ACC standards task force, now forming

A shared way to describe MXenes

ACC is convening producers, users and researchers to agree how MXenes are characterised, measured and named, and to put that consensus to ISO/TC 229 as the base document for a new ISO Technical Specification.

Join the task forceHow the process works
How an MXene is builtSchematic side view of an M3X2Tx MXene: three stacked flakes, each with three transition metal layers, two carbon or nitrogen layers and surface groups on both faces, ions between the layers, and one delaminated flake lifted above the stack.Delaminated flakeMultilayer stackTxSurface groups: O, OH, F, ClMTransition metal: Ti, V, Nb, MoXCarbon or nitrogenIntercalantsIons or molecules in the gaps

One name, a whole family of materials

“MXene” names a family, not a single material. One general formula covers more than 30 known compositions, and modelling suggests thousands more are possible.

Performance hinges on surface terminations and morphology, and terminations are set largely during etching. Two products sold under the same name can behave very differently, and there is not yet a shared way to describe what is being sold.

Use is moving out of the laboratory. Since 2012 there have been 35,183 MXene papers and 8,897 patent publications; since 2019, papers have grown more than sixfold and patents fivefold. Supply is moving from grams towards tonnes as new synthesis routes reach pilot scale, and each route sets its own surface chemistry and purity. Buyers need one basis to compare them.

No ISO or IEC document yet classifies commercial MXenes. A framework agreed now can shape data sheets before inconsistent conventions set in.

Mn+1XnTx
M
A transition metal such as Ti, V, Nb, Mo or Ta
X
Carbon or nitrogen
n
1, 2 or 3, giving M2X, M3X2 or M4X3
Tx
Surface groups such as O, OH, F or Cl

Two products sold as Ti3C2Tx can differ where it matters

Surface terminations
The mix of O, OH, F and Cl, set largely during etching
Layer state
Multilayer powder or delaminated single flakes
Flake size
Lateral size and thickness distributions
Phase purity
Residual MAX phase and etching by-products
Oxidation
Oxide content that grows with age and storage
Intercalants
Ions or molecules left between the layers

Patents cluster in product categories

Share of MXene publications in each application area that are patents

Share of MXene publications in each application area that are patents
AreaShare
Coatings48%
Textiles43%
Membranes39%
Flame retardants37%

Interest is spreading beyond Ti3C2: Ti2C, V2C and Nb2C show high patent intensity despite lower publication volumes, so a standard has to cover the family, not one compound.

Source: CAS Content Collection, via CAS Insights, June 2026

Five elements, modelled on the graphene framework

The framework will mirror the five elements of ISO/TS 9651:2025, the classification framework for graphene-related 2D materials that ACC took from task force to published standard. That way ISO/TC 229 sees a proven structure applied to a new family.

  1. a) Characteristics

    The properties that matter for commercial use. Candidates include composition (M, X and n), surface terminations, layer state, lateral flake size, thickness, phase purity and residual MAX phase, oxide content and intercalants.

  2. b) Measurement methods

    A preferred method for each characteristic, plus alternatives, favouring methods that are practical for batch-to-batch quality control. Candidates include XRD, XPS, Raman, SEM and TEM, AFM, ICP-OES, TGA and the sheet resistance of films.

  3. c) Value ranges

    Classes where they apply, such as layer state and flake size, and limits for residual MAX phase and oxide content.

  4. d) Naming syntax

    One consistent name built from composition, terminations, layer state and form, for example: Ti3C2Tx, delaminated, aqueous dispersion.

  5. e) Data sheet template

    A minimum data set for every product, including production and test dates and storage conditions, because MXenes are prone to oxidation.

Consensus through a modified Delphi process

Panellists answer short online questionnaires in rounds. After each round, everyone sees the anonymised group result and can revise their view in the next.

The method reaches experts across time zones without meetings, stops any one producer or senior voice from dominating, and leaves an auditable record of how consensus formed. That record becomes evidence for the ISO proposal.

  1. Round 0: Prepare

    ACC project team

    We ask
    Build a seed list of characteristics and methods from the literature and our ISO/TS 9651 experience
    Format
    Desk research
    Output
    Round 1 questionnaire

  2. Round 1: Explore

    We ask
    Which characteristics define and differentiate a commercial MXene? Which matter for your application? How do you measure each? What is in scope?
    Format
    Open questions, plus the seed list to add to or strike out
    Output
    Consolidated long list

  3. Round 2: Rate

    We ask
    How important is each characteristic? How suitable and available is each method?
    Format
    1 to 9 scale with comments
    Output
    Agreed items, with contested items flagged

  4. Round 3: Converge

    We ask
    Re-rate contested items against the group result, and propose classes, value ranges and naming
    Format
    Ratings plus draft ranges
    Output
    Draft framework

  5. Round 4: Confirm, if needed

    We ask
    Settle what remains and review the data sheet template
    Format
    Accept or amend
    Output
    Final draft for ISO
123
Out
456
Re-rate
789
In

An item is in when at least 70% of panellists rate it 7 to 9, out when at least 70% rate it 1 to 3, and re-rated otherwise.

Each round is open for two weeks, followed by two weeks of analysis and feedback. The process stops after four rounds, or sooner if ratings stop moving.

Who should take part

Producers and suppliers
Companies making or selling MXenes at any scale, from research grams to pilot volumes.
End users and product developers
Teams specifying MXenes for coatings, energy storage, EMI shielding, membranes, textiles and other uses.
Researchers
University and institute groups working on synthesis, characterisation or applications.
Testing and characterisation laboratories
Labs that measure MXenes and can judge which methods suit quality control.
Standards, regulatory and government bodies
Including national mirror committees of ISO/TC 229.

What it involves

Your time
Three to four online rounds, each open for two weeks. Answer on your own schedule, in more than one sitting if you need to.
Anonymity
Other panellists will not know who you are. ACC, as facilitator, does, and results are reported by stakeholder group.
No sensitive data
We never ask for prices, capacities, customers or other commercially sensitive information, in line with competition law.
Your contribution
By joining, you agree that your input may be used, anonymised, in the framework draft ACC submits to ISO.

Questions

How much time will it take?

Three to four rounds over about five months. Each round stays open for two weeks and can be completed in more than one sitting.

Will other panellists know who I am?

No. Panellists are anonymous to each other. ACC, as facilitator, knows who took part, and results are reported by stakeholder group rather than by person or company.

What happens to my answers?

After each round they are combined into the anonymised group result. At the end they feed the framework draft ACC submits to ISO/TC 229, and the round-by-round record shows how consensus formed.

Will you ask for commercially sensitive information?

No. We do not collect prices, capacities, customers or other commercially sensitive data.

Can colleagues take part?

Yes. Each person joins individually, so share this page with anyone who should be involved.

What will the framework cover?

That is a first-round question for the panel: carbides, nitrides and carbonitrides, and forms such as powder, dispersion and film.

Join the task force

Enter your work email and we will send you a secure link. If we already hold your details they will be filled in for you, so confirming them and joining takes about two minutes.

Questions about the task force? Email Terrance Barkan at [email protected].