Nano-diamond self-charging batteries could disrupt energy as we know it | Hacker News Reader

Nano-diamond self-charging batteries could disrupt energy as we know it

newatlas.com

38 pointsyurisagalov20 comments

This is silly. It's not going to disrupt Li-ion. Power outputs are way too low. C14 has a half life of 5700 years. This isn't going to output Li-ion levels of power/weight for 5 millennia. It looks like it might give you microwatts/gram, but this is much closer to existing nuclear tech like RTGs or beta voltaics than it is to Li-ion batteries.

what has half life to be with energy density?

The half life tells you how fast you're using up your fuel. A long half life means you're using the nuclear potential energy in your "battery" very slowly.

Yeah, the way they're presenting it is silly. C-14 decays to N-14 with a mass defect of 156.5 keV/c^2. With a half life of 5730 years, 1 kg of carbon-14 will produce 1.6×10¹⁴ decay events per second. That's 3.8 W/kg specific power, which is roughly 1% of lithium ion -- assuming 100% conversion efficiency.

HOWEVER, we know that only 31% of the decay energy is actually carried away by the beta particles, and the rest ends up as heat (which is not captured)[1]. On top of that, the efficiency of converting the beta particle's kinetic energy into electrical power is low. I found a paper citing a 26% conversion efficiency [2], which seems high but lets go with it. Finally, the mass of the battery obviously includes more than just the C-14. Lets assume that half the mass of the battery is C-14.

That would bring us down to 300 microwatts per gram of C-14, and less than 0.05% of the specific power of a LiIon battery.

[1] There's also a positron that shares half of this energy -- I don't know if these devices capture that, so I'm just leaving it in.

[2] https://www.sciencedirect.com/science/article/pii/S016890022...)

Lotsa claims, artist's rendition of possible product. Wake me up when it's on Amazon.

> NDB says [the batteries] will be cost-competitive with, and sometimes significantly less expensive than – current lithium batteries. That equation is helped along by the fact that some of the suppliers of the original nuclear waste will pay NDB to take it off their hands.

How much C-14 is produce annually?

Unexpectedly, snopes [1] has a good overview of the technology until 2017.

https://www.snopes.com/fact-check/radioactive-diamond-batter...

From this article, it is 15 joules per gm of energy. That means 0.5kwh is generated for 100kg of these cells - typical battery weight in EVs.

But this is continuous process. So in 24hrs, you would get 12kwh which can be stored in super capacitors.

Assuming 10kms per kwh of EV range, this would be 120kms per day.

And if we allocate more kgs for battery, the range would increase.

12kwh a day? Then you could feasibly power a house with these things.

Re-read that snopes article again; 15 joules/gram per day. That means in 24 hours, you only get 0.5kwh from your 100kg battery.

I'm not knowledgeable enough to comment on the validity of these claims but my gut feeling is along the lines of "If it sounds too good to be true..."

Also, the description of the technology sounds so simple that I find it difficult to believe no-one's thought of it before ergo there must be a catch.

It would be great if this was for real though. The possibilities of such such a thing are almost unimaginable.

So is this basically a charge based version of a RTG (hence the diamond semiconductor)?

Edit: apparently these devices are called betavoltaics

High energy electrons make their own current, no heat needed. But if you put it in a phone, the phone will be permanently warm.

Betting these will end up in pacemakers & telemetry only, but not for any legitimate reason.

Looks like betavoltaics in general have super low specific power

I know this isn't necessarily a logic-based conclusion...

My first thought was "Chief Medical Officer? Huh? No. Thanks. I smell bs."

Like many of the comments in the article said, I don't think this would be safe. Diamonds can be shattered and they do burn.

> they do burn

Yikes, I had caught the shattering risk and decided I'd pass on something built literally like the article said. But if these can burn... that takes it to "that externality needs to be fully mitigated before this is made widely available".

The ignition point of diamond is in the range of 700-800 °C in a pure oxygen atmosphere.

In spite of all the grandiose claims, if their claims are even half of what they say, it would be pretty impressive!

I'd love to believe it. It sounds plausible. I'd have to see a lot more to invest in it.

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