According to this article, an average smartphone uses 2W when in use. That number will largely be dependent on the screen and SOC, which can be turned off or be placed in a lower power state when the phone isn’t actively being used. (The 5W - 20W figure is for charging a phone.)

With 8 of these cells, you’ll have 800μW, or 0.0008W, and you need 2W. You will need to add a few more batteries… About 19,992 more. If 8 of these batteries are about the same size as a regular smartphone battery, you will need the equivalent of 2,500 smartphone batteries to power just one phone.

Too bad they don’t say how much the new batteries weigh! It would have been fun to see…

If we ballpark it and assume something the size of a regular smartphone battery is 50g (1.7 oz), then our stack of 20,000 of these new batteries could be about 125kg (275 lbs).

I won’t be replacing any of my batteries just yet.

0.8 watts? Honestly, I think it gets closer than I was expecting. (edit: millli/micro, messed it up. This is a tiny amount of power. Needs to get near that 1W they are aiming for to be useful). Searching around, I see estimates of 5-20 watts when fast charging, and 1-2W in standby mode. The article says they are aiming for 1W in the next couple of years, which can probably do it. However, it’s not clear what peak output it. You would probably use half the space for a normal battery and half for this power source, so that the phone can charge itself but also have a higher output when it’s needed.

It probably doesn’t even need to provide all the power. Imagine if your phone would trickle charge wherever you were. If you’re watching netflix you might run out of battery and have to charge. If you aren’t using it much, even if the output of these things can’t keep up, the battery could last days or a week on a charge before eventually running out.

800 microWatts is still about 4 orders of magnitude short of a running a smartphone.

A cell phone uses between 5 watts and 20 watts, according to google, so probably not currently.