To improve a utilization factor of an active material in a positive electrode so as to provide a secondary battery having high capacity by including a conductive agent, which is formed by including a predetermined quantity of expanded graphite or crushed material of the compression molding of the expanded graphite, in a positive electrode of a non-aqueous electrolyte secondary battery using lithium included composite oxide for positive electrode active material.
A non-aqueous electrolyte secondary battery is formed of a positive electrode, in which lithium-containing manganese composite oxide is used as an active material and in which conductive agent, and binder agent are included and conductive polymer is included at need, an electrolyte layer of high molecular solid, which includes the non-aqueous electrolyte, and a negative electrode, which can store and release lithium. At this stage, as a conductive agent to be included in the positive electrode, crushed material of expanded graphite at 5wt.% or less is used. As the expanded graphite crushed material, an expanded graphite crushed material having mean particle diameter of 1-30μm, specific surface area of 10m2/g or more and true density of 2.00g/cm3 is desirable from the view point of dispersebility, film-forming and adhesiveness, and an expanded graphite crushed material having a crystal layer interval of d002 of 0.337nm or less and crystallite size in the c-axis direction Lc of 10nm or more is desirable from viewpoint of conductivity.
YANAI MASAHIRO
HAYASHI YOSHITAKA
