Yoshinori Toyoguchi

Positive electrode for non-aqueous electrolyte lithium secondary battery and method of manufacturing the same

A positive electrode for a non-aqueous electrolyte lithium secondary battery comprises an active material represented by the formula Lix A1-y My O2 (wherein A represents at least one transition element selected from the group consisting of Mn, Co, and Ni, M represents at least one element selected from the group consisting of B, Mg, Ca, Sr, Ba, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Al, In, Nb, Mo, W, Y, and Rh, and wherein 0.05≦x≦1.1, and 0≦y≦0.5), a binder, a conductive agent and a current collector. The binder is selected from the group consisting of a copolymer comprising a tetrafluoroethylene unit and a hexafluoropropylene unit, a copolymer comprising a vinylidene fluoride unit, a copolymer comprising a propylene unit and a tetrafluoroethylene unit, and a polymer comprising a trifluoropropylmethylsiloxane unit.

Study on CxN and CxS with disordered carbon structure as the anode materials for secondary lithium batteries

Abstract C x N ( x = 12.5 and 7.3) and C x S ( x = 31.8 and 28.0) with disordered carbon structure was synthesized by chemical vapor deposition (CVD) from pyridine and thiophene, respectively, at 800 °C in the absence or presence of chlorine. Lithium was reversibly inserted into these materials. In addition, C x N and C x S had larger capacities than pyrolytic carbon synthesized by CVD from benzene at 800 °C. The capacities of C x N and C x S increased with increase in nitrogen or sulfur content. In particular, C 7.3 N had a first cycle discharge capacity of 507 mAh/g in the potential range of 0–3 V versus Li/Li + , which exceeds the theoretical capacity of graphite (372 mAh/g). C 28.0 S had a large first cycle discharge capacity of 551 mAh/g. The average interlayer spacing of C 7.3 N increased during charging and decreased during discharging like that of pyrolytic carbon. On the other hand, the average interlayer spacing of C 28.0 S hardly changed during charging and discharging.

Button-type lithium battery using copper oxide as a cathode

Abstract A button-type lithium battery with a nominal voltage of 1.5 V was studied by employing CuO with improved performance as a cathode. The effects of several additives to CuO were examined and the results revealed that CuO heated with a small quantity of Li2CO3 at high temperatures could be used as an excellent cathode material. The operating voltage, utilization of CuO and shelf-life of the lithium—copper oxide battery have been improved with the use of the Li-doped CuO.

Method for producing hydrogen storage alloy particles and sealed-type nickel-metal hydride storage battery using the same

A method for manufacturing hydrogen storage alloy particles comprises steps of obtaining a melt of the hydrogen storage alloy and pulverizing the hydrogen storage alloy by water atomizing process, whereby the melt is pulverized by contacting or colliding with high-speed jetting thereto to be dispersed in the form of solidified fine particles. By employing an aqueous solution of hypophosphorous acid or an alkali aqueous solution in place of water during the water atomizing process, or by etching the oxide films once formed on the surface of the hydrogen storage alloy particles with an aqueous solution of a strong acid, the thickness of the oxide film can be made thinner, and thus a high discharge capacity of a battery configured with a negative electrode comprising the alloy particles can be realized.

Progress in materials applications for new-generation secondary batteries

The status of research and development on advanced batteries in Japan is reviewed. The three types of batteries attracting the most interest are: (1) nickel-metal hydride batteries, (2) secondary lithium batteries, and (3) secondary batteries using solid electrolytes. The advances made in the development of these batteries are described from the viewpoint of the application of new materials. The materials used for batteries come from multidisciplinary research. Hydrogen-storage alloys and conducting polymers are examples of materials with interdisciplinary origins. >

Non-aqueous electrolyte secondary battery and method for producing anode therefor

A non-aqueous electrolyte secondary battery is disclosed which has an anode comprising a carbon material. The carbon material contains at least one of 7-35 wt % sulfur, 6.5-25 wt % oxygen and 10.5-18.3 wt % nitrogen, provided that if the carbon material contains at least two of these elements, the total amount of the elements does not exceed 35 wt %.

Surface Structure and Electrochemical Characteristics of Ti-V-Cr BCC-Type Solid Solution Alloys Sintered with NI

Ti-V-Cr bcc-type solid solution alloys can absorb a large amount of hydrogen and be applied to active materials of the negative electrode in Ni-MH batteries. However, because of the insolubility of Ni into these alloys, the electrochemical characteristics like discharge capacity and cycle life were poor. In order to increase the discharge capacity of hydrogen absorbing alloy electrodes, Ti-V-Cr bcc-type alloy powders were sintered with Ni in order to form Ni contained surface layer on the alloy surface. As sintering temperature rose up, the surface composition changed from TiNi to Ti{sub 2}Ni. TiNi surface layer showed better electrochemical characteristics. For the Ni adding method, Ni electroless plating was preferred because of good adhesion. As a result of optimized conditions, a discharge capacity of 570 mAh/g and an improvement of cycle life were achieved.