Provided are an electrolyte which may prevent the degradation of the battery performance by including a functional group which can react with a side reaction site which is responsible for decomposition of negative electrode material components and a functional group which can react with moisture which is responsible for decomposition of positive electrode material components in an electrolyte of the battery to ensure the stability of the battery at high temperatures, and a secondary battery manufactured by adding the same. The present invention may employ a compound including a functional group which can react with a side reaction site of a negative electrode material and a functional group which can react with moisture to maximize the improvement of the storage performance of a secondary battery at high temperatures.