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Run your analysis now →https://www.patsnap.com/resources/blog/rd-blog/capacitive-deionization-advanced-materials-patent-landscape/ · Patsnap · data cut-off 2026-07-31 · downloaded from the live page
Water & Environmental · Patent LandscapeCapacitive Deionization Advanced Materials Patents
- Filing activity peaked in 2018 at 9 records and has not returned to that level since, with the 2022 midpoint sitting at just 2 — a flat-to-declining trend rather than a growing field.
- Water treatment claims dominate the IPC mix at 44 of 46 records, but earth-and-rock-drilling classifications appear in 12 records, pointing to oilfield water-injection use bleeding into this search.
- China leads receiving offices with 13 filings ahead of the United States at 11 and the EPO at 9, while co-assignment is rare — only two pairs across the whole set.
46
Published Records
59%
Top-5 Share of All Records
0%
Filing Growth 2021→2024
CN
Leading Jurisdiction
Filing growth compares 2021 (2 records) with 2024 (2) — 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 46 records in scope (CR5), not by the ranked leaders only.
Published byPatsnap Research··6 min readSourced from Patsnap Eureka
Overview
What this landscape covers
This set tracks patent families at the intersection of capacitive deionization (CDI) and advanced electrode materials — porous carbon, faradaic, MXene and ion-selective constructions — restricted to the core water-treatment and capacitor IPC classes (C02F1/469, H01G11/24, C02F1/461). It spans filings from 2015 through the 2026 cut-off, though the most recent year is necessarily undercounted because publication typically lags filing by around 18 months.
At 46 families total, this is a small, specialised corpus rather than a mass-filing field. That makes individual documents — and the small number of co-assignment pairs — more informative than they would be in a crowded category, but it also means rankings can shift with a handful of new filings.
Filing activity and technology composition, 2015-2026
Source: Patsnap Eureka. Assignee ranking and totals. Derived from a Patsnap search on Capacitive Deionization Advanced Materials 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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The data
Filing trend and technology composition
Two views of the same 46-family set: how filing activity has moved year over year, and which IPC subclasses the claims actually sit in.
Filing trend, 2017-2026
Activity rose to a peak of 9 records in 2018, then eased back; by the 2022 midpoint annual filings had fallen to 2, and the trend has stayed flat-to-declining since. Treat the final year or two as undercounted given typical publication lag.
IPC subclass composition
C02F (water and wastewater treatment) accounts for 44 of 46 records, confirming this is fundamentally a water-treatment corpus. The presence of B01D (separation processes) and, notably, E21B (drilling/wells) in 12 records signals a secondary cluster around oilfield water handling that shares classification codes with CDI electrode work; H01G (capacitors) at 7 marks the electrochemical-hardware side proper.
Shares are the percentage of the 46 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 Capacitive Deionization Advanced Materials covering 2015–2026, data cut-off 2026-07-31. Counts reflect published records only and shift as new filings publish.
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Most-cited records in this set
Representative filing
Method of manufacturing a CDI device, CDI device and apparatus for treating water, electrode for capacitive deionization and method of forming same
SINGAPORE UNIVERSITY OF TECHNOLOGY AND DESIGN
Filed via PCT and published as WO2018106186A1, this filing (rendered here under its Singapore national-phase number SG11201903410XA) covers a full device-and-method package: an electrosorptive electrode pair, a spacer compartment with a spacer layer, and surface plates, alongside a method of forming the electrode itself. It is the most-cited record in the set by a wide margin.Assignee and filing date are shown in the record card above; the abstract text is drawn directly from the published PCT front matter.
View full recordHighest-citation patents
| # | Publication no. | Patent title | Citations |
|---|---|---|---|
| 1 | WO2018106186A1 | Method of manufacturing capacitive deionization (CDI) device, CDI device and apparatus for treating water, el… | 30 |
| 2 | CN105731609A | 一种基于金属有机骨架材料的多孔碳电极及其制备方法 | 22 |
| 3 | US9085971B2 | Method and system for enhancing oil recovery (EOR) by injecting treated water into an oil bearing formation | 18 |
| 4 | CN104817144A | 一种电容去离子用聚多巴胺改性多孔碳电极的制备方法 | 13 |
| 5 | WO2013098193A1 | Method and system for enhancing oil recovery (EOR) by injecting treated water into an oil bearing formation | 13 |
| 6 | EP3708544A1 | Hybrid power generation apparatus and method capable of electricity production and deionization simultaneously | 10 |
| 7 | CN110033957A | 一种基于壳聚糖高温热解的多孔碳电极及其制备方法 | 9 |
| 8 | US20130206598A1 | Capacitive deionization apparatus | 6 |
| 9 | US20220119288A1 | Energy-saving ion adsorption/desorption water purification apparatus and energy-saving water purification met… | 4 |
| 10 | CN114380370A | 一种用于反硝化去除硝酸盐的杂化膜电容去离子装置及其使用方法 | 3 |
Citation counts are measured within this searched corpus and skew toward older filings that have had more time to accumulate citations — read them as a signal of influence, not of current commercial relevance.
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. 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 Capacitive Deionization Advanced Materials 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
Four figures worth pausing on before deciding where to file or who to watch.
Filing momentum
9 → 2
peak (2018) vs. 2022 midpoint
Growth has not been sustained
The field's busiest year was 2018, with 9 published records. By the 2022 midpoint, annual output had dropped to 2. That is a shrinking-interest pattern, not an emerging one — file here because the claim space is open, not because the market is heating up.
Based on 2017-2026 filing counts
Classification overlap
12 of 46
records also classified under E21B
An oilfield-water cluster sits inside this search
Twelve records carry earth-and-rock-drilling (E21B) codes alongside the CDI classes, and two of the five most-cited records concern enhanced oil recovery via treated-water injection rather than electrode chemistry. Anyone benchmarking pure CDI materials should separate this cluster out before drawing conclusions.
IPC composition, this dataset
Collaboration
2 pairs
co-assignee pairs across 46 families
Filers work alone
Only two co-assignment pairs appear in the whole set, one linking two Shell entities and one linking a Korean electronics major with a university foundation. Cross-organisation R&D partnerships are the exception here, not the norm.
Co-assignee pairs, this dataset
Geographic filing
China 13
leading receiving office, ahead of US (11) and EPO (9)
China is the largest single filing venue
China receives more filings than any other single office, with the United States and the EPO close behind. Smaller volumes at AT, DK and MY suggest occasional strategic filing rather than a broad multi-jurisdiction strategy from most assignees.
Receiving office counts, this dataset
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 capacitive deionization advanced materials, with the prior art for and against each one.
Source: Patsnap Eureka. Co-assignee relationships and derived observations. Derived from a Patsnap search on Capacitive Deionization Advanced Materials 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 where the field is open
Assignee activity in this corpus is dispersed rather than concentrated, and momentum has cooled across the board — none of the tracked assignees show filings in the latest year.
Momentum
0
latest-year filings across all tracked assignees
No assignee is currently active
Every assignee tracked for recent-year momentum — including the two Shell entities, Samsung, a Korean energy research institute and two other Korean players — shows zero filings in the latest year. That flat signal across the board fits the broader declining trend rather than any single company retreating.
Recent-year momentum, this dataset
Collaboration pattern
2
co-assignee pairs total
Corporate-university links are rare but present
The one non-corporate-only pairing links a Korean electronics major with a university industry foundation — a template other assignees have not widely repeated here. With only two pairs in 46 families, most filings are single-assignee efforts.
Co-assignee pairs, this dataset
Citation leadership
30 citations
top-cited record in the set
One device patent anchors the field's citation graph
The most-cited record in this corpus is a device-and-method filing covering electrode pairing, spacer construction and electrode formation — cited well ahead of the next entries. High citation counts here reflect age and breadth of claim, not necessarily current freedom-to-operate risk.
Most-cited records, this dataset
Recent-year filing momentum by assignee
| Assignee | Recent year | YoY |
|---|---|---|
| Shell International Research Maatschappij B.V. | 0 | — |
| Doosan Heavy Industries & Construction Co., Ltd. | 0 | — |
| Samsung Electronics Co., Ltd. (South Korea) | 0 | — |
| Korea Institute of Energy Research | 0 | — |
| Shell Oil Company | 0 | — |
| Zion Tech Co., Ltd. | 0 | — |
| Singapore University of Technology and Design | 0 | — |
| Changzhou University | 0 | — |
Source: Patsnap Eureka. Assignee-level momentum. Derived from a Patsnap search on Capacitive Deionization Advanced Materials 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
Where to take this
Two ways to go deeper than a static count of 46 families.
Separate the oilfield-water cluster
Before benchmarking electrode-materials novelty, pull out the E21B-classified records tied to enhanced oil recovery — they inflate the apparent size of the field without being CDI electrode art.
Explore the IPC breakdownWatch the citation leaders, not just the newest filings
With filing activity flat since 2018, the most useful signal in this corpus is which older, highly-cited patents define the claim boundaries that later filers had to design around.
Review the most-cited patentsSource: Patsnap Eureka. Forward-looking reading of the same dataset. Derived from a Patsnap search on Capacitive Deionization Advanced Materials 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
In this landscape, advanced materials means anything beyond plain activated-carbon electrodes: porous carbon electrodes with engineered pore structure, faradaic (redox-active) electrodes, MXene-based electrodes and ion-selective membrane materials. These categories were defined directly in the search string used to build this dataset, restricted further to the C02F1/469, H01G11/24 and C02F1/461 classification codes. Plain carbon-electrode CDI patents without one of these advanced-material claims fall outside this specific set, even though they belong to the broader CDI field.
Based on this dataset, filing activity peaked in 2018 at 9 published records and had fallen to just 2 by the 2022 midpoint, with no clear recovery since. That is a flat-to-declining pattern rather than a growth trend. The most recent year or two should be read cautiously, since publication typically lags actual filing by around 18 months, so 2025-2026 counts will rise somewhat as those applications publish.
China is the leading receiving office in this dataset with 13 filings, ahead of the United States at 11 and the European Patent Office at 9. Smaller volumes appear at the Austrian, Danish and Malaysian offices, suggesting occasional strategic national filings rather than broad multi-jurisdiction coverage by most assignees. This distribution reflects where applicants chose to seek protection, not necessarily where the underlying R&D took place.
Twelve of the 46 records in this set carry E21B classification codes, which cover drilling and well operations, alongside the CDI-related water-treatment codes. This happens because some patents describe treated-water injection for enhanced oil recovery, a use case that shares underlying water-treatment claim language with capacitive deionization even though the end application is oilfield operations rather than potable or industrial water purification. Two of the five most-cited records in this corpus fall into that oilfield-water cluster.
The clearest under-claimed branches in this dataset sit around MXene electrode surface functionalization, faradaic redox-active coatings purpose-built for CDI, and ion-selective membrane pairing with porous carbon electrodes — all thinly represented relative to the dominant water-treatment claims. Non-oilfield capacitor-class hardware integration, reflected in the small H01G subclass count, is also comparatively open. These are branches to check for prior art density before assuming the space is occupied, not guarantees of a clear path to grant.
Answers are grounded in the same dataset. Derived from a Patsnap search on Capacitive Deionization Advanced Materials 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.