Saratoga Energy (YC W19), Better Carbon Nanotubes from Carbon Dioxide

Hi HN,

I’m Drew, founder of Saratoga Energy ( We make better carbon nanotubes at one-fifth the price. Carbon nanotubes are a form of nano-scale carbon fibers (5,000X thinner than human hair) with remarkably high strength, electrical conductivity, and thermal conductivity properties. This makes them useful in a variety of commercial applications.

Lithium-ion batteries designed for electric cars already use carbon nanotubes to reduce heat generation during charging and to improve electrical conductivity. This results in faster charging and improved battery life. However, the cost is so high ($300/kg) that battery manufacturers are forced to use the minimal amount, rather the optimal amount.

Our breakthrough in manufacturing cost enables battery manufacturers to use the optimal amount, allowing electric cars to safely recharge in 10 minutes or less. This could give electric cars the boost they need to replace gasoline engines.

The idea to start the company grew from an idea posed to me by my Dad back in 2012 - is there a way to transform carbon dioxide, a greenhouse gas, into something valuable? I thought this would be an exciting challenge because most carbon dioxide technologies at the time were focused on storing it in underground caverns or converting it into commodity chemicals where it would be difficult to profit without substantial government subsidies.

After reading an article about Tesla’s intentions to only source raw materials that were sustainably produced in North America, we settled on developing a low-cost electrochemical process to convert carbon dioxide into graphite. Graphite is an essential energy storage material used in lithium-ion batteries. After deciding on the product, my Dad and I put together a small team of chemical engineers to help with the patents and applications for grants from the Department of Energy and the National Science Foundation.

When we received our funding, we began work with Lawrence Berkeley National Laboratory to construct small batteries to test the material we had made. We noticed that some cells would charge three, or sometimes five times faster than commercial reference materials. So we pulled the cells apart to have a look at the graphite with a high-powered microscope. All of the fast-charging graphite was matted with tiny hairs (I later learned that it sounds cooler if you call them “carbon nanotubes”).

We thought about it for a few days and did some research. We eventually figured out that certain metals we had tested in our production process were likely responsible for the growth of carbon nanotubes. So we isolated those metals to test the theory. It worked!

Now we had a process that could either grow carbon nanotubes or graphite - both at an estimated cost under $5/kg. The difference being that the market price for battery-grade graphite is $10/kg and the market price for battery-grade carbon nanotubes is $300/kg.

If the price of graphite is reduced from $10/kg to $5/kg, electric cars get a bit less expensive and the market expands a bit more. If the price of carbon nanotubes is reduced from $300/kg to $5/kg, electric cars cold potentially charge in about the same amount of time it takes to refill a tank of gas, which could create exponential growth in the electric car market. We discussed this with our grant manager and agreed that it made sense to pivot and scale up the carbon nanotube process - which leaves us here today in W19.

What’s different about our technology is that we produce carbon nanotubes through the electrolysis of molten carbonate salts. The electrochemical reaction produces carbon (nanotubes), oxygen gas, and metal oxides, which are further reacted with carbon dioxide to re-generate the carbonate salt starting material. So the net reaction is the input of energy to drive the conversion of carbon dioxide to carbon nanotubes and oxygen.

Industry has been using chemical vapor deposition to make carbon nanotubes since they were first discovered in 1991. We believe that our platform is better for a few reasons: 1) electrochemistry is tunable and this gives us control over the size and shape of the nanotubes, so they can be custom-tailored for specific battery chemistries and applications outside of energy storage as well; 2) the energy requirement for our manufacturing process is estimated to be 27 kWh/kg, five times less energy intensive than chemical vapor deposition; and 3) our technology represents a value-added use for carbon dioxide, and if powered by electricity from renewable sources, would have a negative carbon footprint.

I think the reason nobody has commercialized this production method yet, or come up with some other high-efficiency process, is because chemical vapor deposition is relatively simple to operate and relatively simple to scale. Billions of dollars worth of chemical vapor deposition infrastructure are already established, and historically, there haven’t been many new market opportunities that would justify investing in new technologies to drive down cost.

Only recently have researchers demonstrated the potential for carbon nanotubes to improve the performance of new applications like advanced energy storage, high-strength carbon fibers and composites, lightweight electrical wiring, and concrete composites for roads that don’t crack. If carbon nanotubes were less expensive, these new applications could be worth billions while also creating sizable reductions in greenhouse gas emissions. It is our mission to bring new markets like these to life and to develop new products that best take advantage of what our carbon nanotubes have to offer.

I believe that we are best positioned to break this cost-curve and bring this technology to market because molten carbonate electrochemistry is not a well-known science. What we’ve learned since our foundation in 2012 is not commonly taught in universities. Our knowledge was acquired through hands-on experience and in-house development of intellectual property.

Hopefully some of you folks are also interested in carbon nanotubes, or at least share a mutual dislike for carbon dioxide. I’m looking forward to sharing some ideas with everyone!


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andrey azimov by Andrey Azimov