Toray Industries, Inc.

Mayumi Hara

Shinya Adachi

Eiichiro Tamaki

Hiroaki Kawamura

Yasuo Kubota

Masayuki Kidai

Tomonori Kawakami

Hanxiao Yang

A conventional positive electrode material for lithium ion batteries that is made of positive electrode active material/graphene composite particles has low graphene material ion conductivity and is incapable of providing favorable battery performance. In the present invention, positive electrode active material/graphene composite particles are conferred with high electron conductivity and ion conductivity by formation of an appropriately functionalized graphene/positive electrode active material composite, and are capable of yielding a high-capacity/high-output lithium ion secondary battery when used as a positive electrode active material for a lithium ion battery.

Positive electrode active material/graphene composite particles, positive electrode material for lithium ion cell, and method for manufacturing positive electrode active material/graphene composite particles

Disclosed is a method for producing a polymer electrolyte membrane, which comprises the steps of: removing a part of a salt component produced during polycondensation from a polymerization solution of a polymer electrolyte having a density of an ionic group of 2 mmol/g or more directly by centrifugal separation, thereby preparing a coating solution; applying the coating solution on a substrate by casting; removing a part of a solvent from the coating solution to form a film-shaped material on the substrate; and bringing the film-shaped material on the substrate into contact with water and/or an aqueous acidic solution to remove the salt component produced during the polycondensation. According to the method for producing an electrolyte membrane, even an electrolyte having a high density of an ionic group can be purified. Also disclosed is an electrolyte membrane capable of being used in a fuel cell which is operated at a high temperature higher than 80&#xb0; C. and under low humidity conditions having a relative humidity of 60% or less.

Process for producing polymeric electrolyte membrane

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Okazaki, Japan

Mayumi Hara