TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Composition: The nonstoichiometric titanium compound contains lithium-titanium-niobium oxide of formula: Li4+xTi5-x-yNbyO12.y=greater than 0 and less than 0.2.Preferred Process: The carbon composite is alternately obtained by subjecting nonstoichiometric titanium compound containing lithium-titanium-niobium oxide (II) as a carbon source to carbon conjugation process using 4C or more dicarboxylic acid. The nonstoichiometric titanium compound containing lithium-titanium-niobium oxide (II) is manufactured by adding predetermined amount of 4C or more dicarboxylic acid, lithium salt and titanium alkoxide in water, spray-drying solution using spray dryer to obtain precursor, and baking the precursor at 800-900 degrees C for predetermined time in furnace at reducing environment or inert atmosphere, or adding predetermined amount of oxalic acid, lithium salt, titanium alkoxide and niobium alkoxide in water, spray-drying solution using spray dryer to obtain precursor and baking the precursor at 600-900 degrees C for predetermined time in furnace, or adding predetermined amount of 4C or more dicarboxylic acid, lithium salt, titanium alkoxide and niobium alkoxide in water, spray-drying solution using spray dryer to obtain precursor, and baking the precursor at 800-900 degrees C for predetermined time in furnace at reducing environment or inert atmosphere. Preferred Composition: The negative electrode active material contains nonstoichiometric titanium compound comprising lithium-titanium-niobium oxide (II). The negative electrode active material layer contains negative electrode active material comprising nonstoichiometric titanium compound of lithium-titanium-niobium oxide (II). The positive electrode active material layer contains spinel-type lithium-manganese oxide, spinel-type lithium-manganese-nickel oxide (LiMn1.5Ni0.5O4), lithium-cobalt oxide, lithium-nickel oxide, lithium-nickel-cobalt-manganese oxide (LiNi1/3Mn1/3Co1/3O2) and/or lithium iron phosphate.