Graphene and carbon nanotubes are the two most prominent members of the carbon nanomaterial family. Both are built entirely from carbon atoms arranged in hexagonal lattices. Both exhibit extraordinary electrical, thermal, and mechanical properties. Both have been the subject of decades of research, billions of dollars in investment, and enormous commercial expectations.
Yet they are fundamentally different materials — different in structure, different in production, different in how they are used, and different in where they have found commercial traction. Treating them as interchangeable, or as direct competitors, misses the reality of how each material fits into the applications landscape.
Structural Differences
The simplest way to understand the relationship: graphene is a flat sheet, and a carbon nanotube is a rolled-up sheet.
Graphene is a two-dimensional material — a single layer of carbon atoms arranged in a honeycomb lattice, extending in the x and y directions with essentially zero thickness in the z direction (0.34 nm). It is planar, with all carbon atoms exposed on both surfaces.
Carbon nanotubes (CNTs) are one-dimensional structures — the same hexagonal carbon lattice, but rolled into a seamless cylinder. Single-walled carbon nanotubes (SWCNTs) are one layer thick with diameters typically between 0.4 and 2 nm. Multi-walled carbon nanotubes (MWCNTs) consist of concentric cylinders nested inside each other, with outer diameters ranging from 2 to 100 nm.
This structural difference — sheet versus tube — determines almost everything about how the two materials behave and what they are useful for.
Aspect ratio. Graphene flakes are essentially two-dimensional with relatively low aspect ratios (lateral dimension to thickness). CNTs are extremely high aspect ratio structures — a single SWCNT might be 1 nm in diameter and 10 micrometers long, giving an aspect ratio of 10,000:1. This makes CNTs exceptionally effective at forming percolating networks at very low loading levels.
Surface area. Both materials have extremely high theoretical surface areas — approximately 2,630 m²/g for graphene and 1,315 m²/g for SWCNTs. In practice, graphene’s tendency to restack and CNTs’ tendency to bundle reduce effective surface areas significantly.
Chirality. CNTs have a property graphene lacks: chirality. The angle at which the graphene sheet is rolled determines whether a nanotube is metallic or semiconducting. Approximately one-third of SWCNTs are metallic and two-thirds are semiconducting, based on the statistical distribution of chiralities. This mix is a challenge for electronic applications that require one type or the other.
Property Comparison
Both materials exhibit extraordinary properties, but with important differences in magnitude and character.
Electrical conductivity. Both are excellent conductors, but their geometry makes them conductive in different ways. Graphene conducts electricity across a plane — it is an outstanding two-dimensional conductor. CNTs conduct along their length — they are outstanding one-dimensional conductors. Metallic SWCNTs can carry current densities exceeding 10⁹ A/cm², roughly 1,000 times higher than copper. For applications requiring electrical conductivity through a composite, CNTs’ high aspect ratio means they achieve percolation — forming a connected conductive network — at much lower loading levels (often 0.1–0.5 wt%) compared to graphene platelets (typically 1–3 wt%).
Mechanical properties. Both are among the strongest materials known. Graphene’s intrinsic tensile strength is approximately 130 GPa with a Young’s modulus of ~1 TPa. Individual SWCNTs have comparable values — tensile strengths of 50–150 GPa and moduli of 1–1.3 TPa. In composites, CNTs’ high aspect ratio provides better load transfer along the fiber direction, while graphene’s planar geometry distributes reinforcement more broadly across two dimensions.
Thermal conductivity. Graphene’s in-plane thermal conductivity (~5,000 W/m·K for suspended pristine monolayer) slightly exceeds that of individual SWCNTs (~3,500 W/m·K). However, graphene’s thermal conductivity is highly anisotropic — excellent in-plane, poor through-plane. CNTs can conduct heat efficiently along their axis, making them useful for directional thermal management.
Optical properties. Monolayer graphene absorbs exactly 2.3% of visible light, making it nearly transparent — useful for transparent conductor applications. CNTs, depending on their chirality and bundling, have more complex optical properties and are generally not used as transparent conductors except in very thin film form.
Production and Cost
The production landscapes for graphene and CNTs are at different stages of maturity, which significantly affects their commercial positioning.
Carbon nanotubes have a roughly 15-year head start in commercial production. Large-scale CNT manufacturing — primarily MWCNTs via catalytic chemical vapor deposition — has been established since the mid-2000s. Major producers include Nanocyl, Arkema (now through its Graphistrength line), OCSiAl (which has dramatically scaled SWCNT production), LG Chem, and Cabot. Global MWCNT production capacity exceeds several thousand tonnes per year. SWCNT production is smaller but growing rapidly, with OCSiAl’s TUBALL product being the most prominent large-scale SWCNT.
Pricing reflects this maturity difference. Industrial-grade MWCNTs are available at $50–$150/kg in volume, with some grades below $20/kg. OCSiAl’s SWCNTs have reached approximately $50–$100/kg at scale. Commercial graphene nanoplatelets range from $5–$100/kg depending on quality, with the cheapest grades being comparable to or less expensive than MWCNTs. High-quality few-layer graphene remains more expensive.
Graphene production is more fragmented, with dozens of small producers and fewer large-scale operations. NanoXplore (4,000 tonnes/year announced capacity for graphene nanoplatelets) is the largest, but the industry lacks the concentration of a few dominant suppliers that characterizes the CNT market.
Where Each Material Wins
The choice between graphene and CNTs for a given application is rarely about which material has “better” properties in the abstract. It depends on the specific performance requirement, the form factor, and the processing constraints.
CNTs are preferred when:
Electrical percolation at minimal loading is the priority. CNTs’ extreme aspect ratio means they form conductive networks through composites at 0.1–0.5 wt%, compared to 1–3 wt% for graphene. For applications like antistatic packaging, ESD protection, or adding conductivity to polymers without significantly changing mechanical properties, CNTs are more efficient.
One-dimensional reinforcement is needed. CNTs’ fiber-like geometry provides directional strengthening similar to short fiber reinforcement. They are effective in fiber-spinning applications where alignment can be controlled.
The existing formulation infrastructure is built for CNTs. Many industries — particularly automotive, electronics, and sporting goods — have established supply chains, qualification data, and processing know-how for CNTs. Switching to graphene requires requalification.
Graphene is preferred when:
Two-dimensional properties matter. Barrier coatings, thermal management films, and surface treatments benefit from graphene’s planar geometry. A sheet material covers area more efficiently than a tubular one.
Multifunctional property improvement is needed. Graphene simultaneously enhances mechanical, thermal, and electrical properties with a single additive. In applications like concrete, coatings, and certain composites, this breadth of improvement is more valuable than optimizing any single property.
Surface area and interface effects dominate. In energy storage applications (supercapacitor electrodes, battery anode coatings), graphene’s accessible surface area and planar geometry can be advantageous for ion transport and electron collection.
Cost-sensitive, high-volume applications favor bulk graphene. The cheapest graphene nanoplatelets are already competitive with or cheaper than MWCNTs per kilogram. For concrete, coatings, and other applications requiring tonnes of material, graphene’s cost trajectory may be more favorable.
Hybrid Approaches
An increasingly important development is the use of graphene and CNTs together. The two materials are not competitors in a hybrid composite — they are synergistic.
CNTs bridge between graphene platelets, creating three-dimensional conductive networks that neither material achieves alone. The CNTs prevent graphene restacking while the graphene platelets provide large surface area and planar reinforcement. Research has demonstrated that graphene-CNT hybrid fillers can achieve electrical percolation at lower total loading than either material alone, and can simultaneously improve mechanical properties by different mechanisms.
Commercial hybrid products are emerging, though they remain early-stage. The concept makes theoretical sense — combining the best geometry of each material to address the other’s limitations — and the experimental evidence is encouraging.
The Bigger Picture
The framing of graphene “versus” carbon nanotubes is largely a media and marketing construction. In practice, the two materials serve overlapping but distinct application spaces, and the choice between them is driven by specific engineering requirements rather than abstract property comparisons.
CNTs have a substantial commercial head start, an established supply chain, and proven performance in applications requiring electrical percolation at low loading. Graphene offers broader multifunctional improvement, cost advantages in high-volume applications, and geometric advantages for barrier and surface applications.
For engineers and procurement managers, the right question is not “which is better?” but “which material’s properties and geometry best match my application’s requirements, processing constraints, and cost targets?” Often the answer is clear once the question is framed correctly.
This article is part of our Fundamentals series. For a deeper comparison with another commonly confused carbon material, see Graphene vs. Carbon Fiber: What’s the Difference?. For practical guidance on selecting and procuring graphene, see Buying Graphene: A Procurement Guide.
