Yoshinori Takada

Material for lithium battery positive electrode and production thereof

The material for a lithium battery positive electrode of the present invention is characterized in that a powder of an active material comprising at least one member selected from the group consisting of lithium phosphates, lithium-cobalt phosphates, cobalt oxides and lithium-cobalt oxides, wherein lithium, cobalt and phosphorus are contained in a proportion of more than 0.1 mole of cobalt and more than 0.2 mole of phosphorus both per mole of lithium, is formed into a sheet using a binder comprising an organic polymer, and the present invention affords a material for a lithium battery positive electrode, which is superior in practical use and production efficiency, without impairing the high electromotive force of the novel active material having the aforementioned composition. The production method of the present invention is characterized by extending a binder solution comprising a powder of the above-mentioned active material on a long support sheet, and drying, and affords a long material for a lithium battery positive electrode stably and efficiently by a continuous process.

Preparation of Superconducting Oxide Films by Sol-Gel Method

For preparing superconducting wires and tapes, the sol-gel method is one of the most useful techniques. We prepared highly-oriented Y-Ba-Cu-O and Bi-Sr-Ca-Cu-O superconducting films using a solution of acetate and propionic acid. The Y-Ba-Cu-O films on Ag substrate were dense and homogeneous and achieved Tc of 88K and J c of 7,500A/cm2 (77K, 0T). The Bi-Sr-Ca-Cu-O films were prepared on MgO substrate. The film including some high-Tc phase and Tc=87K was obtained with the starting composition of 2223.