Fuel Cell Catalyst Layer Ionomer Patents: Leaders & Trends 2026
Filing growth compares 2021 (68 records) with 2024 (51) — a three-year span. 2024 is the most recent year we treat as complete: publication lags filing by roughly 18 months, so 2025 onwards are still filling in and any growth rate that ends there would understate the field. Top-5 share is the combined record count of the five largest assignees divided by all 1,202 records in scope (CR5), not by the ranked leaders only.
What the catalyst layer ionomer patent record shows
A catalyst layer ionomer is the proton-conducting polymer binder mixed with catalyst particles inside a fuel cell’s membrane electrode assembly. It governs how efficiently protons, electrons and reactant gases reach the catalyst surface, and it is one of the few components where a formulation change can shift both cost and durability at once. That makes it a persistent filing target across automotive OEMs, materials suppliers and catalyst specialists.
The scope tracked here spans 1,202 published records filed or published between 2015 and mid-2026, drawn from claims and titles referencing catalyst layer ionomer constructions within the fuel cell classification. Filing peaked in 2018 and has since eased, though recent years understate true activity because publication trails filing by roughly eighteen months.
The composition data below breaks the same 1,202 records down by International Patent Classification subclass, receiving office and citation weight, giving a view of where the claim density sits and which offices see the heaviest filing.
Filing trends and technology composition
The figures below cover all 1,202 records in scope. Because a single record can carry more than one IPC classification, the composition shares add to more than 100% — each percentage is measured against the full record count, not against other classes.
A 2018 peak followed by a cooling filing pace
Filings rose to a peak of 83 records in 2018, then eased through the following years. The 2021-to-2024 window, the most recent span that can be read as complete, shows a 25% decline from 68 to 51 records. 2025 and 2026 figures will rise as later publications catch up; they should not yet be read as a continued slide.
H01M dominates; C25B and B01J mark the adjacent chemistry
H01M (batteries, cells and fuel cells) covers 99.9% of records, confirming the search is anchored correctly on fuel cell technology. C25B (electrolytic production of compounds) reaches 16.0%, showing meaningful overlap with electrolyser and hydrogen production chemistry. B01J (catalysis processes, 11.5%) and C08J (polymer processing, 6.7%) mark the two next-largest adjacent branches, followed by coating (B05D, 5.3%) and laminate structure (B32B, 3.1%) classes.
Shares are the percentage of the 1,202 records in scope. A patent can carry several IPC classes, so the shares add up to more than 100%.
Go deeper on Fuel Cells: Catalyst Layer Ionomer Patent Landscape with Eureka
This page is one run against one query. Ask Eureka your own question about fuel cells: catalyst layer ionomer patent landscape and every answer comes back with the patent numbers behind it.
Try EurekaRepresentative filing and most-cited prior art
WO2024115878A1 — Recycling of catalyst coated membrane components
A method of recycling a waste catalyst coated membrane, wherein the waste catalyst coated membrane comprises a membrane including a membrane ionomer, a first catalyst layer disposed on one side of the membrane, the first catalyst layer comprising a first catalyst and a first catalyst layer ionomer, and a second catalyst layer disposed on an opposite side of the membrane, the second catalyst layer comprising a second catalyst and a second catalyst layer ionomer. The method is configured to recover the first and second catalyst layer ionomers in addition to the catalyst materials and membrane ionomer.Filed by Johnson Matthey, published 2024-06-06 — one of the few filings in this set aimed at end-of-life recovery rather than initial catalyst layer performance.
| # | Publication no. | Patent title | Citations |
|---|---|---|---|
| 1 | US6403245B1 | Materials and processes for providing fuel cells and active membranes | 230 |
| 2 | WO2007061945A2 | Nanowire structures comprising carbon | 204 |
| 3 | US5561000A | Gas diffusion electrode with catalyst for an electrochemical cell with solid electrolyte and method for makin… | 163 |
| 4 | US20080280169A1 | Nanowire structures comprising carbon | 143 |
| 5 | US20080206616A1 | Catalyst coated membranes and sprayable inks and processes for forming same | 131 |
| 6 | WO1992015121A1 | Membrane catalyst layer for fuel cells | 113 |
| 7 | US6309772B1 | Membrane-electrode unit for polymer electrolyte fuel cells and processes for their preparation | 107 |
| 8 | US6641862B1 | Preparation of fuel cell electrode assemblies | 98 |
| 9 | US6156449A | Catalyst layer for polymer electrolyte fuel cells | 96 |
| 10 | WO1997013287A2 | Flow field structures for membrane electrode assemblies of fuel cells | 82 |
Citation counts favour older filings simply because they have had longer to accumulate citations within the searched corpus; treat them as a measure of influence on later filers, not of current commercial relevance.
Each row carries its publication number; clicking a row searches Eureka by that number.
Put your own technology through the same analysis
Eureka on the web
When you want the answer in the next five minutes.
The agent works the prompt against patents and technical literature, citing every source.
Run your analysis now →MCP server & REST API
When it has to run inside your own pipeline.
Patent search, landscape analysis and assignee resolution as MCP tools. Drop them into any agent framework, or call REST directly.
Browse MCP servers →What the concentration and citation data mean for filing strategy
Three patterns stand out once the ranking, trend and citation data are read together: a concentrated top tier, a cooling but not collapsing filing pace, and prior art that still points to membrane and electrode fundamentals rather than catalyst layer ionomer specifics.
The top of the field is narrow
Five assignees account for 329 of the 1,202 records in scope, and the top ten reach 43.6% (524 records). Beyond the leader at 87 records, the count falls off quickly — fifth place sits at 52, tenth place at 31 — pointing to a small set of heavy filers surrounded by a long tail of single- or few-filing entrants.
Activity has eased from its 2018 peak
Filings peaked at 83 records in 2018 and the 2021-to-2024 window shows a 25% decline, from 68 down to 51 records. That is a real cooling in the most recent complete years, not a signal that the underlying chemistry is settled — later years in the trend will revise upward as publication catches up with filing.
Foundational membrane patents still anchor the field
The most-cited records in this corpus are membrane and electrode patents from the late 1990s and 2000s, including US6403245B1 and US5561000A, rather than catalyst layer ionomer-specific filings. New entrants should expect any catalyst layer ionomer claim to be read against this older membrane and electrode prior art, not just against recent competitors.
Electrolyser overlap is now material
C25B (electrolytic production of compounds) appears on 16.0% of the 1,202 records, the largest overlap outside the core H01M fuel cell class. Ionomer chemistry developed for catalyst layers is migrating into electrolyser and green hydrogen production claims, which widens the set of assignees worth watching beyond traditional automotive fuel cell filers.
Eureka can read the same corpus for gaps instead of for coverage: under-claimed branches adjacent to fuel cells: catalyst layer ionomer patent landscape, with the prior art for and against each one.
| Assignee | Co-assignee | Shared families |
|---|---|---|
| Kia Corporation | Hyundai Motor Company | 37 |
| Toyota Motor Corporation | Toyota Central R&D Labs, Inc. | 12 |
| Toyota Motor Corporation | Cataler Corporation | 7 |
| Ballard Power Systems Inc. | Johnson Matthey PLC (UK) | 5 |
| Ballard Power Systems Inc. | WILKINSON DAVID P | 4 |
| Ballard Power Systems Inc. | TAYLOR JARED L | 4 |
| Ballard Power Systems Inc. | KNIGHTS SHANNA D | 4 |
| Kolon Industries, Inc. | Korea Advanced Institute of Science and Technology (KAIST) | 3 |
Only 10 co-assignee pairs appear across the corpus, and the strongest pairing links two automotive groups at 37 shared records; most filings in this field are made by a single assignee acting alone.
Where to take this analysis next
The landscape above frames where filing has concentrated. Turning that into a filing or freedom-to-operate decision means going deeper into specific claim sets and adjacent branches.
Map the white space in adjacent IPC branches
C08G, B32B and B01D each sit under 7% of records — thin enough that a well-drafted claim in polymer condensation chemistry or laminate structure may face a shorter prior art chain than a core H01M filing.
Explore white space in EurekaTrace citation chains from the oldest anchor patents
US6403245B1 and US5561000A sit at the root of many later claims; understanding what they actually cover narrows the search for genuinely open catalyst layer ionomer claim territory.
Run a citation trace in EurekaWatch the electrolyser overlap for new entrants
The 16.0% overlap with C25B means hydrogen production companies without a fuel cell filing history may start appearing in this space; tracking new assignees early avoids surprises later.
Set up assignee monitoring in EurekaCommon questions about catalyst layer ionomer patents
The ranking covers 100 assignees, and it is led by a single company with 87 records, well ahead of the field. The top five assignees combined hold 329 records, 27.4% of the full 1,202-record set, and the top ten hold 43.6%. Beyond the leader, the count drops quickly — fifth place holds 52 records and tenth place holds 31 — which means the field has a concentrated top tier followed by a long tail of assignees with only a handful of filings each.
Filing peaked in 2018 at 83 records and has eased since. The clearest complete-year comparison available, 2021 to 2024, shows a 25% decline from 68 to 51 records. That said, 2025 and later figures will revise upward as publication catches up with actual filing dates, since publication typically lags filing by around eighteen months, so it is premature to call this a permanent decline based on the newest years alone.
A catalyst layer ionomer is the proton-conducting polymer binder that surrounds catalyst particles inside a fuel cell electrode, controlling how protons, electrons and reactant gases move to and from the catalyst surface. Because small formulation changes affect both durability and cost, it is one of the most frequently claimed components in fuel cell membrane electrode assembly design. The technology also overlaps with electrolyser chemistry, which is part of why C25B classifications appear on 16.0% of the records in this landscape.
Nearly all records, 99.9%, sit in H01M (batteries, cells and fuel cells), confirming the core focus. The next largest overlaps are C25B, electrolytic production of compounds, at 16.0% of records, and B01J, catalysis processes, at 11.5%. Smaller but notable overlaps include C08J polymer processing at 6.7%, B01D separation processes at 6.0%, and B05D coating processes at 5.3%. Because records can carry multiple classes, these percentages sum to more than 100% of the 1,202-record total.
WO2024115878A1, filed by Johnson Matthey and published in mid-2024, covers a method for recycling waste catalyst coated membranes by recovering the catalyst layer ionomer and membrane ionomer materials alongside the catalyst itself. It is a process claim aimed at end-of-life recovery, not a claim on catalyst layer ionomer composition or deposition. That means it does not block someone developing a new ionomer formulation or coating process, though anyone building a recycling or materials-recovery process for spent membrane electrode assemblies should review its claim scope closely.
Research Fuel Cells: Catalyst Layer Ionomer Patent Landscape in depth with Eureka
Go past this page: query the whole fuel cells: catalyst layer ionomer patent landscape corpus yourself, in your own scope.
Every answer comes back with patent numbers you can open.
Disclaimer. This page is generated from Patsnap Eureka data drawn from a limited snapshot of global patent and scientific-literature records, and is provided for general information and reference only.
Patent data carries inherent limitations: recent filings (typically the most recent 18–24 months) are under-counted due to standard publication lag; counts may be reported at either a patent-family or a patent-record basis and are not always directly comparable; classification, applicant-name, and citation data may contain errors, duplicates, or omissions; and the underlying search query defines and constrains the scope shown. As a result, the analysis may be incomplete or inaccurate and may not reflect the full technology landscape.
Nothing on this page constitutes an exhaustive prior-art, novelty, freedom-to-operate, or validity search, nor does it constitute legal, financial, investment, or professional advice, and it should not be relied upon as such. Any patent, commercial, or strategic decision should be verified independently and reviewed with qualified patent, legal, and domain professionals. Patsnap makes no warranties, express or implied, as to the accuracy, completeness, or fitness for any particular purpose of the information presented.
Machine translation. Assignee and organisation names originally recorded in Chinese, Japanese or Korean have been rendered into English by an AI translation step so that the tables stay readable. These renderings are best-effort and may not match a company’s registered English name; the original name is what the underlying patent record carries, and it is what any Eureka query launched from this page uses.