[nknighthb]

I seem to recall seeing my first lithium battery smoke detector back in the 90s. I certainly haven't bought a non-hardwired detector that wasn't one of the 10-year lithium battery type in the past decade. (You'd have to ask my electrician what he just installed in my renovated house, I haven't looked too closely at them yet.)

Haven't given me any problems. Haven't heard about them giving anyone else any problems. You seem to be dismissing something that already has a proven track record. Why is that?