A producing method of a solution that contains lithium, at least one of a niobium complex and a titanium complex, and ammonia, wherein an amount of the ammonia in the solution is 0.3 mass % or less. The solution is suitable for forming a coating layer capable of improving battery characteristics of an active material in a battery.

A producing method of a solution that contains lithium, at least one of a niobium complex and a titanium complex, and ammonia, wherein an amount of the ammonia in the solution is 0.3 mass % or less. The solution is suitable for forming a coating layer capable of improving battery characteristics of an active material in a battery.

A piezoelectric element 1 includes a first electrode 20, a second electrode 40, and a piezoelectric layer 30 provided between the first electrode 20 and the second electrode 40. The piezoelectric layer 30 is composed of a composite oxide having a perovskite-type structure and containing potassium (K), sodium (Na), and niobium (Nb), and has a first peak derived from a (100) plane, a second peak derived from a (010) plane, and a third peak derived from a (001) plane in an X-ray diffraction pattern obtained by θ-2θ measurement.

A composite wafer having an oxide single-crystal film transferred onto a support wafer, the film being a lithium tantalate or lithium niobate film, and the composite wafer being unlikely to have cracking or peeling caused in the lamination interface between the film and the support wafer. More specifically, a method of producing the composite wafer, including steps of: implanting hydrogen atom ions or molecule ions from a surface of the oxide wafer to form an ion-implanted layer inside thereof; subjecting at least one of the surface of the oxide wafer and a surface of the support wafer to surface activation treatment; bonding the surfaces together to obtain a laminate; heat-treating the laminate at 90° C. or higher at which cracking is not caused; and exposing the heat-treated laminate to visible light to split along the ion-implanted layer to obtain the composite wafer.

Provided is a piezoelectric film that has a perovskite structure preferentially oriented to a (100) plane and that comprises a composite oxide represented by the following compositional formula: Pb.sub.a[(Zr.sub.xTi.sub.1-x).sub.1-yNb.sub.y].sub.bO.sub.3 wherein 0<x<1, and 0.10≤y<0.13, in which in a case where a ratio I.sub.(200)/I.sub.(100) of a diffraction peak intensity I.sub.(200) from a perovskite (200) plane with respect to a diffraction peak intensity I.sub.(100) from a perovskite (100) plane, as measured by an X-ray diffraction method, is r, and a/b is q, 0.28r+0.9≤q≤0.32r+0.95, 1.10≤q≤1.25, and r≤1.00 are satisfied.

Provided is a piezoelectric film that has a perovskite structure preferentially oriented to a (100) plane and that comprises a composite oxide represented by the following compositional formula: Pb.sub.a[(Zr.sub.xTi.sub.1-x).sub.1-yNb.sub.y].sub.bO.sub.3 wherein 0<x<1, and 0.10≤y<0.13, in which in a case where a ratio I.sub.(200)/I.sub.(100) of a diffraction peak intensity I.sub.(200) from a perovskite (200) plane with respect to a diffraction peak intensity I.sub.(100) from a perovskite (100) plane, as measured by an X-ray diffraction method, is r, and a/b is q, 0.28r+0.9≤q≤0.32r+0.95, 1.10≤q≤1.25, and r≤1.00 are satisfied.

According to one embodiment, an electrode material is provided. The electrode material includes active material particle containing: a niobium-titanium composite oxide having an average composition in which a molar ratio of niobium to titanium (M.sub.Nb/M.sub.Ti) is greater than 2; and at least one element A selected from the group consisting of potassium, iron and phosphorus. The active material particle contain the element A at a concentration in the range of 100 ppm to 2000 ppm.

According to one embodiment, an electrode material is provided. The electrode material includes active material particle containing: a niobium-titanium composite oxide having an average composition in which a molar ratio of niobium to titanium (M.sub.Nb/M.sub.Ti) is greater than 2; and at least one element A selected from the group consisting of potassium, iron and phosphorus. The active material particle contain the element A at a concentration in the range of 100 ppm to 2000 ppm.

A lead-free lithium doped potassium sodium niobate piezoelectric ceramic material in powdered form and having a single crystalline phase and uses thereof are described. Methods of making the said piezoelectric ceramic material are also described.

A lead-free lithium doped potassium sodium niobate piezoelectric ceramic material in powdered form and having a single crystalline phase and uses thereof are described. Methods of making the said piezoelectric ceramic material are also described.