A lithium-ion secondary battery having a positive electrode capable of occluding and releasing lithium ions, a negative electrode capable of occluding and releasing lithium ions, a separator interposed between the positive electrode and the negative electrode, an electrolytic solution, and a current breaking mechanism that works in response to the rise of the battery's internal pressure, wherein the electrolytic solution is incorporated with an aromatic compound and the positive electrode is incorporated with a carbon dioxide gas generating agent which is represented by the formula AxCO3 or AyHCO3. It is highly responsive to overcharging owing to the current breaking mechanism attached thereto which activates in the early stage of overcharging. Therefore, it exhibits high battery performance as well as high safety in the case of overcharging.