TECHNOLOGY FOCUS - ELECTRICAL POWER AND ENERGY - Preferred Battery: The cathode comprises lithium-manganese composite oxide as a cathode active material. The lithium-manganese composite oxide is at least one selected from Li1+aMn2-aO4 (where a is 0 to 0.33), LiMnO3, LiMn2O3, LiMnO2, LiMn2-aMaO2 (where M is Co, Ni, Fe, Cr, Zn, or Ta, and a is 0.01 to 0.1), Li2Mn3MO8 (where M is Fe, Co, Ni, Cu, or Zn), and LiMn2O4 having Li moiety substituted with an alkali earth metal.    TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Components: The TiO2 has a particle size of 1-500 nm. The TiO2 is contained in an amount of 1 to 10 parts by weight based on 100 parts by weight of the anode active material. The anode active material is a carbonaceous material.    TECHNOLOGY FOCUS - POLYMERS - Preferred Components: The styrene-butadiene rubber (SBR) has a transition temperature (Tg) at less than or equal to25degreesC. The styrene-butadiene rubber (SBR) comprises a hydrophilic functional group. The hydrophilic functional group forms a hydrogen bond with the other base materials. The styrene-butadiene rubber (SBR) is a rubber polymerized with a butadiene-containing monomer and a styrene-containing monomer; or a butadiene-containing monomer; a styrene-containing monomer; and at least one hydrophilic functional group-containing monomer selected from maleic acid, acrylic acid, acrylate, carboxylic acid, a nitrile group, a hydroxyl group, an acetate group, a mercapto group, an ether group, an ester group, an amide group, an amine group, and a halogen atom. The styrene-butadiene rubber (SBR) has an average molecular weight of 10000-1000000. EXAMPLE - Graphite (97 parts by weight (pbw)) as an anode active material and titanium oxide (3 pbw) were used, and styrene-butadiene rubber (SBR) was added to an N-methyl-2-pyrrolidone (NMP) solvent to obtain anode slurry. Then, the anode slurry was coated on a copper current collector to prepare an anode. LiMn2O4 was used as a cathode active material, and a conductive material and a binding agent were added to an NMP solvent to obtain cathode slurry. Then, the cathode slurry was coated on an aluminum current collector to prepare a cathode. A solution of ethylene carbonate (EC)/ethylmethyl carbonate (EMC)/diethyl carbonate (DEC) (1:2:1) with 1M of LiPF6 added to it was used as an electrolyte. Between the prepared cathode and anode, polyolefin separator film was disposed. Then, the electrolyte added with an electrolyte additive was introduced to prepare a battery (test). A lithium secondary battery (control) was prepared in a similar manner except that the titanium oxide particles were not used and a polyvinylidene difluoride (PVdF) binder was used instead of a SBR. Storage performance at high temperatures of the test and control lithium secondary batteries was evaluated as follows. The test/control battery was charged with a current of 0.5 C at a voltage of 3-4.2 V. The initial capacity of the battery was measured, and then the capacity before/after storing for three days at 65degreesC was measured in the following method. The values were compared. The capacity of the test/control battery measured by charging to 0.5 C was discharged by 50%, and 10 C was flown through the test/control battery for 10 seconds. Using the voltage drop during the 10 seconds, cell resistivity was measured. Then, the calculation of the capacity was thus carried out. The test/control battery showed 92.1/82.8% capacity preservation after the high-temperature storage.