Why does news reporting of science and technology have to be so terrible at baseline? I know the answers to this question – lack of expertise, lack of a business model to support dedicated science news infrastructure, the desire for click-bait and sensationalism – but it is still frustrating that this is the case. Social media outlets do allow actual scientists and informed science journalists to set the record straight, but they are also competing with millions of pseudoscientific, ideological, and other outlets far worse than mainstream media. In any case, I’m going to complain about while I try to do my bit to set the record straight.

I wrote about nuclear diamond batteries in 2020. The concept is intriguing but the applications very limited, and cost likely prohibitive for most uses. The idea is that you take a bit of radioactive material and surround it with “diamond like carbon” which serves two purposes. It prevents leaking of radiation to the environment, and it capture the beta decay and converts it into a small amount of electricity. This is not really a battery (a storage of energy) but an energy cell that produces energy, but it would have some battery-like applications.

The first battery based on this concept, capturing the beta decay of a radioactive substance to generate electricity, was in 1913, made by physicist Henty Moseley. So year, despite the headlines about the “first of its kind” whatever, we have had nuclear batteries for over a hundred years. The concept of using diamond like carbon goes back to 2016, with the first prototype created in 2018.

So of course I was disappointed when the recent news reporting on another such prototype declares this is a “world first” without putting it into any context. It is reporting on a new prototype that does have a new feature, but they make it sound like this is the first nuclear battery, when it’s not even the first diamond nuclear battery.  The new prototype is a diamond nuclear battery using Carbon-14 and the beta decay source. They make diamond like carbon out of C-14 and surround it with diamond like carbon made from non-radioactive carbon. C-14 has a half life of 5,700 years, so they claim the battery lasts of over 5,000 years.

The previous prototype nuclear diamond batteries used Nickle 63, including this Chinese prototype from earlier this year, and the one from 2018. So sure, it’s the first prototype using C-14 as the beta decay source. But that is hardly clear from the reporting, nor is there any mentions of other nuclear batteries and previous diamond nuclear batteries.

But worse, the reporting says explicitly this technology could replace the alkaline or lithium ion batteries you currently use in your devices. This will likely never be the case, for a simple reason – these devices have an extremely low energy density and specific energy. The current generated by these small diamond batteries is tiny –  on the order of 10 microwatts per cubic centimeter (called the power density). So you would need a 100 liter volume battery to produce one watt, which is about what a cell phone uses (depending on which features you are using).

But wait, that is for Ni63, which has a half life of 101.2 years. C14 has a half life of 5,700 years, which means it would produce about 56 times less current for 56 time longer per a given mass. This is just math and is unavoidable. So using a C14 battery you would need about 5,600 liters of battery to power a cell phone. They don’t mention that in the reporting.

This does not mean there are no potential applications for such batteries. Right now they are mainly used for deep space probes or satellites – devices that we will never be able to recharge or service and may need only a small amount of energy. Putting cost aside, there are some other applications feasible based on physics. We could recycle C14 from nuclear power plants and make them into diamond batteries. This is a good way to deal with nuclear waste, and it would produce electricity as a bonus. Warehouses of such batteries could be connected to the grid to produce a small amount of steady power. A building that is 100 meters by 100 meters by 20 meters tall, if it was packed with such batteries, could product about 35 Watts of power. Hmmm – probably not worth it.

The low power density is just a deal killer for any widespread or large application. You would have to use very short half-life materials to get the power density up, but then of course the lifespan is much shorter. But still, for some applications, a battery with a half-life of a few years would still be very useful.

Another potential application, however is not as a primary power source but as a source to trickle charge another battery, that has a much higher power density. But again, we have the question – is it worth it? I doubt there are many applications outside NASA that would be considered cost effective. Still, it is an interesting technology with some potential applications, just mostly niche. But reporters cannot help by hype this technology as if you are going to have everlasting cell phone batteries soon.