Are lithium batteries safe in smoke detectors?

What a strange question! Perhaps you are worried because you have heard of cell phones and notepad computers catching fire because the lithium ion batteries overheated. Well, a lithium battery is not the same as a lithium ion battery. Lithium ion batteries are rechargeable, and lithium batteries are not. Lithium ion batteries tend to overheat, lithium batteries don't. Lithium ion batteries are made to fit certain instruments, and lithium batteries are made in standardized sizes.

Lithium batteries last a very long time, up to fifteen years, so they are excellent for light loads such as alarms, emergency flashlights, and so on. And they are very safe.