Why The US Military Chose Silicon-Graphene Batteries

The US military just approved funding for a new silicon-based battery, charging forward into commercialization. But why the push? NanoGraf’s silicon oxide-graphene (SOG) batteries aren’t just an upgrade to lithium—they’re versatile enough for everything from phones and backup storage to EVs. The DOD recently signed a $15 million contract with NanoGraf, bringing its total investment to around $45 million. But these aren’t for advanced vehicles or drones. They’re for STUBs—small tactical universal batteries—like radios and other compact devices.¹² So, why go for high-tech batteries in small gear, and why silicon oxide and graphene? Could this be a compelling next-gen battery for the rest of us?

Military Objectives

We talk about batteries a lot … and for good reason. Today’s lithium batteries are great, but our demand for energy also means we need to find the most energy dense, safe, and affordable way to do that. The challenge is that the new battery technologies on the horizon aren’t going to be very affordable at first, which is why the military sinking a lot of money into NanoGraf’s battery is so interesting. They can absorb those higher, early adopter prices, which we will hopefully be able to benefit from later. But the military’s motivation begs two questions : why use advanced batteries in these small devices, and why invest in silicon oxide and graphene?

The answer to both questions is that batteries are more important than you might think to the military. A modern soldier is expected to carry about 100-plus pounds of equipment in their kit, and up to 20 of those pounds are batteries.³ The exact amount of gear varies based on mission objectives, length and ability to resupply. Still, it seems like a lot of batteries until you realize just how many battery-operated devices soldiers are equipped with. These include radios, GPS systems, laser sight systems, or sometimes a computer. And with this much equipment, you’re probably going to eat through batteries very quickly.³

Typical batteries can be quite heavy, so finding longer lasting batteries would mean soldiers would have to carry less of them. Alternatively, finding lighter batteries is another path toward lightening a soldier’s load.⁴

There’s also some strategic supply factors in play too. China makes over 80% of the world’s lithium-ion batteries and,⁵ for economic and strategic reasons, the Army doesn’t want to rely on China for its battery needs. Finding a battery that isn’t just better, but is made in the US-of-A, is a high priority.⁶

This takes us back to NanoGraf. Their SOG batteries combine the power of a silicon oxide anode with their own proprietary graphene scaffolding, an atomically-thin (and often over-hyped) wonder material. These batteries are supposed to be 15% lighter than their competitors, and also last 15% longer. That 15% might not sound like all that much, but it could make the difference between life and death for someone out in the field.⁴ They claim their battery cell offers up to 20% more range and 50% more playback time than standard lithium ion batteries.⁷ Just like other silicon-based batteries, they charge faster than standard lithium too, by a factor of up to 10.¹

What is a SOG battery? How does it work and where did it come from? To explain all that we have to talk about its forebears: lithium, graphite and silicon

What’s So Special About SOG Batteries?

NanoGraf’s SOG uses a patent-pending graphene scaffolding system to contain and protect silicon nano-particles in the anode.¹ That’s a lot of science but let’s break it down.

First, this is a standard lithium battery. You know it, you love it, and you’re almost definitely watching this video on a device powered by something just like it. Traditionally, these batteries use graphite as their anode, or the electrode that loses electrons.⁸ Graphite is great at this because it’s comparatively cheap, abundant, lightweight and long lived. It also has respectable energy density and power density ratings too.⁹¹⁰ Plus, graphite’s layered structure makes its great at intercalating lithium ions. Essentially, it has a lot of cubby holes that are perfect for storing those ions until we need to discharge them.¹¹ The proof for this is in the pudding: lithium batteries dominate the market and graphite anodes are part of that, but we can go a step further with silicon anodes.

Silicon makes for an impressive anode because it’s crazy-good at storing lithium ions. Just one silicon atom can hold onto four lithium ions. This makes a battery with a silicon anode up to 24 times more efficient and nearly 10 times more energy dense than the already energy dense graphite.¹²

But silicon isn’t perfect either. Storing vast amounts of lithium means that it tends to swell and warp more than a standard lithium battery with a graphite anode. This causes a lot of mechanical stress and can quickly ruin the battery’s capacity, if it doesn’t just destroy it from the inside out.¹³ Silicon anodes also react a bit strangely with electrolytes, forming a solid electrolyte interphase (SEI) layer. Sort of like a scab or a roadblock. Anyway, this layer forms during the battery’s first cycle and blocks the silicon’s surface area, making travel rougher for the lithium ions and reducing the battery’s efficiency.¹⁴ This results in the grimly named “irreversible 1st-cycle loss” problem.⁷

How to prevent this? Well, if you’re NanoGraf, with graphene. This wonder material is made from common graphite, but its crystal structure, or the way graphene’s atoms are arranged, make it very uncommon.¹⁵¹⁶ Graphene’s atoms are arranged in a honeycomb-like structure, and even at just one atom thick its 200 times stronger than steel.¹⁷ Most importantly for our video today, graphene is very lightweight and one the best electrical and heat conductors since copper. Possibly the best conductor we currently know of.¹⁸

You see, electrical conductivity is really just a measure of how freely a material lets electrons flow through it.¹⁹ You can think of materials with poor conductivity kinda of like a winding road with lots of stoplights and potholes. It takes a lot more time and “effort” for the electrons to travel down poor-conductivity-avenue than the open and organized lattice of the graphene highway.

Surface area also makes a difference here. Sticking with the road analogy, if you want to get the most cars-slash-electrons from point A to point B, it helps if there’s a lot of lanes or paths to get there … and they’re all very short. Again, graphene is just an atom thick. This gives it a very large surface area,¹⁵ which means a lot of short, open roads for the electrons. These features, along with its naturally high electrical conductivity, mean that graphene is like a superhighway for electrons.¹⁵²⁰

However, a battery’s job isn’t just to move ions around, we also want to store them. On that front graphene could use a little help. Oh … and, hey, that’s what silicon is good at. Often too good. And that takes us back to NanoGraf. The super thin, super conductive graphene scaffolding protects the silicon oxide particles and improves their robustness.¹ It also helps keep the silicon oxide’s swelling in order, but now you get all those graphene upsides in there too. It’s a win-win, but SOG batteries aren’t without their flaws.⁷

Limitations

What possible limitations could a battery made from a wonder material that’s stronger than steel, more conductive than copper, while being atomically thin possibly have? Well, I’ll give you just one guess: it’s the cost.

Graphene’s been around for 20 years at this point. Its inventors won the Nobel prize for its creation because graphene’s potential is off the charts. However, it hasn’t really lived up to that potential yet because it’s so difficult and labor-intensive to manufacture.²⁰ While you can technically make graphene with scotch tape, doing so isn’t going to yield graphene that is high enough quality for electronics or most other uses. It’s easy to isolate a few graphene flakes, but making commercial quantities of high quality stuff requires complicated and/or expensive techniques. ²¹ This is a serious supply chain bottleneck that can further drive up the cost of final battery product.²²

This has led to a vast array of experimental graphene manufacturing techniques. Some of my favorites include using lasers to flay a thin sheet of graphene from its graphite, or using bacteria to turn graphene oxide into graphene proper. And there’s also bizarre techniques like heating up vegetable oil or using everyday sugars like glucose and fructose to help synthesize the graphene.²³

That all highlights another important point. Naturally occurring graphene wasn’t discovered until 2023.²⁴ For all practical purposes, it has to be manufactured. While graphite is relatively cheap, the labor, time, and techniques that turn it into prized graphene are not. This makes graphene more expensive, and also makes it hard to scale-up. If we can get around the cost and difficulty of making graphene, then that really opens the door to its applications.

Of course, NanoGraf is aware of these issues and is doing their best to solve them. Probably one of reasons why the U.S. Military reached out to them (and others) for their SOG batteries. They’ve developed their manufacturing process with scaling up in mind. Allegedly, NanoGraf’s tech can just be “dropped in” to any pre-existing Silicon Oxide (SiOx) battery production line, and plays well with existing cathodes.⁷ NanoGraf claims that they can use cheaper, easier, conventional battery techniques to fabricate their stuff instead of the typical, costlier silicon manufacturing techniques like vapor deposition.⁷ How exactly this works seems hidden behind the ‘proprietary’ wall for now, which always raises an eyebrow for me. But given that they’re actively producing a large order of batteries for use in radios, there seems to be something tangible backing up these claims.

With these drawbacks in mind, where does NanoGraf’s SOG battery sit on the technology readiness scale? It’s up there but, probably closer to a 7 than an 8.

NanoGraf just began their first large volume production run of M38 18650 cells for the U.S. military, so I think it’s reasonable to assume they’ve passed all the standards and safety checks. Sounds like they’re ‘flight-tested’ and ready to rock, but not in the field just yet. Still, this is an exciting step forward.⁴

Afterall, military tech has a long and storied history of making it into public hands. From canned food to GPS, from epipens to digital cameras, so many everyday items started as cutting-edge military tech. So I’m tentatively hopeful that silicon-graphene batteries will follow a similar path.²⁵

Though, military applications are just one possible road to commercialization. NanoGraf was just recently awarded $60 million dollars from the Department of Energy (DOE) to retrofit “Buick City” in Flint, Michigan into one of the largest silicon battery plants in the world. This plant will focus on EV batteries and will allegedly produce 2,500 tons of silicon-based anodes per year.²⁶The groundbreaking starts next year, so we’ll see if they can live up to that.²⁷ This will be the third facility NanoGraf has opened. They already have a couple facilities in Chicago.²⁸ This kind of expansion is a good (though not bullet-proof) sign that both the manufacturing and economic sides of the business have had the kinks worked out.

Maybe it won’t be too long until your phone or car is powered by one.