaltate cathode material during the charging and discharging process of the lithium-ion battery, and improve the rate performance of the material.

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 relates to a metal oxide powder, a method of preparing the same, and a lithium secondary battery using the same, which comprises: a metal oxide powder is represented by Formula (1),

Li.sub.x(M.sub.1-m-zA.sub.mD.sub.z)O.sub.tFormula (1) in the above Formula (1), 0.85x1.2, 0m0.01, 0<z0.04, 1.85t2.2, M is selected from the group consisting of Ni, Co, Mn and combinations thereof, A is selected from the group consisting of Mg, Ca, Sr, Ba and combinations thereof, D is selected from the group consisting of Ti, Zr, Ce, Ge, Sn and combinations thereof, and E is an average oxidation number of A and D, and E>3.5.

There is provided a thermoelectric conversion material which is characterized by being composed of a sintered body of plate-like crystals of a composite oxide represented by general formula (2) Bi.sub.fCa.sub.gM.sup.3.sub.hCo.sub.iM.sup.4.sub.jO.sub.k, and by having a density of 4.0-5.1 g/cm.sup.3. This thermoelectric conversion material is also characterized in that: when observed by SEM, the ratio of the plate-like crystals of a composite oxide represented by general formula (2) having an inclination in the major axis direction within 020 relative to the surface of the thermoelectric conversion material is 60% or more on the number basis; the average length of the lengths of the plate-like crystals of a composite oxide represented by general formula (2) is 20 m or more; and the aspect ratio of the plate-like crystals of a composite oxide represented by general formula (2) is 20 or more.

Mixed-metal oxides and lithiated mixed-metal oxides are disclosed that involve compounds according to, respectively, Ni.sub.xMn.sub.yCo.sub.zMe.sub.O.sub. and Li.sub.1+Ni.sub.xMn.sub.yCo.sub.zMe.sub.O.sub.. In these compounds, Me is selected from B, Na, Mg, Al, Si, K, Ca, Sc, Ti, V, Cr, Fe, Cu, Zn, Ga, Ge, Zr, Nb, Mo, Ru, Ag, In, and combinations thereof; 0x1; 0y1; 0z<1; x+y+z>0; 00.5; and x+y+>0. For the mixed-metal oxides, 15. For the lithiated mixed-metal oxides, 0.11.0 and 1.93. The mixed-metal oxides and the lithiated mixed-metal oxides include particles having an average density greater than or equal to 90% of an ideal crystalline density.

The present invention provides a positive active material for use in a secondary lithium battery, a method for preparing the positive active material and a secondary lithium battery containing the positive active material. The positive active material includes a core of lithium transition metal oxide represented by Formula Li.sub.xM.sub.yN.sub.1-yO.sub.2-A.sub. and a coating layer of lithium transition metal silicate represented by Formula xLi.sub.2O.yNO.sub.a.SiO.sub.2-B.sub.which in-situ formed on the core, wherein 0.8x1.3, 0.6y1.0, 0.01x2.1, 0.2y1.5, 0.1a3.0, 00.2, 00.4, 00.5, 00.5. The positive active material according to the present invention has high capacity, desirable cycling performance and safety performance, as well as desirable thermal stability.

Mixed-metal oxides and lithiated mixed-metal oxides are disclosed that involve compounds according to, respectively, Ni.sub.xMn.sub.yCo.sub.zMe.sub.O.sub. and Li.sub.1+Ni.sub.xMn.sub.yCo.sub.zMe.sub.O.sub.. In these compounds, Me is selected from B, Na, Mg, Al, Si, K, Ca, Sc, Ti, V, Cr, Fe, Cu, Zn, Ga, Ge, Zr, Nb, Mo, Ru, Ag, In, and combinations thereof; 0x1; 0y1; 0z<1; x+y+z>0; 00.5; and x+y+>0. For the mixed-metal oxides, 15. For the lithiated mixed-metal oxides, 0.11.0 and 1.93. The mixed-metal oxides and the lithiated mixed-metal oxides include particles having an average density greater than or equal to 90% of an ideal crystalline density.

This thermoelectric conversion module is formed by electrically connecting, by a conductive member, one end of an n-type thermoelectric conversion element having a negative Seebeck coefficient and having a half-Heusler structure to one end of a p-type thermoelectric conversion element containing an oxide having a positive Seebeck coefficient at a temperature of 25? C. or higher. The conductive member is connected to the n-type thermoelectric conversion element and the p-type thermoelectric conversion element through a connection layer containing a conductive metal comprising silver, and the connection layer is characterized by further containing an oxide to reduce the bond resistance between the n-type thermoelectric conversion element and/or the p-type thermoelectric conversion element.