Sodium-Ion Hard Carbon Anode Patents: Top Companies & Trends 2026
Filing growth compares 2021 (13 records) with 2024 (46) — 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 409 records in scope (CR5), not by the ranked leaders only.
What this landscape covers
This review covers 409 published patent records filed or published between 2015 and mid-2026 that combine hard carbon anode terminology with the core sodium-ion battery classification H01M10/054. It captures the material preparation routes, cell architectures and precursor chemistries that assignees have chosen to claim around hard carbon as the dominant anode material for sodium-ion cells, rather than the broader sodium-ion field as a whole.
Publication lags filing by roughly 18 months, so the 2025 and 2026 counts in the trend chart understate real filing activity for those years and should not be read as a slowdown.
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Filing trend and technology composition
Two views of the same 409-record dataset: how filing activity has moved year over year, and which IPC subclasses the records fall into.
Filing activity climbed sharply into 2024
Annual filings peaked at 56 in 2017, cooled, then rebuilt momentum through the early 2020s: 2021 to 2024 alone saw a 254% rise, from 13 to 46 records. The 2025-2026 dip reflects publication lag rather than a real drop in filing.
Concentration in core battery claims, with a secondary chemistry cluster
Every record sits in H01M by construction of the search. Beyond that, 14.7% of records also carry a C01B non-metallic compound classification, and smaller overlaps appear in capacitors (H01G, 5.9%), nanotechnology (B82Y, 2.2%) and other metal compounds (C01G, 2.0%) — signalling where hard carbon anode work borders precursor synthesis and complementary storage formats.
Shares are the percentage of the 409 records in scope. A patent can carry several IPC classes, so the shares add up to more than 100%.
Go deeper on Sodium-Ion Batteries: Hard Carbon Anode Patent Landscape with Eureka
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Try EurekaMost-cited records and a representative recent filing
Preparation method of hard carbon anode material and use thereof (US20240088388A1)
The disclosure belongs to the technical field of sodium ion battery materials, and discloses a preparation method of a hard carbon anode material and use thereof. The preparation method includes performing first sintering on starch, crushing, and introducing air and nitrogen for secondary sintering to obtain porous hard block granules; and performing third sintering on the porous hard block granules, then continuously warming up to perform fourth sintering to obtain the hard carbon anode material. The resulting material has a reversible capacity of no less than 330 mAh/g, with strong cycle stability and initial coulomb efficiency.Filed by Guangdong Brunp Recycling Technology, dated 2024-03-14 — a multi-stage starch sintering route rather than a single-step carbonisation, which is where much of the recent claim activity in this space concentrates.
| # | Publication no. | Patent title | Citations |
|---|---|---|---|
| 1 | US20160301096A1 | Zinc Ion-Exchanging Energy Storage Device | 170 |
| 2 | US20120164499A1 | Stationary, fluid redox electrode | 164 |
| 3 | US20160344035A1 | Alkali Metal Secondary Battery Containing a Carbon Matrix- or Carbon Matrix Composite-based Dendrite-Intercep… | 162 |
| 4 | US20170104204A1 | Continuous process for producing electrodes and alkali metal batteries having ultra-high energy densities | 135 |
| 5 | WO2012024499A1 | Stationary, fluid redox electrode | 127 |
| 6 | US20170077546A1 | Alkali metal or Alkali-Ion batteries having high volumetric and gravimetric energy densities | 115 |
| 7 | US20130302697A1 | Rechargeable magnesium-ion cell having a high-capacity cathode | 115 |
| 8 | US20170207484A1 | Alkali Metal-Sulfur Batteries Having High Volumetric and Gravimetric Energy Densities | 114 |
| 9 | US6872492B2 | Sodium ion batteries | 112 |
| 10 | US20160294000A1 | Active cathode layer for metal-sulfur secondary battery | 107 |
Citation counts accumulate over time, so older records are structurally favoured; treat this table as a map of influential prior art, not of current filing activity.
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Four read-outs from the dataset that matter more for decision-making than the raw counts alone.
Leadership is concentrated but not closed
The top 5 assignees account for 41.3% of all 409 records, and the top 10 for 51.3%. That leaves roughly half the field spread across a ranked list of 100 companies, most holding only a handful of filings each — evidence of an active long tail rather than a settled oligopoly.
Recent growth is the fastest in the dataset's history
Filings rose from 13 in 2021 to 46 in 2024, a faster three-year climb than the run-up to the 2017 peak of 56. Because publication lag suppresses 2025-2026 counts, this growth trend is the most reliable recent signal available.
Precursor chemistry is the busiest neighbouring claim space
Beyond the core H01M battery classification that covers every record by design, C01B non-metallic compound chemistry appears in 14.7% of the 409 records — well ahead of capacitors (5.9%) or nanotechnology applications (2.2%). Precursor and dopant synthesis claims are where hard carbon work most often crosses into other art.
A small number of inventor pairs dominate joint filings
Only 10 co-assignee pairs appear across the dataset, and the strongest single pair accounts for 28 shared records — far ahead of the next pairs. Co-filing is rare overall, which means most claim territory here was built by individual assignees working alone rather than through joint development.
Eureka can read the same corpus for gaps instead of for coverage: under-claimed branches adjacent to sodium-ion batteries: hard carbon anode patent landscape, with the prior art for and against each one.
Where to take this analysis
The dataset points to specific next steps depending on whether the goal is freedom-to-operate, competitive tracking or white-space filing.
Map claims against the top-cited prior art
The five most-cited records in this dataset carry citation counts from 127 up to 170 and define much of the foundational claim territory around alkali-metal anode structures. Any new filing in this space should be checked against these before drafting.
Explore citation trees in EurekaTrack the fast-growing filer segment
With filings up 254% from 2021 to 2024, the assignees behind that growth are worth monitoring for filing cadence and geographic spread rather than just cumulative counts.
Set up assignee tracking in EurekaScope the precursor-chemistry overlap
The 14.7% overlap with C01B suggests real opportunity in precursor and dopant claims adjacent to the core anode material. A targeted search combining both classes would sharpen the freedom-to-operate picture.
Run a cross-class search in EurekaCommon questions about sodium-ion hard carbon anode patents
The dataset ranks 100 assignees by record count, and the leader holds 106 of the 409 records in scope, well ahead of the field. The top 5 assignees combined account for 41.3% of all records, and the top 10 account for 51.3%, so leadership is concentrated at the very top but the remaining half of the field is spread thinly across dozens of smaller filers. This mix of a dominant leader and a long tail is typical of a technology that is commercially active but not yet consolidated.
Filings rose from 13 records in 2021 to 46 in 2024, a 254% increase over three years, and 2017 remains the single highest year on record with 56 filings. The 2025 and 2026 figures in the raw trend look lower, but that is a publication-lag artefact: patents typically publish about 18 months after filing, so the most recent one to two years are always undercounted at the time of any snapshot. Read the 2021-2024 window as the most trustworthy recent signal of momentum.
Every record in this dataset sits in the core battery classification H01M by construction of the search, but 14.7% of the 409 records also carry a C01B classification covering non-metallic elements and inorganic compounds — largely precursor and dopant chemistry work. Smaller overlaps exist with capacitors (5.9%), nanotechnology applications (2.2%) and other metal compounds (2.0%). These overlaps mark where hard carbon anode claims border adjacent art rather than standing alone.
High filing density in the core battery class does not mean every angle is claimed; it means claim space around the base anode structure is occupied. With 100 ranked assignees but only the top 10 holding just over half of all records, and adjacent classes like C01B, B82Y and C01G showing much lower filing density, precursor synthesis routes and cross-format applications look comparatively under-claimed relative to the core material claims. A freedom-to-operate search focused on those adjacent classes is likely to surface more open territory than a search on H01M alone.
The most-cited record in this dataset is a zinc ion-exchanging energy storage device patent cited 170 times, followed closely by records on fluid redox electrodes and carbon-matrix dendrite-intercepting layers cited in the 160s. High citation counts favour older patents simply because they have had more time to accumulate citations within a searched corpus, so treat this list as a map of influential foundational art rather than a signal of which technology is currently most active or valuable.
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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.