LITHIUM SECONDARY BATTERIES CAPABLE OF SELF-POISONING

The invention provides a lithium secondary battery capable of self-poisoning, which includes a positive active material, a negative active material, an electrolyte located between the positive active material and the negative active material to allow lithium ions move therebetween, and a poisonous agent, including an initiating-reaction catalyst and a dopant. The dopant has a phosphorus-oxygen bond, a boron-oxygen bond or a sulfur-oxygen bond exposed at the free end, or a phosphorus-oxygen bond, a boron-oxygen bond or a sulfur-oxygen bond that is not exposed at the free end and is shielded by an organic or inorganic group. When the temperature of the lithium secondary battery reaches a first predetermined temperature, the dopant will react with the initiating-reaction catalyst to release at least one phosphorus-oxygen bond, boron-oxygen bond or sulfur-oxygen bond with free radicals or unsaturated bonds. Therefore, the positive active material of the lithium secondary battery will be contaminated to make the lithium secondary battery harmless.