Abstract: To provide a binder for a storage battery device, whereby good adhesion in an electrode and flexibility are obtainable, and it is possible to realize good charge and discharge characteristics when used for a secondary battery. A binder for a storage battery device, which is made of a fluorinated copolymer comprising structural units (a) derived from tetrafluoroethylene and structural units (b) derived from propylene, wherein the molar ratio (a)/(b) is from 40/60 to 50/50, and the total of the structural units (a) and (b) is at least 90 mol % in all structural units.

Abstract: Disclosed is a negative electrode active material for a lithium ion secondary battery, which is capable of further improving the charge/discharge cycle characteristics. Also disclosed is a lithium ion secondary battery which uses the negative electrode active material for a lithium ion secondary battery. The negative electrode active material for a lithium ion secondary battery is composed of composite particles each of which has a core/shell structure configured of a core part that is formed from a polymer and a shell part that is formed of a metal layer. The metal layer of the shell part is formed by metal plating. Preferably, the metal layer comprises at least a metal layer (a1) that is formed by electroless plating and a metal layer (a2) that is formed by electrolytic plating, in this order from the core part side.

Abstract: Fuel cell membrane electrode assemblies and fuel cell polymer electrolyte membranes are provided comprising manganese oxides which demonstrate increased durability. Methods of making same are provided.