Capacitive Deionization Resource Recovery Patents: Leaders & Gaps 2026
- A small, recent field. 18 families total, filing peaked at 8 in 2023, and 2022 shows zero — momentum is uneven rather than building steadily.
- Metals and batteries claims overlap water treatment claims. C22B (metal extraction) and H01M (battery cells) each match C02F (water treatment) in record count, showing lithium recovery is being claimed from both sides.
- Receiving offices are split, not centralized. South Korea leads with 4 filings, but China, WIPO, Canada, Europe and the US each hold a handful — no single jurisdiction dominates yet.
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.
A niche where water treatment meets metal recovery
Capacitive deionization (CDI) resource recovery sits at the intersection of three established fields: water and wastewater treatment, metal extraction, and battery materials. The dataset behind this page — 18 patent families filed between 2015 and mid-2026 — reflects that overlap directly. Filings classified under C02F (water treatment) are matched almost one-for-one by filings under C22B (metal extraction) and H01M (batteries), meaning the same underlying electrode and cell architecture is being claimed from the water-treatment side and from the lithium-recovery side simultaneously.
That dual framing matters for anyone assessing freedom to operate: a search limited to water-treatment classifications alone would miss a meaningful share of the relevant prior art sitting in metals and battery classes. The technology is also young enough that publication lag — typically around 18 months between filing and publication — means the most recent filing year understates real activity.
Filing trend and technology composition
Two views of the same 18-family dataset: annual filing activity, and how those filings distribute across international patent classifications.
Filing trend, 2017–2026
Filings were absent in 2017 and flat through much of the decade, spiking to a peak of 8 in 2023 before falling back. The 2022 figure of zero shows this is not a smoothly growing field — it moves in short bursts tied to specific filers rather than sustained sector-wide investment.
IPC subclass distribution
C02F (water and wastewater treatment) leads with 13 records, but C22B (metal extraction) and H01M (batteries) each appear in 8 — roughly six in ten records touching water treatment also touch metals or battery chemistry. B01D (separation processes) and H01G (capacitors) round out the core cluster, while B09B (solid waste) and C01B (inorganic compounds) each appear only once, marking thin, largely unclaimed edges of the space.
Shares are the percentage of the 18 records in scope. A patent can carry several IPC classes, so the shares add up to more than 100%.
Go deeper on Capacitive Deionization Resource Recovery with Eureka
This page is one run against one query. Ask Eureka your own question about capacitive deionization resource recovery and every answer comes back with the patent numbers behind it.
Try EurekaThe records anchoring this space
Tunnel-structured ζ-V₂O₅ as a redox-active insertion host for hybrid capacitive deionization
Disclosed is a hybrid capacitive deionization cell (HCDI) that uses ζ-V2O5 as the positive electrode. Also disclosed are systems and methods for using an HCDI cell that uses ζ-V2O5 as the positive electrode for desalination of aqueous solutions and/or the recovery of ions such as lithium, potassium, and sodium.Filed by The Texas A&M University System, published July 2026 — one of the most recent records in the dataset.
| # | Publication no. | Patent title | Citations |
|---|---|---|---|
| 1 | CN116497232A | 连续化的阳离子交换膜/溶剂萃取/FCDI协同耦合的提锂方法 | 13 |
| 2 | WO2007087274A1 | Capacitive deionization using oscillatory fluid flow | 4 |
| 3 | CN120978254A | 电化学回收三元锂电池浸出液中锂离子的方法及系统 | 2 |
| 4 | CA2645482A1 | Capacitive deionization using oscillatory fluid flow | 2 |
| 5 | CN116730336A | 一种木质纤维炭的制备方法及其在沼液处理中的应用 | 1 |
| 6 | KR1020240083788A | Selective ion recovery device and method using flow electrode capacitive deionization | 1 |
Citation counts here are drawn from a corpus that favours older filings; a low count on a 2025 or 2026 record reflects age, not weak 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. Publication numbers are shown where the record carries one (6 of 6 rows); clicking a row searches Eureka by that number.
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Browse MCP servers →What the numbers say about this field
Three signals stand out once the filing trend, classification spread and citation pattern are read together.
Activity is bursty, not compounding
A flat midpoint followed by a single peak year points to a handful of filers moving at once rather than a broad wave of sector investment. Anyone tracking this space should watch specific assignees, not aggregate trend lines.
Lithium recovery claims sit in two worlds at once
Because C22B and H01M each nearly match C02F in record count, the same electrode chemistry is being claimed as a water-treatment innovation in one filing and a metal-recovery or battery-materials innovation in another.
One filing carries most of the citation weight
The most-cited record sits well above the rest of the table, which sat at 4 citations or fewer. That gap is typical of an early-stage field where a small number of foundational filings absorb most downstream citation.
Eureka can read the same corpus for gaps instead of for coverage: under-claimed branches adjacent to capacitive deionization resource recovery, with the prior art for and against each one.
Who is filing, and where they sit
With only 18 families in total and no assignee showing growth in the latest year, this is a field of small, distinct filer groups rather than an established competitive hierarchy.
University–national lab collaboration
The University of Minnesota's Board of Regents and Lawrence Livermore National Security jointly hold two families, suggesting a fundamental-research partnership rather than a commercialization push.
Battery-materials supply chain pairing
LG Energy Solution and Toray Advanced Materials Korea appear together on two families, pointing to a cell-maker and materials-supplier relationship built around electrode components for hybrid CDI.
No filer is currently accelerating
Every assignee with recent-year data shows zero filings in the latest tracked year, several down from prior activity. That is consistent with a field that spiked in 2023 and has not sustained the pace since.
| Assignee | Recent year | YoY |
|---|---|---|
| Texas A&M University System | 0 | -100% |
| Noble Materials Co., Ltd. | 0 | — |
| LG Energy Solution, Ltd. | 0 | -100% |
| Regents of the University of Minnesota | 0 | — |
| Lawrence Livermore National Security, LLC | 0 | — |
| Toray Advanced Materials Korea, Inc. | 0 | -100% |
| Korea Institute of Machinery and Materials | 0 | — |
| Korea Institute of Geoscience and Mineral Resources | 0 | — |
Where to take this
The dataset points to specific next steps depending on whether the goal is freedom-to-operate, sourcing, or R&D direction.
Search across classifications, not within one
Because lithium-recovery CDI claims split almost evenly across water-treatment, metals, and battery classes, a classification-limited search will undercount relevant prior art.
Run a cross-class searchTrack named filers directly
With filing activity concentrated in short bursts rather than a steady trend, monitoring specific assignees is more informative than watching the aggregate count.
Set up assignee monitoringRevisit the under-claimed branches
Thin classes like solid-waste nutrient recovery and non-metallic inorganic electrode chemistries carry only one or two records each — worth a closer look before assuming the space is occupied.
Explore white spaceCommon questions about this landscape
It refers to patent filings that combine capacitive deionization (CDI) or membrane CDI cell architectures with a recovery target such as lithium, nutrients, or other selectively extracted ions, rather than pure desalination. In this dataset that combination is captured by requiring both CDI-related terms in the title and recovery-related terms in the title or abstract. The IPC classification spread confirms the definition holds: filings sit across water treatment, metal extraction, and battery-related classes, reflecting that recovery-focused CDI is genuinely a hybrid category rather than a subset of conventional desalination patents.
The field has no single dominant filer; instead it shows several small clusters, including university-national lab pairings and battery-industry co-filings. Recent-year momentum data shows every tracked assignee at zero filings in the latest year, several down sharply from a prior peak, which means leadership in this space is better measured by who filed the foundational, most-cited records than by current filing volume. Anyone benchmarking competitors should treat the 2023 filing peak as the key reference point rather than the most recent year.
A jump like this in a small dataset usually reflects a handful of filers moving in the same short window rather than a sector-wide shift. With only 18 total families, a single active assignee filing several related applications can visibly move the annual count. It is also worth remembering that publication typically lags filing by around 18 months, so any apparent slowdown in the most recent year or two is at least partly an artefact of records not yet having published, not necessarily a real drop in activity.
C02F (water and wastewater treatment) is the largest class by record count, but C22B (metal extraction and refining) and H01M (batteries, cells and fuel cells) each appear in close to half the dataset, meaning a search confined to water-treatment codes alone would miss a substantial share of relevant claims. B01D (separation processes) and H01G (capacitors) also carry meaningful coverage. A thorough clearance search in this space needs to span all of these classes, not just the one that names the application most obviously.
The classes with only one or a few records — solid waste disposal (B09B) and non-metallic inorganic compounds (C01B) — show the thinnest coverage in this dataset, suggesting under-claimed sub-areas around digestate-based nutrient recovery and non-metallic ion-selective electrode chemistries. Oscillatory-flow cell design, despite appearing in some of the earliest and most-cited records, has not been heavily re-claimed since, which may leave room for newer variants. Any white-space assessment should be paired with a full-text claims review, since low record counts in a class can also mean a topic simply has not yet been discovered by filers rather than that it is legally open.
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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.