Provided is a battery electrolyte comprising an electrolyte salt, an electrolyte solvent and a compound producing chemical reaction products with the exception of water through a chemical reaction with an acid (H.sup.+), and a secondary battery comprising the same. The battery electrolyte according to the present invention can achieve improved high-temperature storage characteristics and the life characteristics of the battery, by using a compound decreasing a concentration of HX (X=F, Cl, Br or I) through a chemical reaction with HX (X=F, Cl, Br or I) which is present in the battery and therefore causes deterioration of the battery performance.