Five Times an Hour

Back in 2020, NDB wanted you to picture your iPhone. Not charging it. The company's chief strategy officer, Neel Naicker, said a battery the same size would "charge your battery from zero to full, five times an hour", then stretched the timeline out loud, from a day to a week to a month to decades. The claims ran well past phones. NDB promised a cell good for nine years in a handset, a car pack that would run for a century, and a pacemaker ticking for 28,000 years, long after everyone who might ever carry one.

The trick, NDB said, was nuclear waste. Take the radioactive graphite left over from power plants, distil it, turn it into tiny diamonds, and let the decay inside throw off a steady current. A problem nobody wants, reborn as a battery nobody has to charge. The story travelled fast. So did the doubt.

Five years on, there is a granted US patent describing how the thing is meant to work, dated August 2025. There is also a federal fraud case, now settled, over what NDB claimed back then. The physics underneath is real. The open question, as with any battery that promises forever, is how much of the pitch the atoms can actually cash.

NDB Inc. has patented a way to pull usable electricity out of radioactive decay using diamond as the conversion material. The lead inventor, Nima Golsharifi (co-founder and chief executive), put NDB on the map in 2020 with controversial claims we will come back to.

The simple version of the future this points to is a sealed power source that makes its own electricity from the inside and runs until its radioactive core decays away.

Compare the method with something more familiar. A solar cell turns light into current when photons knock electrons loose in a semiconductor. Swap the sunlight for radiation from a decaying isotope, swap the silicon for diamond, and you have the same basic trick running in the dark, indefinitely.

Why diamonds?

Silicon and gallium arsenide, the usual semiconductors, have a narrow bandgap, which caps the voltage you can get and lets the radiation slowly wreck the crystal. Diamond has a very wide bandgap, around 5.5 electronvolts, so it can hold a higher voltage and shrug off radiation that would turn silicon to dust over time. The patent leans hard on the idea that the diamond outlasts the isotope powering it.

The core of the filing is the extraction stack. Radiation enters layers of doped diamond and knocks loose electron-hole pairs, the raw electric charge. A surface treatment at one interface builds a small electric field that helps push those charges out, a mechanism the patent relies on to lift how much gets collected. The charges then cross a Schottky contact, tunnel through a thin insulator, and land on a final end contact that doubles as a reservoir, holding charge and nudging the voltage up.

The real game changer is the insulator in the middle…

By electrically isolating the two contacts, you no longer have to pick one metal that is either efficient or high-voltage. You use an efficient material at one stage and a high-voltage one at the next, and collect the benefit of both.

Wrap the assembly in a diamond shield that traps stray radiation, sinks heat, and in the oxygen-free version resists burning, and you have a self-contained cell that generates power for as long as the atoms inside keep decaying.

Every battery you have owned is running with a countdown. Lithium cells lose capacity with each charge cycle and are mostly finished within a few years. That is fine for a phone you replace anyway. It becomes a real problem the moment the battery sits somewhere you cannot easily reach.

Consider a pacemaker. Running the battery down means another surgery to cut the device out and fit a fresh one. The same logic covers a sensor on the seabed, a tag on a satellite, or a monitor down a borehole. The power runs out long before the job does, and replacing it costs far more than the cell itself.

For a whole class of jobs in bodies, in orbit, and in places people cannot return to, lifespan matters more than capacity, and lifespan is exactly what conventional cells run out of first.

The category is nuclear voltaics, batteries that harvest radioactive decay directly in a semiconductor rather than burning it for heat. Diamond is the fashionable material, and NDB is far from alone in reaching for it.

The closest match is Betavolt, a Beijing company whose BV100 sandwiches a nickel-63 core between diamond semiconductors. It is coin-sized, claims a 50-year life, and puts out about 100 microwatts at 3 volts. That is the same family as NDB's design, and Betavolt is further along, with hardware in hand and a stated push toward mass production.

Then there is the University of Bristol and the UK Atomic Energy Authority, which built the world's first carbon-14 diamond battery in late 2024 and spun the work into a company, Arkenlight. The lab grows its own radioactive diamond and is refreshingly plain that the output is microwatts, not the watts a phone would need. Bristol demonstrated a nickel-63 diamond cell back in 2016, so the pedigree is real.

The incumbent nobody in the diamond crowd can match is City Labs of Miami, founded in 2005, which has actually shipped tritium betavoltaics to defence, aerospace, and medical customers for years, and is now working with cardiac-device maker BIOTRONIK on leadless pacemakers. It does not use diamond, but it does have a product and a regulatory track record.

The slice NDB actually competes in, betavoltaic cells, is tiny. One estimate puts it at US$3.4 million in 2023 rising to US$11.4 million by 2030; another at US$2.07 million growing to US$12.89 million over roughly the same window. Small money, fast growth, real niche.

Widen the lens to "nuclear batteries" and the figures balloon and scatter. One house sizes the market at US$89 billion in 2025; another at US$1.74 billion in 2024. A spread that wide is a signal in itself: the label is being stretched across everything from coin cells to spacecraft generators, and the billions mostly describe radioisotope thermoelectric generators, which hold about two-thirds of the category. Betavoltaics are a rounding error inside that number.

Where does the real demand sit? In micropower for medical implants, secure electronics, space payloads, and remote sensors. Space and aerospace take the largest application share today, while medical implants are the fastest riser. None of that is the consumer electronics story NDB's marketing tells.

That is the tension. NDB's leverage in this market is thin: it has intellectual property but what it lacks is a factory, a shipping product, and a route to customers. Its pitch reaches for phones and electric vehicles, the exact corner of the market that microwatt physics cannot serve. The market is sized as if these cells will end up in everyone's pocket. The physics says they will end up in places you will never see. Which forecast is being sold?

Capital is moving into nuclear batteries. Almost none of it is moving into the diamond-powered consumer dream NDB sells.

The flagship round belongs to Zeno Power, which converts isotope heat into electricity for frontier environments. In May 2025 it raised a US$50 million Series B led by Hanaco Ventures, taking its total to more than US$70 million, on top of over US$60 million in US government contracts. Earlier, the US Air Force backed it with a US$30 million agreement to build a radioisotope-powered satellite. The money is chasing watts for defence and space, using strontium-90 and americium-241, not diamond betavoltaics.

On the medical side, City Labs, the Miami tritium-battery maker, won a Commercialization Readiness Pilot award from the US National Heart, Lung, and Blood Institute and is partnering with BIOTRONIK on leadless pacemakers. That is the clearest path to a real product in this whole field, and it runs through tritium and a regulator, not through consumer hype.

State-scale industrial policy sits behind Betavolt, which has moved its nickel-63 coin cell from pilot toward mass production, with a one-watt version promised. Separately, an OTC-listed shell called Nuclear Diamond Batteries, Inc., a Kronos Advanced Technologies subsidiary chasing the same theme through a unit named AtomiQ, has been reporting notices of allowance on its own filings. It shares almost nothing with the patent's assignee beyond a name, which is exactly why it is worth flagging.

The pattern is clean. The deals that closed cluster around watts for defence and micropower for medicine, both de-risked by government money or a regulatory partner. The one corner of this market that has produced a judgment instead of a product is the consumer forever-battery, which is precisely where this patent aims its pitch.

Start with the gap between the promise and the meter. Betavoltaic cells produce microwatts. The patent quotes eye-catching figures for the raw power of its isotopes, up to thousands of watts per kilogram, but that is the energy of the decay itself, before conversion, and diamond turns only a sliver of a percent of it into electricity. Betavolt's comparable cell lands at 100 microwatts. A smartphone draws several watts. The "power your phone forever" framing is not a small exaggeration, it is off by a factor of tens of thousands.

That framing is also the specific trouble this assignee has already been in. In August 2020, NDB issued a press release claiming its battery had been successfully tested at two major laboratories and that it had signed its first beta customers. The SEC alleged both claims were false, that no such tests or customers existed, and that the company raised over US$1.2 million from 68 investors on the strength of them. In June 2025 NDB and Golsharifi settled without publicly admitting or denying the allegations, with NDB paying a US$200,000 civil penalty and Golsharifi paying US$100,000 and accepting a two-year bar from serving as an officer or director. A granted patent proves the company owns a design. It does not prove the device works, and here the same company has a court record about claiming results it did not have.

Then the harder, slower risks. The patent's safety story is genuinely thoughtful. Embed the isotopes inside the diamond crystal so they cannot be pried out, and dope the diamond with boron-10 so it soaks up stray neutrons and can suppress a chain reaction. The flipside is that the filing openly contemplates fissile isotopes such as plutonium-239 and uranium-235 as fuel options. A sealed cell built to run for a century has to be licensed, tracked, and eventually disposed of, and its own text points to the old worry about plutonium-238 pacemakers being burned in a crematorium.