CDI Brackish Desalination Patent Landscape 2026
Capacitive deionization for brackish desalination is a maturing, concentrated field that peaked in 2018 and has since eased, with Unilever entities and Lawrence Livermore National Security dominating filings. The top five filers account for 31% of the hundred largest filers’ combined patent records, signaling a tiered competitive structure with room for targeted entry in adjacent materials branches.
Unilever and Lawrence Livermore lead a concentrated but maturing field
Among the hundred largest filers, Unilever NV leads with 31 patent records, closely followed by Unilever PLC (30 records), Lawrence Livermore National Security LLC (26 records), Samsung Electronics (23 records), and Doosan Heavy Industries & Construction (19 records). These five together hold 31% of the top-100 filers’ combined total, confirming a concentrated but not monopolistic competitive structure.
A clear tier gap separates the top two Unilever entities and Lawrence Livermore from mid-tier players such as Siontech and Voltea (15 records each) and Stockholm Water Technology AB (14 records). Below that, a long tail of academic institutions and smaller commercial players each contribute fewer than 15 patent records.
| # | Applicant | Patent records | Share |
|---|---|---|---|
| 1 | Unilever NV | 31 | |
| 2 | Unilever PLC | 30 | |
| 3 | Lawrence Livermore National Security LLC | 26 | |
| 4 | Samsung Electronics Co Ltd | 23 | |
| 5 | DOOSAN HEAVY IND & CONSTR CO LTD | 19 | |
| 6 | Siontech | 15 | |
| 7 | Voltea | 15 | |
| 8 | Stockholm Water Technology AB | 14 | |
| 9 | DWI Leibniz Institute for Interactive Materials EV | 13 | |
| 10 | Kyungdong Navien Co Ltd | 13 |
| # | Applicant | Patent records | Share |
|---|---|---|---|
| 11 | EcoWater Systems LLC | 11 | |
| 12 | UT-Battelle LLC | 8 | |
| 13 | VecEnergy Aegir LLC | 7 | |
| 14 | FUNDACION TECNALIA RESEARCH & INNOVATION | 7 | |
| 15 | TDS Select LLC | 7 | |
| 16 | University of Kentucky Research Foundation | 6 | |
| 17 | Foshan Shunde Midea Water Dispenser Manufacturing Co Ltd | 6 | |
| 18 | KOREA ADVANCED INST OF SCI & TECH | 6 | |
| 19 | Midea Group Co Ltd | 6 | |
| 20 | ABB POWER T&D CO INC | 6 |
Unilever’s dual-entity position—filing under both Unilever NV and Unilever PLC—effectively concentrates the largest share of CDI brackish desalination intellectual property within a single corporate group, giving it significant leverage over core water-treatment and capacitor-based process claims. Lawrence Livermore’s strong presence reflects sustained US government-funded research in electrode materials and process design.
Filing counts for 2024–2026 are subject to publication lag and will rise as pending applications publish; the apparent recent dip should not be read as a structural exit from the field. Longer-window growth, applicant concentration, and technology-route coverage are therefore more reliable signals than the latest-year bar alone.
Activity peaked in 2018 and has eased; C02F dominates but electrode-materials branches add depth
Two charts together capture the pace of innovation and its technical focus: the annual filing trend shows when competitive intensity was highest, while the IPC branch breakdown reveals which engineering disciplines underpin CDI brackish desalination work.
Annual filing trend
Filings climbed from 27 patent records in 2017 to a peak of 40 in 2018, then retreated steadily to the mid-teens through 2022 before a partial recovery to 25 in 2023. The 2024–2026 bars are suppressed by publication lag and should not be read as further decline. The overall trajectory places this field in a post-peak phase on a multi-year basis.
↗ Hover for values · click a bar to ask EurekaTechnology composition
C02F (Water & wastewater treatment) is the dominant IPC class with 383 patent records, reflecting the core desalination process claims. Secondary branches—B01D (Separation processes, 62 records), H01G (Capacitors, 47 records), C25B (Electrolytic production, 41 records), and C01B (Non-metallic elements & inorganic compounds, 27 records)—reveal active but smaller clusters around electrode materials, electrochemical engineering, and carbon-based media. H01M (Batteries, cells & fuel cells, 24 records) and B01J (Chemical/physical processes & catalysis, 14 records) round out the mid-tier branches.
↗ Hover for values · click a bar to ask EurekaHighly cited patent families surfaced by the query
Citation-heavy patent families returned by the query. Use this section as citation context, not as a curated list of the most topic-specific patents.
Method of manufacturing capacitive deionization (C…
WO 18/ 106 186 Al (12) INTERNATIONAL APPLICATI ON PUBLISHED UNDER THE PATENT COOPERATION TREATY (PCT) (19) World Intellectual Property Organization International Bureau (43) International Publication Date 14 June 2018 (14.06.2018) WIPO I PCT omit °nolo ono mom oimIE (10) International Publication Number WO 2018/106186 Al f START \ I Pone pair of… (excerpt from the patent abstract)
Open this patent in Eureka →| # | Patent | Citations |
|---|---|---|
| 1 | Method and apparatus for capacitive deionization a… | 368 |
| 2 | Alternating-polarity operation for complete regene… | 105 |
| 3 | Polarized Electrode for Flow-through Capacitive De… | 76 |
| 4 | Carbon composition with hierarchical porosity, and… | 47 |
| 5 | Water purification system and method | 47 |
| 6 | Alternating-polarity operation for complete regene… | 46 |
| 7 | Alternating-polarity operation for complete regene… | 44 |
| 8 | Alternating-polarity operation for complete regene… | 39 |
Ranked by total forward citations. Citation counts favour older and broadly cited patent families, and broad or adjacent patents may appear when they match the search scope. Treat this section as citation context, not as a curated list of the most topic-specific patents. Some patent titles may be shown in their original, non-English language where an accurate translation could not be guaranteed.
What the competitive structure means for R&D investment decisions
Reading concentration, maturity, collaboration patterns, and geographic spread together provides a clearer picture of where defensive filing has saturated the space and where new investment can still differentiate.
Post-peak field with eased annual volume
The lifecycle stage is Decline, with annual filings having eased back from the 2018 peak of 40 patent records. On a multi-year basis the field is still active, but the directional signal is consolidation rather than expansion. New entrants face a body of prior art that is dense in core C02F water-treatment claims, making differentiation in adjacent materials or process-control branches more viable than frontal attack on established positions.
Lifecycle: DeclineDual-entity leader with a clear tier gap
The top five filers account for 31% of the hundred largest filers’ combined patent records. Unilever’s two corporate entities collectively dominate the ranking, and Lawrence Livermore holds the leading US-government position. Mid-tier players—Siontech, Voltea, Stockholm Water Technology—each hold meaningful but substantially smaller portfolios. This structure means core process claims are heavily defended at the top, while the mid-tier leaves room for focused portfolio-building in under-covered branches.
Top-5 share: 31%Intra-group and strategic partnerships drive co-filing
The most active co-filing pair is Unilever NV and Unilever PLC (19 joint patent records), which is primarily an intra-group coordination mechanism rather than an external alliance. The next most active pairing is Siontech and Kyungdong Navien (6 joint records), signaling a product-development partnership between a CDI specialist and a heating/water systems OEM. Unilever entities also co-file with Conopco Inc (5 records each) and Hindustan Unilever Ltd (2 records each). Lawrence Livermore National Security LLC and the Regents of the University of Minnesota share 2 joint records, representing a government-lab/university collaboration on electrode science.
Co-filing: activeUS-first filing with strong Korean and European prosecution
The United States leads with 109 patent records, followed by Europe (EPO) at 64, South Korea at 49, and WIPO (PCT) at 45. China (26 records) and India (19 records) are secondary prosecution markets reflecting emerging domestic demand for brackish water treatment. The broad US/EPO/KR/PCT spread by the leading applicants indicates global commercial intent rather than home-market-only positioning.
Lead office: USGo beyond the landscape: Eureka’s TRIZ Solution agent breaks down an R&D problem and returns patented concept solutions, each with a technical approach and cited patent & literature evidence.
| Applicant | Collaborator | Co-filings |
|---|---|---|
| Unilever NV | Unilever PLC | 19 |
| Siontech | Kyungdong Navien Co Ltd | 6 |
| Unilever NV | Conopco Inc | 5 |
| Unilever PLC | Conopco Inc | 5 |
| Unilever NV | Hindustan Unilever Ltd | 2 |
| Unilever PLC | Hindustan Unilever Ltd | 2 |
| Lawrence Livermore National Security LLC | Regents of the University of Minnesota | 2 |
Co-filing pairs, ranked by the number of jointly-filed patent families.
Unilever dominates core treatment claims; Lawrence Livermore anchors electrode-materials R&D
The top players differ meaningfully in technology emphasis: Unilever focuses on end-to-end water-treatment and capacitor integration, while Lawrence Livermore leans into advanced carbon materials and inorganic chemistry for electrode engineering.
Unilever NV
Unilever NV holds 31 patent records, with its technology focus concentrated in C02F 1 (water & wastewater treatment, 33 subclass records) and H01G 11 (capacitors, 8 records), reflecting ownership of both the desalination process and the CDI cell architecture. When combined with the closely related Unilever PLC portfolio (30 patent records, similar focus), the corporate group is the single largest force in this landscape. Momentum data for the Unilever entities is not separately listed in the recent-filing trend, consistent with their established rather than newly emerging position.
Patent records: 31Lawrence Livermore National Security LLC
Lawrence Livermore National Security LLC holds 26 patent records and shows a trend flagged as a new entrant in recent filing windows, indicating recent activity from a relatively small prior-period base. Its technology emphasis sits in C02F 1 (water & wastewater treatment, 18 subclass records) and C01B 32 (non-metallic elements & inorganic compounds, 5 records), pointing to a research-driven focus on novel carbon and inorganic electrode materials rather than commercial system design. This positions the lab as a key source of upstream materials IP that downstream system builders may need to license.
Patent records: 26| Applicant | Recent (3 yrs) | Trend |
|---|---|---|
| Samsung Electronics Co Ltd | 2 | ▲ new entrant |
| Lawrence Livermore National Security LLC | 3 | ▲ new entrant |
| Stockholm Water Technology AB | 4 | ▲ new entrant |
Under-served electrode-materials and electrochemical branches adjacent to core CDI filings
While C02F anchors the corpus, several adjacent IPC branches carry meaningful but comparatively sparse patent-record counts. These observations point to areas where technical depth is lower relative to the core, which may reward targeted investment by teams with relevant materials or electrochemistry expertise.
H01G · Capacitors — electrode architecture and cell design
H01G (Capacitors) accounts for 47 patent records against C02F’s 383, a share of roughly 7% of the IPC-tagged corpus. CDI performance is directly governed by electrode capacitance, charge dynamics, and cell geometry, yet this branch remains thinly covered relative to process-level claims. Teams with supercapacitor or double-layer capacitor expertise could develop differentiated electrode architectures that are not blocked by existing C02F process patents. The US and South Korea are the most active prosecution venues, suggesting those markets as logical entry points.
Search this in Eureka →C01B · Non-metallic elements & inorganic compounds — advanced carbon media
C01B (Non-metallic elements & inorganic compounds) carries 27 patent records, a 4% share of the IPC-tagged corpus, and Lawrence Livermore’s secondary focus on C01B 32 confirms that advanced carbon materials (graphene, carbon nanotubes, activated carbon variants) are technically relevant but under-patented relative to the process layer. Realistic entry paths include hierarchical-pore carbon synthesis, doped-carbon electrodes, and bio-derived carbon precursors—areas where academic groups such as Changzhou University and Carnegie Mellon University have appeared in the corpus but have not yet built substantial portfolios.
Search this in Eureka →How leading filers differ by technology route
Route coverage across the main technology branches in the current evidence set.
| Player | C02F 1 · Water & wastewater treatment | C02F 103 · Water & wastewater treatment | B01D 61 · Separation processes (filtration etc.) | H01G 11 · Capacitors | C02F 101 · Water & wastewater treatment |
|---|---|---|---|---|---|
| Unilever NV | Strong · 33 | Moderate · 7 | Absent | Moderate · 8 | Moderate · 7 |
| Unilever PLC | Strong · 32 | Emerging · 5 | Absent | Moderate · 10 | Emerging · 5 |
| Doosan Heavy Industries & Construction Co Ltd | Strong · 21 | Moderate · 10 | Emerging · 3 | Absent | Emerging · 3 |
| Samsung Electronics Co Ltd | Strong · 23 | Absent | Absent | Absent | Absent |
| Lawrence Livermore National Security LLC | Strong · 18 | Absent | Absent | Absent | Emerging · 3 |
| Stockholm Water Technology AB | Strong · 14 | Moderate · 4 | Emerging · 2 | Absent | Absent |
| Siontech | Strong · 15 | Absent | Absent | Emerging · 2 | Absent |
Frequently asked questions
The corpus in scope comprises 194 patent families, with patent-record counts across jurisdictions and IPC branches exceeding that figure because a single family can be filed in multiple offices and tagged with multiple classifications.
Unilever NV leads with 31 patent records among the top-100 filers, followed by Unilever PLC (30 records) and Lawrence Livermore National Security LLC (26 records). When the two Unilever entities are treated as one corporate group, they collectively represent the dominant position in the field.
The field is in a Decline stage by the evidence’s lifecycle classification, with annual filings having eased from their 2018 peak of 40 patent records. The 2024–2026 data is subject to publication lag and should not be read as confirming further decline.
The United States leads with 109 patent records, followed by Europe (EPO) with 64, South Korea with 49, and WIPO (PCT) with 45. China (26 records) and India (19 records) are secondary markets reflecting growing domestic demand for brackish water treatment.
The most-cited work is titled ‘Method and apparatus for capacitive deionization’ with 368 citations, followed by multiple publications on ‘Alternating-polarity operation for complete regeneration’ (105, 46, 44, and 39 citations across related records) and ‘Polarized Electrode for Flow-through Capacitive Deionization’ (76 citations). These foundational references define the core CDI operating principles.
H01G (Capacitors, 47 patent records) and C01B (Non-metallic elements & inorganic compounds, 27 patent records) are the most technically proximate branches with relatively sparse coverage compared with the dominant C02F class. Both are directly relevant to CDI electrode design and advanced carbon media, and neither has yet attracted the dense filing density of the core process layer.
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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.
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