Prussian Blue Analogue Cathode Patents: Top Companies & Trends 2026
- Filing peaked in 2023 at 27 families, then eased back toward the 2022 level — this is a maturing filing wave, not one still accelerating.
- China accounts for 87 of the tracked filings, against single digits from the US, Europe, Korea and India combined, so most claim scope sits under Chinese examination practice.
- Momentum has gone flat at the top, with several previously active assignees showing zero filings in the latest year and one falling -100% YoY.
Filing growth compares 2021 (5 records) with 2024 (22) — 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 114 records in scope (CR5), not by the ranked leaders only.
What the filing record shows
Prussian blue analogue (PBA) cathodes — nickel hexacyanoferrate and related hexacyanoferrate chemistries — sit at the intersection of sodium-ion battery development and low-cost, cobalt-free cathode design. The dataset tracks 114 patent families filed between 2015 and the 2026 cut-off, concentrated in claims touching vacancy defects, crystal water content, coprecipitation synthesis, rate capability and structural stability. Filing activity was negligible before 2017, built steadily through the early 2020s, and peaked in 2023 at 27 families before the midpoint-to-latest-year trend turned flat or declining.
Because publication typically lags filing by around 18 months, the apparent slowdown in the most recent year is partly an artefact of the data cut-off rather than a confirmed drop in activity. Even so, the shape of the curve — a sharp climb followed by a plateau — points to a technology area where the core coprecipitation and defect-control claims are now well populated, and where new entrants need to differentiate rather than restate.
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Filing trend and technology composition
The two views below separate when filings happened from what they actually claim, which matters for a chemistry that spans battery, cyanide-compound and nanotechnology classifications.
Annual filing trend
Filings rose from zero in 2017 to a peak of 27 in 2023, with 2022 sitting at the midpoint of 13 — the growth phase has flattened rather than continued to accelerate into the most recent, still-incomplete year.
IPC subclass distribution
H01M (batteries, cells & fuel cells) dominates at 108 of 114 records, with C01C (cyanides and nitrogen compounds) a distant but substantial second at 67, confirming that most filings are battery-application claims built on hexacyanoferrate chemistry rather than pure inorganic-chemistry claims. Smaller pockets in B82Y (nanotechnology), C01B, C01G, H01G, C02F and C23C mark adjacent framing — particle-scale morphology, capacitor use and coating routes — that sit outside the core battery claim set.
Shares are the percentage of the 114 records in scope. A patent can carry several IPC classes, so the shares add up to more than 100%.
Go deeper on Prussian Blue Analogue Cathode Materials with Eureka
This page is one run against one query. Ask Eureka your own question about prussian blue analogue cathode materials and every answer comes back with the patent numbers behind it.
Try EurekaRepresentative and most-cited filings
WO2024168546A1 — Prussian blue-analogue nanoscale cathode material and preparation method
The filing claims a Prussian blue analogue nanoscale cathode material with general formula NaxMy[Fe(CN)6]z, where M is a transition metal and 0<x<2, 0<y<1, 0<z<1, produced as particles with diameter below 60nm for use in sodium-ion batteries. The application states the sub-60nm particle scale improves sodium diffusion rate, sodium storage capacity and rate performance, and describes a preparation method claimed to give high yield suitable for industrial-scale production.Filed by Shenzhen Institutes of Advanced Technology, published 2024-08-22.
| # | Publication no. | Patent title | Citations |
|---|---|---|---|
| 1 | US20140220392A1 | Prussian Blue Analogue Anodes for Aqueous Electrolyte Batteries | 44 |
| 2 | US20140127560A1 | Stabilization of battery electrodes using prussian blue analogue coatings | 33 |
| 3 | CN105990567A | 一种类普鲁士蓝纳米材料的制备方法及其在钠离子电池中的应用 | 24 |
| 4 | US20140127592A1 | Stabilization of battery electrodes using polymer coatings | 21 |
| 5 | CN115207316A | 一种普鲁士蓝类似物正极材料的制备方法及应用 | 17 |
| 6 | CN110767906A | 一类基于吩嗪负极材料的可充水系离子电池及其制备方法 | 15 |
| 7 | CN112694104A | 一种普鲁士蓝类似物及其制备方法、负极材料和应用 | 13 |
| 8 | CN114620758A | 一种氧化铜修饰铁基普鲁士蓝正极材料的制备方法 | 11 |
| 9 | CN110391407A | 一种核壳结构的动力电池正极材料及其制备方法和用途 | 11 |
| 10 | WO2024168546A1 | 一种类普鲁士蓝纳米正极材料及其制备方法和钠离子电池 | 8 |
Citation counts accumulate over time and favour older US filings in this corpus; treat them as a measure of historical influence on the field, not of which claims are most relevant to file around today.
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.
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Three patterns in the data matter more than the raw counts: where claims concentrate, how citation weight is distributed, and what the co-filing map says about how this space is organised.
Battery-application claims dominate
Almost every record in this dataset is framed as a battery-application claim rather than a standalone inorganic-chemistry claim, and 67 records also carry a C01C cyanide-compound classification — meaning most filers are claiming the hexacyanoferrate chemistry and its battery use together, not separately.
Filing scope concentrates in one office
China's receiving-office count dwarfs WIPO, US, EPO, India and Korea combined, which means the enforceable claim language most filers actually rely on has been shaped and examined under Chinese practice rather than under US or EPO precedent.
Activity has gone quiet at the top
Several assignees that filed in prior years — including one with a full year-on-year drop — show zero filings in the latest tracked year. Combined with the post-2023 plateau in the trend line, this points to a first filing wave that has largely run its course rather than one still building.
Citation weight sits with early US filings
The most-cited records in this corpus are older US applications from the mid-2010s; more recent Chinese filings, including the highly specific sodium-ion cathode claims from 2022 onward, have not yet accumulated comparable citation counts simply because they are younger.
Eureka can read the same corpus for gaps instead of for coverage: under-claimed branches adjacent to prussian blue analogue cathode materials, with the prior art for and against each one.
Who is filing, and where the gaps sit
The assignee set includes established battery manufacturers, university labs and specialist sodium-ion startups, with only two documented co-assignee pairs — suggesting most work here is still done in-house rather than through joint filing.
Sodium-ion specialists filing in narrow pairs
Northvolt and Altris appear as a co-assignee pair, alongside a university-institute pairing between Zhengzhou University and a Wuhan marine-propulsion research institute — evidence of a small number of targeted collaborations rather than a broad partnership network.
No assignee is currently scaling filings
The most active assignees in the latest tracked year — a Liaoning sodium-battery specialist and Zhengzhou University — each show only a single filing, and one of those is down 50% year-on-year. No assignee in this dataset is currently increasing its filing rate.
Larger names have paused rather than withdrawn
Northvolt, CATL and Wuyi University all show zero filings in the latest year despite earlier activity. Given the ~18-month publication lag, this may understate work already filed but not yet published rather than confirm a strategic exit.
| Assignee | Recent year | YoY |
|---|---|---|
| Liaoning Xingkong Sodium Battery Co., Ltd. | 1 | -50% |
| Zhengzhou University | 1 | — |
| Aierwei'ou Energy Co., Ltd. | 0 | — |
| Northvolt | 0 | -100% |
| Contemporary Amperex Technology Co., Ltd. (CATL) | 0 | — |
| Wuyi University | 0 | — |
| Hongxing (Shanxi) New Energy Materials Co., Ltd. | 0 | — |
| Wenzhou Nashu New Energy Technology Co., Ltd. | 0 | — |
Where to take this
The filing plateau and China-concentrated scope mean the next moves are about precision — checking specific claim language and adjacent branches — rather than a broad landscape re-scan.
Check freedom-to-operate on defect and water-content claims
Vacancy-defect control and crystal-water management are the two technical-detail search terms that pull this dataset together; run a targeted claim-scope check on both before committing to a coprecipitation process design.
Run a claim search in EurekaTrack the assignees that have gone quiet
Several previously active filers show zero activity in the latest year; given publication lag, monitor them for filings that may surface over the next 12-18 months rather than assuming they have exited.
Set up assignee monitoring in EurekaMap the capacitor and coating overlaps
Small but real filing counts in H01G and C23C suggest PBA chemistry is being explored outside the core battery-cathode use case; a focused search there may surface less-crowded claim space.
Explore adjacent IPC classes in EurekaCommon questions on this landscape
Prussian blue analogue (PBA) cathodes, built on nickel hexacyanoferrate and related hexacyanoferrate frameworks, are used mainly in sodium-ion batteries as a lower-cost, cobalt-free alternative to layered oxide cathodes. Their open framework structure allows sodium ions to move in and out during charge and discharge, which is central to the rate-capability claims that dominate this patent dataset. They are also explored in capacitor and water-treatment contexts, though those represent a small share of the filings tracked here (H01G and C02F together account for single-digit record counts).
The dataset shows a mix of Chinese universities, specialist sodium-ion battery makers and a small number of international names, with no single assignee showing sustained year-on-year growth in the most recent period. Filing activity is spread across many single-digit filers rather than concentrated at a dominant leader, which is consistent with a technology still being worked out at the process-engineering level rather than owned by one company. Recent-year momentum data suggests most previously active filers, including larger battery manufacturers, have slowed rather than accelerated.
Filings climbed from essentially zero in 2017 to a peak of 27 families in 2023, tracking the broader surge of interest in sodium-ion batteries as a cheaper alternative to lithium-ion chemistries during that period. The subsequent flattening does not necessarily mean interest has dropped: patent publication lags filing by roughly 18 months, so filings made in 2024 and 2025 may not be fully visible in this dataset yet. What the plateau does indicate is that the initial wave of foundational coprecipitation and defect-control claims has largely been staked out.
The core battery-application claims under H01M are heavily populated, but adjacent framings are thinner: capacitor-format hexacyanoferrate electrodes, wastewater-derived precursor routes, and surface-coating deposition methods each show only single-digit record counts in this dataset. Vacancy-defect quantification and crystal-water control are searched heavily as claim terms but the specific measurement and process-control methods within them are not uniformly covered. Anyone considering these branches should still run a targeted freedom-to-operate search, since low density is not the same as an open field.
Yes — of the receiving offices tracked, China accounts for 87 filings versus single-digit counts each for WIPO/PCT, the United States, Europe, India and South Korea. This means the enforceable claim scope most filers rely on has largely been examined under Chinese patent practice, and companies planning to compete in this space outside China should check separately whether equivalent protection exists, or is absent, in their target jurisdictions.
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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.