Capacitive Deionization Environmental Durability Patent Landscape 2026
- 13 families total, a small, still-consolidating corpus rather than a crowded field — filing peaked in 2019 at 5 and has not repeated that level since.
- United States dominates receiving offices, with 7 of the filings, ahead of China's 2 and India's 2 — durability claims are being tested in the US first.
- Zero co-assignee clustering beyond one lab, the strongest pairing is a single university foundation and its named inventors — durability engineering here is still an individual-lab activity, not a joint-venture one.
Filing growth compares 2021 (1 records) with 2024 (0) — 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 this landscape covers
This landscape isolates patent families that combine capacitive deionization (CDI) or membrane capacitive deionization (MCDI) terms with durability-specific language — fouling resistance, electrode oxidation resistance, long-term stability and chlorine tolerance — inside IPC classes covering water treatment electrodes and capacitor-type deionization hardware. It is a narrow cut deliberately: broad CDI searches return electrode chemistry and cell-architecture filings that never address how the device holds up over repeated cycles or exposure to scale-forming ions and oxidants.
At 13 families, the dataset is small enough that individual assignees and even individual documents move the picture. Read the rankings and the trend line with that in mind — this is a landscape of who has staked an early claim, not yet a landscape of settled market leaders.
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Filing trend and technology composition
Two views of the same 13 families: when they were filed, and which parts of the IPC tree they sit in.
Filing trend, 2017–2026
Filings were at zero in 2017, rose to a peak of 5 in 2019, and had fallen back to zero by the 2022 midpoint. Because publication lags filing by roughly 18 months, the 2025-2026 tail understates whatever has actually been filed most recently — but the 2019 peak and the subsequent decline through 2022 are real signal, not an artefact of the lag.
Technology composition by IPC subclass
Every one of the 13 families sits in C02F (water and wastewater treatment); 4 of them also carry a B01D (separation processes) classification, meaning the durability claim is bundled with a filtration or membrane-separation mechanism rather than standing alone as an electrode-only invention.
Shares are the percentage of the 13 records in scope. A patent can carry several IPC classes, so the shares add up to more than 100%.
Go deeper on Capacitive Deionization Environmental Durability with Eureka
This page is one run against one query. Ask Eureka your own question about capacitive deionization environmental durability and every answer comes back with the patent numbers behind it.
Try EurekaThe most-cited documents in this corpus
US10793450B2 — Potential of zero charge-based capacitive deionization
The invention is a capacitive, aka electrostatic, deionization apparatus and method that solves the problem of short lifetime of conventional capacitive deionization (CDI) and of membrane capacitive deionization (MCDI) devices and methods by shifting the Potential of Zero Charge of electrode surfaces through surface modifications. Such electrode surface modifications provide very long lifetime capacitive deionization devices and methods.Filed by University of Kentucky Research Foundation, granted 2020-10-06 — the corpus's clearest statement that durability is being solved as an electrode-surface problem, not a system-architecture one.
| # | Publication no. | Patent title | Citations |
|---|---|---|---|
| 1 | US20200071200A1 | Electrodes for selective removal of multivalent ions through capacitive deionization | 20 |
| 2 | US20160167984A1 | Potential of Zero charge-Based Capacitive Deionization | 17 |
| 3 | CN217650954U | 一种有效抑制结垢的流动电极电容去离子装置 | 8 |
| 4 | US20190308893A1 | Bipolar CDI electrode, bipolar CDI electrode module and water treatment apparatus using the same | 7 |
| 5 | US10793450B2 | Potential of zero charge-based capacitive deionization | 5 |
| 6 | KR1020190115963A | Bipolar CDI electrode, bipolar CID electrode module and water treatment apparatus using the same | 4 |
| 7 | US11739010B2 | Electrodes for selective removal of multivalent ions through capacitive deionization | 3 |
| 8 | CN110342614A | 双极CDI电极、双极CDI电极模块及包含它的水处理装置 | 2 |
Citation counts inside this corpus skew toward older filings simply because they have had longer to accumulate citations — read this as a map of influence on later filers, not a ranking of current commercial strength.
Patent titles are shown in the language they were filed in, not translated, so that each record stays verifiable against the original filing — a translated title will not match in Eureka or in any national register. Publication numbers are shown where the record carries one (8 of 8 rows); clicking a row searches Eureka by that number.
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Browse MCP servers →What the numbers say about the field
Three readings of the same small, US-weighted dataset.
A single burst, not a sustained wave
Nearly forty percent of the entire corpus was filed in one year, 2019, with the midpoint year 2022 back down at zero. That shape is more consistent with a handful of labs staking early claims around the same time than with an industry ramping up investment year over year.
The US is where durability claims are being tested first
Seven of the thirteen families were filed at the USPTO, more than China (2) and India (2) combined. A WIPO/PCT filing and a single South Korean filing round out the set — durability-specific CDI claims have not yet been pursued as a broad multi-jurisdiction strategy by any one assignee.
Most durability claims stand alone in C02F
All 13 families sit in C02F, water and wastewater treatment, but only 4 also carry a B01D separation-process classification. The majority of durability inventions are being claimed as electrode or cell modifications rather than as filtration-system combinations.
Eureka can read the same corpus for gaps instead of for coverage: under-claimed branches adjacent to capacitive deionization environmental durability, with the prior art for and against each one.
| Assignee | Co-assignee | Shared families |
|---|---|---|
| University of Kentucky Research Foundation | OMOSEBI AYOKUNLE | 1 |
| University of Kentucky Research Foundation | LIU KUNLEI | 1 |
| University of Kentucky Research Foundation | LANDON JAMES RICHARDSON | 1 |
| University of Kentucky Research Foundation | GAO XIN | 1 |
| OMOSEBI AYOKUNLE | LIU KUNLEI | 1 |
| OMOSEBI AYOKUNLE | LANDON JAMES RICHARDSON | 1 |
| OMOSEBI AYOKUNLE | GAO XIN | 1 |
| LIU KUNLEI | LANDON JAMES RICHARDSON | 1 |
Ten co-assignee pairs exist across the dataset, and the strongest of them link a single university research foundation to its own named inventors rather than to an external corporate or institutional partner — evidence that durability engineering in CDI is still largely a single-lab activity.
Who holds the durability claims
Assignee activity is concentrated among a small set of universities and one industrial player, and none of them show filing momentum in the latest tracked year.
University of Kentucky Research Foundation
Holds the corpus's most-cited durability patent, US10793450B2, built around shifting the potential of zero charge at the electrode surface. Its co-assignee links are to its own named inventors rather than external partners.
Doosan Heavy Industries (Doosan Heavy Industries Co., Ltd.)
The one clearly industrial assignee in the ranking, filing from a water-treatment-equipment manufacturing base rather than a research-lab one — a useful signal that durability claims are not exclusively an academic pursuit.
Tongji University
One of two Chinese-affiliated entities in the ranking; its presence lines up with China's 2 receiving-office filings in this corpus, suggesting durability-specific CDI research is being pursued domestically rather than filed abroad.
| Assignee | Recent year | YoY |
|---|---|---|
| University of Kentucky Research Foundation | 0 | — |
| Doosan Heavy Industries Co., Ltd. | 0 | — |
| William Marsh Rice University | 0 | — |
| Tongji University | 0 | — |
| OMOSEBI AYOKUNLE | 0 | — |
| LIU KUNLEI | 0 | — |
| LANDON JAMES RICHARDSON | 0 | — |
| GAO XIN | 0 | — |
Where to take this
The corpus is small enough that a targeted claim search and a freedom-to-operate check are both tractable in a single pass.
Map the electrode-surface claim space
Given that the most-cited patent in this set solves durability through a potential-of-zero-charge surface modification, any new electrode-coating or surface-treatment approach should be checked against that claim scope before development spend goes further.
Explore electrode claims in EurekaWatch chlorine-tolerance and anti-fouling niches
Neither sub-area carries dense claim coverage in this dataset, which makes them a lower-risk place to file a first claim rather than a crowded one.
Run a white-space search in EurekaCommon questions about this landscape
This landscape identifies 13 patent families that combine capacitive deionization or membrane capacitive deionization terminology with durability-specific language such as fouling resistance, electrode oxidation resistance, long-term stability or chlorine tolerance, filed between 2015 and the 2026 data cut-off. That is a small subset of the much larger general CDI patent literature, because most CDI filings address electrode chemistry, cell architecture or ion selectivity without making a durability claim. Thirteen families is small enough that a single assignee's filing decisions can visibly shift the yearly trend, so any trend read from this data should be treated as directional rather than statistically robust.
The data shows a peak of 5 families in 2019 against a midpoint of zero in 2022, which is more consistent with a short burst of related filings from a small number of labs than with a sustained industry investment cycle. Because patent publication typically lags the underlying filing date by around 18 months, the apparent decline after 2019 is partly real and partly an artefact of more recent filings not yet having published. Readers should not treat the 2024-2026 figures as a confirmed downturn until later publication cycles catch up.
University of Kentucky Research Foundation holds the two most-cited documents in this corpus, both centred on a potential-of-zero-charge approach to extending electrode lifetime. Doosan Heavy Industries and Tongji University also appear in the assignee ranking, representing an industrial water-treatment manufacturer and a Chinese research university respectively. None of the tracked assignees show filing activity in the most recent tracked year, which is consistent with the overall flat-to-declining trend rather than any one organization losing ground specifically.
Based on the technology composition and citation patterns in this corpus, chlorine-tolerant current collectors, anti-scaling flow-electrode geometries and membrane-electrode interface stability coatings show little dedicated claim coverage relative to core electrode-surface modification claims. Only 4 of the 13 families combine a durability claim with a separation-process (B01D) classification, suggesting that durability claims bundled with filtration-system mechanisms are less contested than standalone electrode claims. Anyone filing in these adjacent areas is filing into comparatively open claim space rather than around an established leader's patent.
That depends on the specific mechanism used to achieve chlorine tolerance and cannot be answered from aggregate landscape data alone; a proper freedom-to-operate opinion requires a claim-by-claim comparison against the granted patents in this corpus, particularly the potential-of-zero-charge family US10793450B2 and the multivalent-ion selective electrode family US20200071200A1. What this landscape does show is that chlorine tolerance is not the primary subject of the most-cited patents here, which are built around potential-of-zero-charge surface modification and multivalent-ion selectivity rather than oxidant resistance specifically. That gap is a reasonable starting point for a design-around search, but it is not a substitute for one.
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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.