NOVELTY - The non-aqueous electrolyte secondary batteries e.g. lithium-ion batteries for driving power sources for mobile information terminals e.g. mobile telephones, comprises a positive electrode having a positive electrode active material containing an olivine lithium iron phosphate-based compound, a negative electrode having a negative electrode active material, a separator interposed between the positive and negative electrodes, and a porous layer containing inorganic particles and a binder for the inorganic particles.    USE - The non-aqueous electrolyte secondary batteries such as lithium-ion batteries and polymer batteries are useful for driving power sources for mobile information terminals such as mobile telephones, notebook computers and personal digital assistants.    ADVANTAGE - The non-aqueous electrolyte secondary batteries exhibit high capacity and high reliability even with a high-power battery configuration, and have an excellent cycle and storage performance even when an olivine lithium iron phosphate-based compound is used as a positive electrode active material.    DETAILED DESCRIPTION - The non-aqueous electrolyte secondary batteries e.g. lithium-ion batteries for driving power sources for mobile information terminals e.g. mobile telephones, comprises a positive electrode having a positive electrode active material containing an olivine lithium iron phosphate-based compound, a negative electrode having a negative electrode active material, a separator interposed between the positive and negative electrodes, a porous layer containing inorganic particles and a binder for the inorganic particles, an electrode assembly having the positive and negative electrodes, the porous layer and the separator, and a non-aqueous electrolyte impregnated in the electrode assembly. The porous layer is interposed between the separator and the positive electrode and/or between the separator and the negative electrode in which the porous layer has a thickness of 4 microns or less. A product of separator thickness and porosity is equal to or less than 1100 (microns.%). The inorganic particles have an average particle size greater than the average pore size of the separator. The positive electrode active material contains lithium-transition metal composite oxide, which is having an operating potential nobler than the olivine lithium phosphate-based compound. The lithium-transition metal composite oxide is LiNi1/3Co1/3Mn1/3O2.    DESCRIPTION OF DRAWING(S) - The diagram shows a graph illustrating a relationship between remaining capacities and separator pore volumes after stored in a charged state.