It’d be very interesting to think of an hybrid system in which the betavoltaic cells are coupled with lithium batteries to give them some kind of natural regeneration over time(, a phone or computer could recover go from (50, or 20, or )0 to 100% overnight/‘when it’s not used’)

This current model only gives 8.64 joules per day, but that’s because 86400 is the number of seconds in a day, so if i divide 8.64 per 86400 i obtain 10^-4 W(, P=E/Δt), and the official/rounded number is 100μW.
Its volume is 1125mm^3 (15*15*5mm)

So, to drive 100km in an hour(, without the need to take into account accelerations for now), we’d need 100*200W=20kWh, or 2.10^4 Wh.
Most electric cars would only enable 4 hours at this rate with an 80kWh battery, but since this nuclear “battery” needs to be able to deliver 24h a day, we’d need 24 * 2.10^4 = 4,8.10^5 Wh

Hence, if we need 4,8.10^5 Wh and we have 100.10^-6 Wh for 1,125.10^3 mm^3 , a rule of three would give us 4,8.10^5 * 1,125.10^3 / 100.10^-6 mm^3 , that’s 5,4.10^12 mm^3 , which is indeed 5400m^3 and not realistic.

Even a 200Wh computer would still need 54m^3 , and a 10Wh phone would need 2,7m^3 , the size of a car.

If the output was mutliplied by a thousand(, 100mW instead of 100μW,) then it’d be 2,7dm^3 , the size of a bottle and still a bit too big for a phone, but a “free” energy for 50 years, and if i’m keeping the thought above of an hybridation as a self-regenerative battery it’d refill 240Wh every day(, 24*10Wh,) but that’s only if the output was multiplied by a thousand, which is unlikely.

Thank you very much for the correction, i didn’t know that.

I wonder if i haven’t made a mistake somewhere though, does it make sense that i’m obtaining 100μW by using seconds, and then comparing it with Wh ? If i had to multiply by 3600 before making this rule of three then that would change the conclusion.
8,64J/day would give 0,36J/h = 0,36Wh ? And would also give 100μJ/s = 100μW ?
I.d.k. anymore, but if i’m right this time then we’d need a 75cL bottle to refill 240Wh every day(, and for electric cars only 75L to refill 24kWh). I wouldn’t be surprised if i made mistakes elsewhere so tell me what you think.

Oh yeah, i wouldn’t advise anyone to take this breakthrough as a promise for the future(, as someone who used to read futurism.com i’m well aware of that).

But i could counter your objections if you’re interested :

• it can already be done currently : David Hahn built a nuclear reactor with the radioactive material extracted from clock hands. The nickel-63 is already present elsewhere(, armour plating, boat propeller shafts, …), as well as many other radioactive materials ;
• but it’s probably not feasible : A stronger argument is that the radioactive material is composed of a layer only 2µm thick, in between two layers of diamond, i don’t know enough about the subject to confirm or deny that such extraction would be too difficult/expensive ;
• and even if it were other materials would be a better choice : Finally, at first sight and in my ignorant opinion, i don’t think it’d add much to a bomb, it seems like it’d only infect people in the vicinity, and is only described in the first scenario here(, see the article titled “Terrorism: Nuclear and Biological Terrorism”), which considers it more useful for polluting water reserves for instance, contrary to ^137 Ce, ^131 I, ^32 P, or ^67 Ga. It’d be cheaper/easier and possibly more effective to steal such materials from hospitals rather than extracting it from batteries.

You’d probably have to drill through more than a few of them to have enough radioactivity leaking, at this point the number of people dying because of their stress testing would probably be equivalent to those dying because of chemical batteries explosion. It’d be up to the authorities to estimate the risks correctly and, as you said, we’ll see how much a battery made to last 50 years will cost.