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Run your analysis now →https://www.patsnap.com/resources/blog/rd-blog/alkaline-electrolyzer-environmental-durability-patent-landscape/ · Patsnap · data cut-off 2026-07-31 · downloaded from the live page
Hydrogen & Fuel Cells · Patent LandscapeAlkaline electrolyzer patents on environmental durability: who holds the corrosion and start-stop claims
- Filing has cooled from its 2018 peak. 22 families that year against 4 so far in the most recent (partial) year — durability claiming is past its first wave, not building toward one.
- Three assignees co-file as a tight cluster. Industrie De Nora S.p.A., Kawasaki Heavy Industries, Ltd. and Yokohama National University pair repeatedly, with the strongest link appearing in 26 shared families.
- Claim density sits almost entirely in one subclass. C25B carries all 132 records while B01J, H01M and the metallurgy classes (C22C, C21D) trail far behind — durability innovation is leaking into materials science faster than into core electrolysis claims.
132
Published Records
+7%
Filing Growth 2021→2024
EP
Leading Jurisdiction
32
Active Filers Ranked
Filing growth compares 2021 (14 records) with 2024 (15) — 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.
Published byPatsnap Research··7 min readSourced from Patsnap Eureka
Overview
What this landscape covers
This dataset tracks patent families where alkaline water electrolysis (AWE) claims intersect with environmental-durability language — dynamic operation durability, start-stop degradation, electrode stability and corrosion resistance — inside the core electrolytic-production IPC classes (C25B11, C25B15, C25B9). It is a narrow, mechanism-specific cut of the broader AWE literature, built to separate durability engineering from general electrolyzer design.
132 published families span 2015 through mid-2026. Filing activity peaked in 2018 and has since declined toward single digits, so the newest years understate true activity given the typical 18-month lag between filing and publication.
Filing activity by year
Source: Patsnap Eureka. Assignee ranking and totals. Derived from a Patsnap search on Alkaline Electrolyzer Environmental Durability covering 2015–2026, data cut-off 2026-07-31. Counts reflect published records only and shift as new filings publish.Run this in Eureka MCP
The data
Filing trend and technology composition
Two views of the same 132 families: when the claims were filed, and which IPC subclasses they touch beyond the core C25B group.
A front-loaded filing curve
Filings ran at 21-22 per year in 2017-2018, fell to roughly 5 by the midpoint year (2022), and sit at 4 in the latest partial year. The shape is consistent with a technology that had its main claiming wave already and is now being defended or extended rather than freshly staked out.
Durability claims lean on materials science
Every record sits in C25B (electrolytic production), but a meaningful share also touches B01J (catalysis, 21 records), H01M (fuel cells/batteries, 11), C22C (alloys, 7) and C21D (heat treatment of metals, 5). That spread shows corrosion and electrode-stability claims routinely reach into metallurgy and catalyst chemistry rather than staying confined to electrolyzer-cell architecture.
Shares are the percentage of the 132 records in scope. A patent can carry several IPC classes, so the shares add up to more than 100%.
Source: Patsnap Eureka. Filing trend and technology composition. Derived from a Patsnap search on Alkaline Electrolyzer Environmental Durability covering 2015–2026, data cut-off 2026-07-31. Counts reflect published records only and shift as new filings publish.
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The records other filings build on
Representative filing
US8632672B2 — Stainless steel anodes for alkaline water electrolysis and methods of making
GENERAL ELECTRIC COMPANY
The corrosion resistance of stainless steel anodes for use in alkaline water electrolysis was increased by immersion of the stainless steel anode into a caustic solution prior to electrolysis. Also disclosed herein are electrolyzers employing the so-treated stainless steel anodes. The pre-treatment process provides a stainless steel anode that has a higher corrosion resistance than an untreated stainless steel anode of the same composition.Assignee: General Electric Company · Published 2014-01-21
Most-cited records in this corpus
| # | Publication no. | Patent title | Citations |
|---|---|---|---|
| 1 | US20150203976A1 | Bipolar alkaline water electrolysis unit and electrolytic cell | 34 |
| 2 | US20160237578A1 | Anode for alkaline water electrolysis | 22 |
| 3 | EP3604620A1 | Water electrolysis system, water electrolysis method, and method for producing hydrogen | 18 |
| 4 | JP2008045205A | Stainless steel anode for alkaline water electrolysis, and manufacturing method for the same | 16 |
| 5 | US20210115573A1 | Electrolysis vessel for alkaline water electrolysis | 15 |
| 6 | US20200102663A1 | High-temperature alkaline water electrolysis using a composite electrolyte support membrane | 14 |
| 7 | EP3575439A1 | Electrolytic bath, electrolysis device, electrolysis method, and method for producing hydrogen | 13 |
| 8 | EP3388553A1 | Negative electrode, method for producing same, electrolytic cell using same, and hydrogen production method | 12 |
| 9 | EP3444383A1 | Positive electrode for alkaline water electrolysis and method for producing positive electrode for alkaline w… | 11 |
| 10 | US20190078220A1 | Anode for alkaline water electrolysis and method for producing anode for alkaline water electrolysis | 10 |
Citation counts are drawn from within this searched corpus and skew toward older filings simply because they have had longer to accumulate citations — read them as a signal of influence, not of present-day relevance.
Each row carries its publication number; clicking a row searches Eureka by that number.
Source: Patsnap Eureka. Citation counts and representative records. Derived from a Patsnap search on Alkaline Electrolyzer Environmental Durability covering 2015–2026, data cut-off 2026-07-31. Counts reflect published records only and shift as new filings publish.Run this in Eureka MCP
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What the numbers say about the field
Four read-outs from the filing trend, the IPC spread, receiving-office data and co-assignee links.
Filing momentum
22 → 4
peak (2018) vs. latest year
The main wave has passed
Filings ran at 21-22 per year through 2017-2018, dropped to about 5 by 2022, and sit at 4 in the newest partial year. Treat the last one to two years as understated because of publication lag, but the multi-year decline predates that effect.
Filing trend, 2017-2026
Technology spread
132 vs. 21
C25B records vs. B01J records
Catalysis is the largest adjacent claim zone
B01J (catalytic and physical processes) carries 21 records, more than double any other adjacent class. Anyone filing on electrode coatings or catalytic corrosion inhibition is filing into a zone that already overlaps two IPC groups.
IPC composition
Filing geography
45 EP · 23 US
leading receiving offices
Europe leads office-level filing
The EPO route accounts for the largest single share of receiving-office activity, ahead of the United States, with Australia, India, Canada and China each carrying smaller but non-trivial shares — a spread consistent with an industrial, export-oriented electrolyzer supply chain rather than a single-market technology.
Receiving offices
Collaboration pattern
26 shared families
strongest co-assignee pair
One cluster co-files repeatedly
Only 8 co-assignee pairs exist in this corpus, but the strongest pair shares 26 families and two other pairs among the same three organisations share 17 and 14. Durability IP here is concentrated in a tight, recurring collaboration rather than spread across many one-off partnerships.
Co-assignee pairs
Eureka AI Agent
Looking for what nobody has claimed yet?
Eureka can read the same corpus for gaps instead of for coverage: under-claimed branches adjacent to alkaline electrolyzer environmental durability, with the prior art for and against each one.
Source: Patsnap Eureka. Co-assignee relationships and derived observations. Derived from a Patsnap search on Alkaline Electrolyzer Environmental Durability covering 2015–2026, data cut-off 2026-07-31. Counts reflect published records only and shift as new filings publish.Run this in Eureka MCP
Players
Who is filing, and who has stopped
Assignee activity in this corpus is dominated by a small, recurring group, and recent-year momentum has gone flat across nearly all of them.
Core cluster
3 organisations
linked by repeated co-filing
Industrie De Nora S.p.A., Kawasaki Heavy Industries, Ltd. and Yokohama National University
These three names appear across all three of the strongest co-assignee pairs in the dataset, sharing 26, 17 and 14 families respectively. That pattern points to a sustained electrode-and-cell development partnership rather than incidental overlap.
Co-assignee pairs
Momentum check
0 in latest year
across most tracked assignees
Recent-year filing has gone quiet
Nippon Steel Corporation filed 1 family in the latest year (down 50% YoY) and Tokuyama Corporation fell 100% YoY to zero; Asahi Kasei Corporation, Industrie De Nora S.p.A., Kawasaki Heavy Industries, Ltd. and Yokohama National University all show zero in the latest year. This mirrors the overall filing decline rather than signalling any single firm's exit.
Recent-year momentum by assignee
Historic anchor
Cited 34x
most-cited record in corpus
US20150203976A1 sets the reference point
The bipolar alkaline water electrolysis unit and electrolytic cell filing carries the highest citation count in this corpus, ahead of anode-specific filings from the same period. New entrants should expect prior art searches in this space to surface this family early.
Most-cited records
Recent-year filing momentum
| Assignee | Recent year | YoY |
|---|---|---|
| Nippon Steel Corporation | 1 | -50% |
| Asahi Kasei Corporation | 0 | — |
| Industrie De Nora S.p.A. | 0 | — |
| Kawasaki Heavy Industries, Ltd. | 0 | — |
| Yokohama National University | 0 | — |
| Tokuyama Corporation | 0 | -100% |
| Hanwha Solutions Corporation | 0 | — |
| Juniper Green Energy Ltd. | 0 | — |
Source: Patsnap Eureka. Assignee-level momentum. Derived from a Patsnap search on Alkaline Electrolyzer Environmental Durability covering 2015–2026, data cut-off 2026-07-31. Counts reflect published records only and shift as new filings publish.Run this in Eureka MCP
What's next
Using this landscape
Two directions to take this analysis, depending on whether the goal is freedom-to-operate or identifying open claim space.
Check freedom-to-operate against the core cluster
Any filing touching stainless-steel anode treatment or bipolar cell architecture should be checked against the Industrie De Nora S.p.A. / Kawasaki Heavy Industries, Ltd. / Yokohama National University cluster and the older General Electric anode-treatment family before drafting claims.
Run a freedom-to-operate check in Eureka →Draft into the thin branches
Start-stop control logic, catalytic corrosion inhibition and alloy heat-treatment schedules carry far fewer filings than core electrode and cell claims, and are worth a closer novelty search before assuming the space is occupied.
Explore white space in Eureka →Source: Patsnap Eureka. Forward-looking reading of the same dataset. Derived from a Patsnap search on Alkaline Electrolyzer Environmental Durability covering 2015–2026, data cut-off 2026-07-31. Counts reflect published records only and shift as new filings publish.Run this in Eureka MCP
FAQ
Common questions on this landscape
In this dataset it refers to claims addressing how an electrolyzer or its components withstand operating stress over time — dynamic operation durability under variable renewable power, start-stop degradation from repeated shutdowns, electrode stability under prolonged current, and corrosion resistance of anodes, cathodes and cell hardware in caustic electrolyte. These are mechanism-specific claims, distinct from general electrolyzer design or efficiency patents. Most of the corpus sits in the core electrolytic-production IPC class C25B, with meaningful overlap into catalysis (B01J) and alloy metallurgy (C22C, C21D).
The most-cited record in this corpus is a bipolar alkaline water electrolysis unit and electrolytic cell filing (US20150203976A1, cited 34 times), followed by an anode-specific filing and a water electrolysis system filing. Citation counts favour older filings simply because they have had more time to accumulate citations, so treat this as a measure of historical influence rather than current dominance. On assignee activity, a small cluster of three organisations — Industrie De Nora S.p.A., Kawasaki Heavy Industries, Ltd. and Yokohama National University — appears repeatedly across the strongest co-assignee links in the dataset.
Filing peaked in 2018 at 22 families and has declined since, sitting at roughly 5 by 2022 and 4 in the latest partial year. That is a flat-to-declining trend, not a growth curve. The most recent one to two years should be read cautiously because publication typically lags filing by around 18 months, but the multi-year decline predates that lag effect and looks like a genuine cooling of new claiming activity.
US8632672B2, assigned to General Electric Company, claims a specific pre-treatment process: immersing a stainless steel anode in caustic solution before electrolysis to raise its corrosion resistance above an untreated anode of the same composition. It does not claim stainless steel anodes generally, or corrosion resistance achieved by other means such as alloying changes, coatings, or heat treatment. Companies working on caustic pre-soak or similar caustic-immersion pre-treatment steps for anode substrates should review this family closely; those working on alloy composition or coating-based corrosion resistance sit outside its narrower scope.
Relative to the dense core claims around electrode composition and cell architecture, this corpus shows thinner filing in start-stop cycling control logic, catalytic corrosion-inhibition coatings, and alloy heat-treatment schedules for anode durability — areas that show up in adjacent IPC classes (B01J, C22C, C21D) but at far lower volume than core C25B claims. These branches are worth a targeted novelty search rather than an assumption that the space is occupied, particularly since overall filing has slowed and few assignees are actively extending claims into them right now.
Answers are grounded in the same dataset. Derived from a Patsnap search on Alkaline Electrolyzer Environmental Durability covering 2015–2026, data cut-off 2026-07-31. Counts reflect published records only and shift as new filings publish.Run this in Eureka MCP
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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.