What would be your application for a battery that never goes flat., page-2

First I a holder, I don’t think there will be a problem making a battery of 3.7v that recharges with humidity ( as forecast by the company). But I see a couple of possible issues mostly in the amount of energy that can be delivered. There is no free lunch, to deliver energy that energy has to be obtained, I’m thinking amp/ hours as opposed to volts, so at least in the earlier stages I think we can discount anything with high energy drain.
But anything else you can think of is another matter entirely. How about wearable body function sensors, heart rate pressure, temperature glucose ect. Personal item trackers that never go flat ( have you had anything stolen) even for pets and stock, remote monitoring for security, environmental, weather, fires ( never change a battery in a fire alarm again or look for new batteries fo your remote) the list could be huge.