Morning all, and welcome back. Last month, I sat down with Baratunde Cola of Carbice and we went deep on the thermal side of carbon nanotubes, vertically aligned forests of tubes acting as assembly joints, nano springs that flex under thermal cycling, the huge Dow partnership. If you missed it, go read Edition #007. It's a good one.
And as exciting as these premium products are, the biggest CNT market by tonnage is batteries. 8 editions in, it really is time to talk about batteries.
Batteries consume roughly 60-65% of all CNTs produced globally. More than polymers, composites, electronics, and thermal management combined. Total CNT demand was around 14,000 tonnes in 2022. By 2030, LG Chem projects that figure hitting 95,000 tonnes, with batteries taking the lion's share. Yet most people, even in the CNT world, think of this as "just sprinkling some tubes in a slurry." It's much more than that.
So today we ask: how important are CNTs to batteries right now, are they about to become more important, and could they become a critical material?
5 Things You'll Learn
Batteries eat most of the world's CNTs. Around 60-65% of all CNTs by volume go into batteries today. By 2030, it could be 75%+. This is where the tonnage goes.
In batteries, it's all about alignment. Vertically aligned CNTs are essential for thermal interfaces. But batteries need tangled, randomly-oriented tubes to create 3D conductive networks. Same material, different physics.
Today, CNTs are an advantage, but not a necessity. You can still build a decent battery with carbon black. But CNTs boost energy density by ~12%, improve cycle life, and enable faster charging.
For next-gen batteries, CNTs become essential. Silicon anodes, solid-state, lithium-sulfur, every emerging chemistry needs CNTs more than current ones do. The dependency is increasing.
The critical material question is coming. CNTs aren't on any government's critical materials list yet. But with ~85% of supply concentrated in Asia and demand set to 5-7x by 2032, the parallel to graphite is getting hard to ignore.
I. Why You Can't Just Stand Them Up
In a thermal interface, CNTs are directional heat conduits. You want every tube pointing the same way, chip to cold plate, point A to point B. The physics is one-dimensional. Phonons travel down the tube axis in a straight line. That's why Carbice grows their tubes vertically.
In a battery electrode, the function is completely different. CNTs are 3D electron bridges. The active materials in a battery, your NMCs, your LFPs, your silicon, your graphite, don't conduct electricity well on their own. You need a conductive network threading through billions of particles, connecting them to the current collector so electrons can flow in and out during charging and discharging. This network needs to reach in every direction. Random orientation actually helps, because you want connection points everywhere, not just along one axis.
Think of it this way. VACNTs are like laying a motorway in a straight line from London to Edinburgh. Battery CNTs are like threading chicken wire through a bag of marbles. You're trying to connect everything to everything.
Battery electrodes are manufactured by mixing a slurry, active material, binder, conductive additive, and solvent all churned together, then coating that slurry onto metal foil and drying it. VACNTs are grown on rigid substrates at 600-1,000°C. You'd have to scrape them off, destroying the alignment, then re-disperse them into the slurry. At that point, they're just expensive random tubes.
It's the same carbon but different geometry, different physics. In thermal, you want aligned tubes as directional heat highways. In batteries, you want tangled tubes as a percolation network.
II. Nice to Have, or Can't Live Without?
Right. So batteries use bulk, randomly-oriented CNTs as conductive additives. But how important are they, really? Could you just use carbon black instead?
Honest answer: today, CNTs are a genuine performance edge, but not yet essential. Most lithium-ion batteries rolling off production lines still use carbon black as their conductive additive. Carbon black works. It's cheap, it's understood, and procurement teams know how to buy it. You can build a perfectly serviceable EV battery without a single nanotube. But the performance gap exists and keeps widening.
Carbon black needs 5-15% of the electrode mass just to create a conductive network. That's 5-15% of space that isn't storing energy. CNTs do the same job at 10-60x lower loadings because their extreme aspect ratio, imagine tubes a thousand times longer than they are wide, creates efficient percolation networks with far less material. Less additive means more room for active material. More active material means higher energy density.
LG Chem has scaled CNT production from 1,700 tonnes per year in mid-2023 to 6,200 tonnes by the end of 2024, and is building towards 10,000+. OCSiAl, the single-wall CNT monopolist (they hold roughly 97% of global SWCNT market share), says their TUBALL products are "widely used in most lithium-ion battery systems." OCSiAl's Chinese manufacturing partners are tripling TUBALL BATT dispersion capacity to 52,000 tonnes per year by end of 2025. You don't build that kind of capacity on a whim.
As battery OEMs push for higher energy density to hit EV range targets, 400 miles is the new minimum for premium models, the performance gap between carbon black and CNTs becomes harder to ignore. CNTs are shifting from "nice optimisation" to "how we hit our customer specs."
III. Every New Chemistry Needs Them More
Silicon Anodes: Essential
Silicon has been the promised land for battery anodes for two decades. It stores ten times more lithium per unit mass than graphite. The problem is that silicon expands by roughly 300% when it absorbs lithium during charging, then contracts again during discharge. This repeated swelling and shrinking literally pulverises the electrode, breaking electrical contact and destroying the cell within a few dozen cycles.
Carbon nanotubes are looking like the best answer. CNTs act as a flexible scaffold, a conductive mesh that wraps around silicon particles and stretches with them during expansion, maintaining electrical contact through the volume changes. Recent research shows SWCNTs deliver 83% higher cycle life than MWCNTs when used with silicon anodes, because the thinner single-wall tubes create more intimate contact with the silicon surface. For high-silicon anodes at scale, there is no commercially viable alternative to carbon nanotubes.
Solid-State Batteries: Significant, Heading to Essential
Solid-state batteries replace the liquid electrolyte with a solid one, eliminating the fire risk and potentially doubling energy density. Toyota is targeting 2027-2028 for first-generation solid-state EVs. In a dry cathode, you still need electron conduction. CNTs create the conductive network within the solid cathode layer. The solid-state battery market is projected to reach $40-50bn by 2035.
Lithium-Sulfur: Essential When It Arrives
Lithium-sulfur offers 3-5x the energy density of current Li-ion, but suffers from polysulfide dissolution. CNTs act as a containment structure, trapping the polysulfides. The dependency is architecturally baked in — if it ever arrives, it can't work without CNTs.
IV. The Supply Chain Nobody's Watching
In 2010, China controlled about 97% of global rare earth production. The West knew this but did nothing, the volumes were small, the materials obscure, and there were always more pressing things to worry about. Then China restricted exports during a diplomatic spat with Japan and the price of neodymium went from $42/kg to $340/kg in under a year.
I see the same pattern forming with carbon nanotubes. Graphite is already a critical material. China restricted graphite exports in October 2023, sending the battery industry scrambling for alternatives.
CNTs aren't there yet. Today, you can swap CNTs for carbon black and accept the performance hit. But when silicon anodes move from niche to mainstream, the carbon black fallback disappears. You genuinely need CNTs. Meanwhile, the supply picture is already ugly. LG Chem (South Korea) and Cnano (China) dominate battery-grade MWCNT production. OCSiAl holds 97% of the SWCNT market. There's basically no US battery-grade CNT production capacity. CHASM Advanced Materials in the US is building a 1,500 tonne reactor, but that's a drop against forecast demand of 50,000-70,000 tonnes.
The tipping point is silicon anodes. When they go mainstream, CNTs stop being a performance additive and start being a structural necessity. That's when the critical material classification becomes inevitable. The question is whether policy catches up before or after a supply disruption.
From Additive to Infrastructure
Carbon nanotubes started as a lab curiosity. They became a performance additive for batteries, nice to have, not essential. But as battery chemistry evolves through silicon anodes, solid-state architectures, and new cathode formulations, CNTs are becoming infrastructure. The conductive skeleton that next-generation batteries literally can't function without.
This is the same trajectory graphite followed a decade ago. First an additive. Then a structural component. Then a critical material with export controls and sovereign anxiety. CNTs are on the same path, just earlier in the curve.
For investors, the window is now. Battery-grade CNT production is about to become a strategic asset. Watch silicon anode adoption rates. That's the trigger that tips CNTs from "nice optimisation" to "supply chain vulnerability."
The boring materials are always the ones that matter most. Nobody writes fun little press releases about conductive additives. But without them, the energy transition doesn't work.
Everybody's worried about lithium supply chains. Almost nobody is watching the 0.1% additive that makes the lithium work.
Thanks, Lawrence x
