Oxygen Depolarized Cathode Patents: Leaders & Filing Trends 2026
- One assignee dominates the ranking. the leader holds 54 records against a fifth-place count of 3 and a tenth-place count of 1, across 20 ranked companies.
- Filing grew 67% from 2021 to 2024. activity climbed from 6 to 10 records in that span, with 2019 still the single peak year at 19 filings.
- Claims cluster hard in three IPC subclasses. C25B, B01D and C01D each appear in well over two-thirds of the 75 records in scope, leaving narrower classes comparatively open.
Filing growth compares 2021 (6 records) with 2024 (10) — 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.
What the oxygen depolarized cathode patent record shows
Oxygen depolarized cathode (ODC) technology replaces the hydrogen-evolving cathode in chlor-alkali electrolysis with a gas diffusion electrode that reduces oxygen instead, cutting cell voltage and energy consumption. The patent record captured here spans 75 published records filed between 2015 and mid-2026, drawing on search terms tied to voltage saving, gas diffusion electrode design, silver catalysts, oxygen supply purity, hydrogen loss tradeoffs and retrofit feasibility — the practical levers that determine whether an ODC retrofit pencils out against a conventional cell.
Filing activity peaked in 2019 and has not returned to that level since, though the 2021-2024 window shows renewed growth. Because publication typically lags filing by around 18 months, the most recent years in the trend understate actual filing activity and should not be read as a slowdown.
Filing trend and technology composition
The two views below cover the same 75 records from different angles: one tracks when filings were made, the other shows which IPC subclasses those filings sit in.
A peak in 2019, then a slower rebuild
Filings rose from 2 in 2017 to a peak of 19 in 2019, then eased before climbing again from 6 in 2021 to 10 in 2024, a 67% increase over that three-year span. 2025 and 2026 figures are still filling in due to publication lag and should not be read as a decline.
Concentration in electrolytic and separation classes
C25B (electrolytic production of compounds) appears in 94.7% of the 75 records, with B01D and C01D each at 68.0%. Water treatment (C02F, 29.3%), electrolytic metal production (C25C, 28.0%) and alkaline-earth compounds (C01F, 26.7%) appear less often, while C07C and C08G each sit at just 4.0%, marking the narrowest slices of claim activity.
Shares are the percentage of the 75 records in scope. A patent can carry several IPC classes, so the shares add up to more than 100%.
Go deeper on Oxygen Depolarized Cathode Technology with Eureka
This page is one run against one query. Ask Eureka your own question about oxygen depolarized cathode technology and every answer comes back with the patent numbers behind it.
Try EurekaThe most-cited records in this field
EP4227439A1 — Gas diffusion electrode for onsite chemical generation in lithium recovery
The filing describes a membrane electrolysis cell incorporating an oxygen depolarized cathode to generate acid, base and salt reagents onsite from lithium-containing brine or solid waste, recycling the chemicals a conventional lithium recovery process would otherwise consume. Simultaneous acid and base generation lets a single cell serve both sides of the recovery process, with desalinated water recovered as a byproduct stream.Filed by Mangrove Water Technologies, published 2023-08-16.
| # | Publication no. | Patent title | Citations |
|---|---|---|---|
| 1 | US4292197A | Method of preparing electrocatalyst for an oxygen depolarized cathode electrolytic cell | 19 |
| 2 | US20220042182A1 | Li recovery processes and onsite chemical production for li recovery processes | 18 |
| 3 | EP2371806A1 | Method for manufacturing diaryl carbonates and polycarbonates | 18 |
| 4 | WO2020128619A1 | Li recovery processes and onsite chemical production for li recovery processes | 13 |
| 5 | US4244793A | Brine electrolysis using fixed bed oxygen depolarized cathode chlor-alkali cell | 12 |
| 6 | US4313813A | Fixed bed oxygen depolarized cathode chlor-alkali cell | 7 |
| 7 | US20220380917A1 | Li recovery processes and onsite chemical production for li recovery processes | 3 |
| 8 | US20160160366A1 | Apparatus and method for operating an electrolysis with an oxygen depolarized cathode | 3 |
| 9 | US20220380914A1 | Li recovery processes and onsite chemical production for li recovery processes | 2 |
| 10 | US20190226098A1 | Methods And Systems For Production Of Chlorine And Caustic Using Oxygen Depolarized Cathode | 2 |
Citation counts favour older records that have had more time to accumulate citations within the searched corpus; treat them as a signal of influence rather than current relevance.
Each row carries its publication number; clicking a row searches Eureka by that number.
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Browse MCP servers →What the numbers mean for a filing decision
Three patterns in this dataset are useful for deciding where to file, where to license, and what to watch.
One assignee dominates the ranked field
The leading assignee holds 54 of the records tracked in the ranking, against 3 at fifth place and 1 at tenth. That gap suggests most of the remaining 19 ranked companies hold narrow, defensive positions rather than broad platform claims, so freedom-to-operate work should focus disproportionately on the leader's portfolio.
Renewed growth after the 2019 peak
Filings climbed from 6 in 2021 to 10 in 2024, a 67% increase, even though the field has not returned to its 2019 peak of 19. The rebound points to renewed commercial interest, likely tied to retrofit economics and energy costs, rather than a technology in decline.
Electrolytic production claims are the default
Nearly every record in scope touches C25B, the electrolytic production of compounds class, with B01D separation processes and C01D alkali-metal compounds each present in 68.0% of records. Narrower classes such as C07C and C08G, at 4.0% each, mark where claim density is thin.
Eureka can read the same corpus for gaps instead of for coverage: under-claimed branches adjacent to oxygen depolarized cathode technology, with the prior art for and against each one.
Who holds the claim space
The assignee ranking covers 20 companies counted in records; it is not a top-50 or top-100 list, it is the whole ranking the dataset returns.
A single leader with a wide margin
The top-ranked assignee holds 54 records against a fifth-place figure of just 3, a gap wide enough that most competitive activity in this field sits with one company rather than being spread across a cluster of comparable filers.
A thin band of secondary filers
Below the leader, filing counts drop off quickly: fifth place holds only 3 records and tenth place holds 1. That pattern is typical of a field where one platform holder set the technical baseline and later entrants filed narrow improvement claims around it.
Co-filing is limited but present
Ten co-assignee pairs appear in the dataset, with the strongest pairing linked to six shared records. Co-filing here looks more like inventor-to-assignee or joint-venture bookkeeping than a broad industry consortium.
| Assignee | Recent year | YoY |
|---|---|---|
| Mangrove Water Technologies Ltd. | 0 | — |
| thyssenkrupp Uhde Chlorine Engineers (Italia) S.r.l. | 0 | — |
| HOORMANN DIRK | 0 | — |
| Covestro Deutschland AG | 0 | — |
| Dioxide Materials, Inc. | 0 | — |
| WOLTERING PETER | 0 | — |
| TOROS PETER | 0 | — |
| PPG Industries, Inc. | 0 | — |
Where to take this analysis
The dataset points to a concentrated leader, a rebuilding filing trend, and several IPC branches with comparatively thin coverage. Turning that into a filing or licensing decision means going deeper on the specific claims involved.
Map freedom-to-operate against the leader's portfolio
With one assignee holding 54 of the ranked records, a targeted claim chart against that portfolio will do more for a filing decision than a broad landscape scan.
Explore claim charts in EurekaWatch the under-claimed branches
Silver catalyst loading, oxygen supply purity and hydrogen loss tradeoffs sit in narrower IPC classes than the core electrolytic claims, which is where a first-mover claim is more likely to hold.
Track white space in EurekaFrequently asked questions
An oxygen depolarized cathode (ODC) replaces the hydrogen-evolving reaction at the cathode of a chlor-alkali electrolysis cell with an oxygen-reduction reaction on a gas diffusion electrode. Because oxygen reduction requires a lower voltage than hydrogen evolution, the cell operates at a reduced overall voltage for the same chlorine output, which is where the energy saving comes from. The tradeoff is that hydrogen, previously a saleable byproduct, is no longer generated at the cathode, so plant operators have to weigh the voltage saving against the lost hydrogen value and the cost of oxygen supply.
The assignee ranking in this dataset covers 20 companies, with one assignee holding 54 of the records and a clear drop to 3 records at fifth place and 1 at tenth. That gap indicates the field is not evenly contested: one company has built a substantially larger patent position than the rest of the ranked filers combined. Anyone assessing freedom to operate should treat that leader's portfolio as the primary reference point rather than spreading diligence evenly across all 20 names.
Filing activity grew 67% between 2021 and 2024, rising from 6 to 10 records, even though the field has not returned to its 2019 peak of 19 filings. The years since 2024 show fewer records, but that is expected: patent publication typically lags actual filing by around 18 months, so the most recent years in any filing trend are always undercounted at the time of measurement. Based on the 2021-2024 trajectory, the technology shows renewed rather than declining interest.
Relative to the dominant electrolytic production classes, which cover the large majority of the 75 records in scope, narrower classes tied to acyclic compounds and condensation polymers each account for only 4.0% of records. Within the search scope itself, silver catalyst loading, oxygen supply purity control and hydrogen loss tradeoff management appear as claim themes without the dense coverage seen in core electrode and cell-design claims. These are reasonable areas to check for open claim space before committing to a filing strategy, though a full clearance search would need to confirm coverage beyond this dataset.
Retrofit feasibility is one of the specific technical themes this dataset was built around, alongside voltage saving and gas diffusion electrode design, because converting an existing cell line is a different engineering problem from designing a new plant around ODC from the start. Retrofit patents typically address how to fit a gas diffusion electrode and its oxygen supply into an existing cell housing without a full rebuild, and how to manage the loss of hydrogen byproduct revenue. Because this is a named search theme rather than a separate IPC class, assessing retrofit-specific coverage requires reading the individual filings rather than relying on class-level statistics alone.
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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.