Medical devices is an obvious potential application for beta decay power. In the past, nuclear power sources were at a major size disadvantage and chemically powered cells can also provide very long service life at such small power draw.
So this definitely isn't nearly as much of a new concept as the media is suggesting. The question is whether they have achieved a compact enough design to be preferential over competing chemically powered cells.
Another application would be cmos batteries for holding memory states. Using ssds in external enclosures is compelling to reduce the amount of time it takes to actually read and write a full drive. But ssds need to be powered every once in a while. If their internal power storage depletes they lose data. Backup ssd drives with an indefinite power source would definitely be a compelling option. I do however doubt if this technology could ever be cheap enough for such an application. The materials used seem rather expensive.
100 microwatt per battery, but the battery itself is tiny, 15x15x5 mm. Average cellphone battery is ~ 30x60x5 mm, so you can fit 8 cell there. Is it enough to power a phone?
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.
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.
The power density is about 0.01125m³ per watt. A high end smartphone (snapdragon 8 gen 3 uses 11w of peak power) with a body size similar to Galaxy s23 ultra, would be almost 10 meters thick.