Provided is a non-aqueous lithium secondary battery comprising an electrode assembly composed of a cathode, an anode, and a separator interposed between the cathode and anode, wherein the cathode and anode have an electrode material containing an active material applied on a current collector, a non-aqueous electrolyte containing a lithium salt, hydrophobic inactive-particles (also, referred to as “hydrophobic particles”) included in the electrode material, and a battery case sealing all the constituent components. Upon adding hydrophobic inactive-particles to the electrode material in a non-aqueous lithium secondary battery, absorption and inflow of water into the electrode material during the battery production is effectively inhibited such as to prevent side reactions caused by water inside the battery, thereby exhibiting improvement in the high-temperature storage characteristics of the battery.