Lithium-Sulfur Battery Separator Patent Landscape
Lithium-Sulfur Battery Separator Patent Landscape in 2026
The lithium-sulfur battery separator space is highly concentrated, with Hon Hai Precision Industry and Tsinghua University collectively accounting for the majority of the top-ranked filers’ activity, anchored by a deep co-development relationship. Annual volume peaked in 2018 and has eased considerably since, placing the field in a post-peak phase where selective entrants and adjacent polymer and nanotechnology branches remain under-served.
Hon Hai and Tsinghua dominate a highly concentrated field
Hon Hai Precision Industry Co. Ltd leads the applicant ranking, followed by Tsinghua University in second place. Together with HRL Lab, Monash University, and Jiangsu Zenio New Energy Battery Technology, the top five filers account for 63% of the combined output of the hundred largest filers — an unusually high concentration for an advanced materials subfield.
The tier gap between the top two and the rest of the ranking is significant. No filer outside the top two approaches double-digit patent records, and the majority of ranked applicants hold three records or fewer, indicating a shallow competitive bench behind the two leaders.
| # | Applicant | Patent records | Share |
|---|---|---|---|
| 1 | Hon Hai Precision Industry Co. Ltd | 33 | |
| 2 | Tsinghua University | 24 | |
| 3 | HRL Laboratories LLC | 7 | |
| 4 | Monash University | 6 | |
| 5 | Jiangsu Zenio New Energy Battery Technology Co. Ltd | 4 | |
| 6 | LG Energy Solution Ltd | 3 | |
| 7 | Shanghai Research Institute of Petrochemical Technology, Sinopec | 3 | |
| 8 | Yangzhou University | 3 | |
| 9 | GM Global Technology Operations LLC | 3 | |
| 10 | CHINA PETROLEUM & CHEMICAL CORP | 3 |
| # | Applicant | Patent records | Share |
|---|---|---|---|
| 11 | Cornell University | 3 | |
| 12 | Tianjin Polytechnic University | 2 | |
| 13 | KING ABDULLAH UNIV OF SCI & TECH | 2 | |
| 14 | Korea Electrotechnology Research Institute | 2 | |
| 15 | Foxconn Technology (Shenzhen) Co. Ltd | 2 | |
| 16 | Jiangsu Pod New Material Co. Ltd | 2 | |
| 17 | Xiamen University | 1 | |
| 18 | Dalian Institute of Chemical Physics, Chinese Academy of Sciences | 1 | |
| 19 | Zhejiang Jincai New Material Co. Ltd | 1 | |
| 20 | Sun Yat-sen University | 1 |
Hon Hai’s position, reinforced by 22 co-filed records with Tsinghua University, suggests that much of the foundational separator IP in this space originates from a single collaborative program. Challengers seeking freedom to operate should examine the scope of that partnership’s claims carefully.
The most recent 18–24 months of filing data are subject to publication lag and likely under-represent actual recent activity; the apparent low volumes for 2024–2026 should not be read as absence of ongoing R&D. Longer-window growth, applicant concentration, and technology-route coverage are therefore more reliable signals than the latest-year bar alone.
Post-peak filing activity with a polymer and nanotechnology fringe
The annual filing trend and technology composition charts together reveal a field that peaked in 2018 and has contracted in annual volume, while the technology mix shows a dominant battery-cell core with a modest but technically meaningful fringe in nanotechnology and polymer chemistry.
Annual filing trend
Filings peaked at 25 records in 2018 and have eased substantially in subsequent years. The 2019 trough and the low volumes from 2022 onward are partly attributable to publication lag, particularly for 2024–2026, so the true recent pace is likely higher than the chart shows. The overall multi-year window nonetheless reflects a field that has moved past its primary filing surge.
↗ Hover for values · click a bar to ask EurekaTechnology composition
H01M (batteries, cells and fuel cells) accounts for the overwhelming majority of IPC classifications, confirming that separator work is framed almost entirely within battery-cell engineering. B82Y (nanotechnology applications) is the second-largest branch, followed by several polymer chemistry classes — C08G, C08F, C08J, and C08L — each with single-digit record counts, pointing to an emerging but sparse materials-science fringe.
↗ 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.
Lithium-sulfur battery separator
A lithium-sulfur battery includes a cathode, an anode, a lithium-sulfur battery separator and an electrolyte. The lithium-sulfur battery separator includes a pristine seperator (PSL) and a functional layer (FL). The FL is located on a surface of the PSL. The FL includes a plurality of graphene sheets and a plurality of MoP<sub>2 </sub>nanoparticles… (excerpt from the patent abstract)
| # | Patent | Citations |
|---|---|---|
| 1 | Lithium-based battery separator and method for mak… | 50 |
| 2 | Separators for lithium-sulfur batteries | 48 |
| 3 | Lithium-based battery separator and method for mak… | 29 |
| 4 | 一种锂硫电池隔膜及其制备方法和应用 | 19 |
| 5 | Lithium-sulfur battery separator and lithium-sulfu… | 15 |
| 6 | Lithium-sulfur battery | 12 |
| 7 | Gel electrolytes and the manufacture thereof | 11 |
| 8 | 一种石墨烯基多孔碳片材料、制备方法及其应用 | 11 |
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
Four structural observations — maturity, concentration, collaboration, and geography — define the investment case and the barriers a new entrant must navigate in lithium-sulfur battery separator IP.
Post-peak field with selective re-entry windows
The lifecycle stage is assessed as Decline, with annual filings easing back from the 2018 peak. This does not preclude new entry, but it does mean the low-hanging fruit of broad-claim filing has passed. Differentiated approaches — particularly in polymer membrane chemistry or nanostructured coatings — are more likely to yield defensible positions than incremental separator geometry work.
Lifecycle: DeclineTwo filers hold the commanding positions
The top five filers account for 63% of the hundred largest filers’ combined patent records, and the top two — Hon Hai Precision Industry and Tsinghua University — are structurally linked through co-development. Any entrant building a separator portfolio must assess freedom to operate against this concentrated core before committing resources to H01M-class claims.
Top-5 share: 63%A single dominant co-filing pair defines the ecosystem
The most active co-filing relationship is between Hon Hai Precision Industry (Foxconn) and Tsinghua University, with 22 jointly filed records — by far the largest collaboration count in the dataset. A secondary link exists between Tsinghua University and Foxconn Technology Group (2 records), and Sinopec’s Shanghai Petrochemical Research Institute co-filed once with China Petroleum & Chemical Corp. Outside these pairs, the collaboration network is sparse, suggesting limited open-innovation activity beyond the anchor partnership.
Co-filings: 22 (Hon Hai–Tsinghua)US-first filing with meaningful China and Taiwan presence
The United States is the leading jurisdiction by patent records, followed by China and Taiwan. Europe (EPO) and WIPO (PCT) together provide a significant international coverage layer. South Korea, India, Germany, Japan, and Australia each appear in the dataset, reflecting selective but not comprehensive global prosecution strategies. Entrants should note that Taiwan filings largely reflect Hon Hai’s home-jurisdiction strategy.
Lead office: United StatesGo 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 |
|---|---|---|
| Hon Hai Precision Industry Co. Ltd | Tsinghua University | 22 |
| Tsinghua University | Foxconn Technology Group Co. Ltd | 2 |
| Shanghai Research Institute of Petrochemical Technology, Sinopec | China Petroleum & Chemical Corporation (Sinopec) | 1 |
| LIU PING | HRL Laboratories LLC | 1 |
Co-filing pairs, ranked by the number of jointly-filed patent families.
Hon Hai and Tsinghua lead; new commercial entrants emerging
The top two filers are structurally linked and jointly define the H01M separator core. Below them, a new wave of commercially oriented entrants — particularly Jiangsu Zenio and Sinopec’s research arm — has entered recently, signaling a shift from academic-led to industry-led filing.
Hon Hai Precision Industry Co. Ltd
Hon Hai leads the ranking with 33 patent records, all concentrated in H01M battery and separator subclasses. The filing program was built in close collaboration with Tsinghua University (22 co-filed records), and the portfolio spans battery cell design (H01M 2, H01M 50) and lithium-ion / lithium-sulfur system engineering (H01M 10). No momentum trend is provided for Hon Hai in the recent-window data, indicating the bulk of its activity predates the most recent measurement period.
patent records: 33Jiangsu Zenio New Energy Battery Technology Co. Ltd
Jiangsu Zenio holds 4 patent records and is flagged as a new entrant in the recent filing window, making it one of the few commercially oriented Chinese battery manufacturers to have joined this space recently. Its technology focus spans H01M 10, H01M 50, and notably C08F addition polymers — suggesting a polymer-functionalized separator approach that distinguishes it from the purely electrochemical framing of the top two filers.
patent records: 4| Applicant | Recent (3 yrs) | Trend |
|---|---|---|
| Monash University | 1 | ▲ new entrant |
| Jiangsu Zenio New Energy Battery Technology Co. Ltd | 4 | ▲ new entrant |
| Shanghai Research Institute of Petrochemical Technology, Sinopec | 3 | ▲ new entrant |
Under-served branches in nanotechnology and polymer chemistry
Several IPC classes adjacent to the dominant H01M core have low record counts relative to their technical relevance to separator performance. These branches are observations of relative sparsity; two carry plausible entry paths for differentiated R&D.
B82Y · Nanotechnology applications
With 11 patent records and an 8% share among the branches observed, B82Y is the second-largest class in the dataset but remains sparse in absolute terms. Nanostructured separator coatings — including graphene-based porous carbon and nano-ceramic interlayers — appear in the most-cited records, suggesting technical value in polysulfide-shuttle suppression. The entry path is viable for materials-science labs with existing nanoparticle synthesis or 2D-materials capabilities, as the incumbent filers in this branch are not as concentrated as in H01M.
Search this in Eureka →C08G · Condensation polymers
C08G (condensation polymers) has only 6 patent records and a 4% share — notably sparse given that polysulfide-blocking functional membranes often rely on polyimide, polyamide, or other condensation-polymer backbones. Cornell University is the most prominent filer in this branch (C08G 77 silicone polymers). The low record count suggests most separator polymer work has not been claimed at the polymer-chemistry level, leaving room for composition-of-matter claims by entrants with polymer synthesis expertise.
Search this in Eureka →How leading filers differ by technology route
Strength of each leader across the main technology routes.
| Player | H01M 50 · Batteries, cells & fuel cells | H01M 10 · Batteries, cells & fuel cells | H01M 2 · Batteries, cells & fuel cells | H01M 4 · Batteries, cells & fuel cells | B82Y 30 · Nanotechnology applications |
|---|---|---|---|---|---|
| Hon Hai Precision Industry Co. Ltd | Strong · 33 | Strong · 26 | Strong · 33 | Moderate · 13 | Emerging · 5 |
| Tsinghua University | Strong · 24 | Strong · 22 | Strong · 24 | Moderate · 12 | Moderate · 6 |
| Monash University | Strong · 6 | Strong · 6 | Absent | Absent | Emerging · 1 |
| HRL Laboratories LLC | Strong · 5 | Absent | Strong · 4 | Absent | Absent |
| Jiangsu Zenio New Energy Battery Technology Co. Ltd | Strong · 4 | Strong · 4 | Absent | Absent | Absent |
| HICKS GARNER JOCELYN | Strong · 3 | Absent | Strong · 3 | Absent | Absent |
Frequently asked questions
The evidence set contains 78 patent families in scope for this technology topic.
Hon Hai Precision Industry Co. Ltd leads with 33 patent records, followed by Tsinghua University with 24 patent records. The two organizations are co-filers on 22 of those records.
Annual filings peaked in 2018 at 25 records and have eased substantially since. The lifecycle assessment classifies the field as post-peak. The most recent 18–24 months are subject to publication lag, so very recent volumes may be understated.
The United States leads by patent records, followed by China and Taiwan. Europe (EPO) and WIPO (PCT) provide the main international coverage layer. Taiwan’s prominence reflects Hon Hai’s home-jurisdiction filing strategy.
Yes. B82Y (nanotechnology applications, 11 records) and C08G (condensation polymers, 6 records) are the most technically relevant sparse branches. Both have plausible entry paths for labs with nanomaterials or polymer synthesis capabilities, and neither is dominated by the same concentrated pair that leads the H01M core.
Applicant momentum data flags Monash University, Jiangsu Zenio New Energy Battery Technology Co. Ltd, and the Shanghai Research Institute of Petrochemical Technology (Sinopec) as new entrants in the recent filing window, each bringing commercially or industrially oriented perspectives to separator development.
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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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