Nano Diamond Self Charging Batteries

In recent times, as the spectre of climate change looms ever larger, the search for clean, sustainable and renewable energy sources has become more urgent. Advances have been made in this direction, but it often seems that the technology isn’t moving quickly enough.

So when a company announces that they are planning to produce a self-charging battery that could last for at least ten years, but potentially up to 28,000 years, people tend to take notice. A product like this could revolutionise the energy industry and improve our lives in numerous ways.

At the end of August 2020, this is precisely what happened; NDB Inc. revealed that they had successfully tested such a battery (Nano Diamond Self Charging Batteries) and that it would be commercially available within the next two years. In addition to their bold claims, this California-based ‘green’ start-up company stated that the battery would be manufactured using recycled nuclear waste. And the secret behind their remarkable innovation? Nano diamonds.

A self-charging battery that lasts for well over a lifetime, and which solves the problem of storing spent carbon-14 from nuclear power stations. What could be better? Before becoming too excited, it makes sense to examine the claims more closely and look into the technology involved.

What are nanodiamonds?

Back in 1963, Russian scientists found that diamond nanoparticles were created during nuclear explosions when carbon-based trigger explosives were employed. These tiny particles are no more than 1 micrometre in size [1] and have a unique structure of only a few hundred atoms that has made them useful in a wide range of fields, including medicine, quantum engineering and electronics.

As well as being formed through explosions, nanodiamond synthesis also occurs in a number of other ways:

• Ultrasound
• Hydrothermal
• Ion bombardment
• Laser bombardment
• Electrochemical
• Microwave Plasma Chemical Vapour Deposition (MPCVD)

Of these techniques, explosions (or detonation synthesis) are considered the standard procedure for commercial production as it is relatively simple and produces a large number of nano diamonds.

The process is still quite complex, however, requiring immense pressure and heat. Temperatures in excess of 3000K and pressures of more than GPa are frequently used. The resulting matter has to be rapidly cooled using liquid or gas-based coolants. The process also produces graphitic carbon forms that have to be cleaned from the mixture using processes such as nitric acid oxidation or gaseous ozone treatment [2].

Nanodiamond technology

The potential uses of nano diamonds are only fairly recently being realized. Here are a few of the applications that have benefited from their use:

Engine Oils

In their final form, diamond nanoparticles display the same chemical stability and hardness as their full-scale counterparts. This ‘micro-abrasive’ quality makes them ideal for polishes and engine oils as it aids lubrication [3].

Medicine

The applications here are almost limitless and are still being discovered. Suffice to say, surgery, drug delivery, blood testing and a whole range of medical procedures stand to benefit from replacing the standard nanomaterials with diamond nanoparticles. This is largely due to their unique qualities; they are inert, extremely hard, and they are considered non-toxic to human cells [4].

Another important factor is fluorescence. Fluorescent nanodiamonds (FNDs), made by the process of irradiation with helium ions, are proving indispensable to medical imaging procedures, as the particles exhibit near-perfect qualities (photostability is recorded as ‘infinite’ [5])

Cosmetics

Nano diamonds can be easily absorbed into human skin. They are also highly absorbent and will soak up water along with any skincare product into which they are mixed. When applied to the skin they penetrate deeply, taking the mixture with them, where they help to moisturise and increase the beneficial effects of the lotion.

Electronics

Diamond nanoparticles possess a natural defect known as nitrogen-vacancy centres. This defect can be manipulated to measure fluctuations in the magnetic field as well as to use infrared or green light to control light transmission. Such qualities make them ideal for optical computing, quantum computing, and nanomechanical sensors.

So, how does this apply to self-charging batteries?

Firstly, NDB (which stands for Nano Diamond Battery) take high-grade nuclear waste graphite and process it to make it safe. This graphite is rich in carbon-14 and the purifying process creates masses of extremely small diamonds. As carbon-14 starts to beta decay it turns to nitrogen, which then releases an antineutrino and an electron. The structure of the diamond collects the charge, behaving like a semiconductor and a heat sink, by sending the charge outwards. NDB discovered (aided in no small part by previous research at Bristol University in 2016) that by covering this with a larger, non-radioactive carbon-12 diamond, you can create a virtually indestructible unit that contains the charge as well as any radiation.

In order to produce a battery, several layers of these diamond ‘units’ are stacked and embedded in a circuit board, along with a supercapacitor.

The end result is a small energy generator that has a potential life span of hundreds or even thousands of years – at least well beyond the life expectancy of the unit in which it will be used.

The possibilities here seem endless. The company’s own website lists potential areas of use:

• Automotive – imagine, an electronic vehicle that never requires charging. Transport would be changed forever.
• Aerospace – electric-powered planes would slash environmental pollution from jet exhausts. Drones, satellites, space stations and space rovers would all benefit.
• Consumer electronics – think of all the items you own that run on batteries, and the inconvenience of having to charge or replace them.
• Medical technology – pacemakers, hearing aids and any mechanical implant device could be run without the fear of losing power.
• Industrial – increasing effectiveness of uninterrupted power supplies and enabling businesses to operate in remote locations.
• Defence – ideal for surveillance and essential defence electronics.

At present, the company is seeking investors and tests are being undertaken by beta customers. Until we know more, it’s difficult to say whether this invention will deliver on its promise. But we can always hope.

References

[1] Chung, P.-H.; Perevedentseva, E.; Cheng, C.-L. (2007). “The particle size-dependent photoluminescence of nanodiamonds”. Surface Science.

[2] Holt, Katherine B. (2007). “Diamond at the nanoscale: Applications of diamond nanoparticles from cellular biomarkers to quantum computing”. Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences.

[3] Feinberg, Ashley (April 9, 2014). “How These Microscopic Diamonds Are Going to Shape the Future”

[4] Schrand, Amanda M.; Huang, Houjin; Carlson, Cataleya; Schlager, John J.; Ōsawa, Eiji; Hussain, Saber M.; Dai, Liming (2007). “Are Diamond Nanoparticles Cytotoxic?”. The Journal of Physical Chemistry B

[5] Reineck, P.; Francis, A.; Orth, A.; Lau, D. W. M.; Nixon‐Luke, R. D. V.; Rastogi, I. D.; Razali, W. A. W.; Cordina, N. M.; Parker, L. M.; Sreenivasan, V. K. A. Brightness and photostability of emerging red and near‐IR fluorescent nanomaterials for bioimaging. Advanced Optical Materials 2016, 4, 1549-1557