LITHIUM SECONDARY BATTERY CONTAINING HIGH ENERGY DENSITY POSITIVE ELECTRODE MATERIALS AND AN ORGANIC/INORGANIC COMPOSITE MICROPOROUS SEPARATOR MEMBRANE

摘要

The present invention provides a secondary battery comprising a positive electrode, a negative electrode, a separator membrane, and an electrolyte. The positive electrode contains a mixture of a first positive electrode material defined by the specification of the present invention and one or more second positive electrode materials selected from the group consisting of a first sub-second positive electrode material and a second sub-second positive electrode material defined by the specification of the present invention. Said two positive electrode materials (first positive electrode material : second positive electrode material) are mixed at a mixture ratio of 50:50 to 90:10. The separator membrane is an organic/inorganic composite microporous separator membrane comprising: (a) a polyolefin-based separator membrane base, and (b) an active layer in which one or more areas selected from the group consisting of the surface of the base and a portion of pores of the base are coated with a mixture of particles of inorganic substances and the polymer of a binder. The active layer of the organic/inorganic composite microporous separator membrane is provided with a structure in which particles of inorganic substances are connected and fixed by the polymer of the binder, and in which micropores are formed by the interstitial volume between particles of the inorganic substances.