SEI Engineering Technology Landscape 2026 — PatSnap Eureka
Solid Electrolyte Interphase Engineering: Patent Landscape 2026
SEI engineering governs cycling stability, safety, and energy density in next-generation lithium batteries. This landscape maps the key assignees, technology clusters, and strategic IP whitespace across 25+ years of patent activity — from foundational polymer electrolytes to plasma-assisted synthesis.
Three Interconnected Sub-Domains Define the SEI Engineering Landscape
Solid electrolyte interphase (SEI) engineering sits at the intersection of electrochemistry, materials science, and manufacturing science. As documented by WIPO and leading battery research bodies, the SEI layer governs cycling stability, safety, and energy density — making its deliberate design the central challenge of next-generation battery development.
The dataset spans filing dates from 2000 to 2026, with notable concentration of activity from 2019 onward. The field is best understood through three interconnected sub-domains: solid electrolyte materials (the bulk ionic conductors — polymer, inorganic ceramic, and composite hybrid), interface and interphase engineering (deliberate manipulation of the electrode–electrolyte contact zone, including pre-formed SEI layers and in-situ polymerization strategies), and electrode surface chemistry (modification of anode surfaces, especially silicon and lithium metal, to suppress dendrite growth and reduce interfacial resistance).
The single most directly SEI-relevant patent in this dataset — filed by OLA Electric Mobility Private Limited (IN, 2022) — describes an engineered SEI consisting of a porous polymer matrix of an electrically conducting polymer embedded with a mixture of metal precursors, including a heteroatom metal precursor, applied directly to the current collector. This represents the core paradigm of the field: pre-engineered, compositionally controlled SEI layers rather than relying on spontaneous film formation. Teams using PatSnap's IP analytics platform can map this paradigm shift across the full patent corpus.
Assignees span China (dominant), South Korea, Japan, and Western Europe, with China's research universities and industry players accounting for the largest share of recent filings. The U.S. Department of Energy and equivalent bodies in Europe have highlighted solid-state battery interfaces as a priority research area, aligning with the patent signals observed here.
SEI Engineering by the Numbers
Key quantitative signals extracted from the PatSnap Eureka patent dataset, covering jurisdiction distribution, ionic conductivity performance, and technology maturity.
Patent Jurisdiction Distribution — SEI Engineering Dataset
China dominates with ~30 CN-jurisdiction filings; KR and JP follow, with IN notable for the only dedicated SEI pre-formation patent.
Ionic Conductivity Performance — Representative SEI Electrolytes
Peking University's PET dual-crosslinked poly(ionic liquid) achieves 1.0–1.5 mS/cm with a 5–6 V electrochemical window (2025).
SEI Engineering Filing Activity Timeline (2000–2026)
Activity concentrates sharply from 2019 onward, with 2023–2026 filings the most numerous — signalling rapid field diversification.
Electrochemical Window — Key SEI Electrolyte Architectures
Peking University's dual-crosslinked poly(ionic liquid) achieves a 5–6 V electrochemical window, critical for high-voltage cathode compatibility.
Four Core Approaches to SEI Engineering
The patent dataset organises into four distinct technical clusters, each addressing the electrode–electrolyte interphase challenge from a different materials and process angle.
Crosslinked Polymer Network Electrolytes
The largest cluster in this dataset. These approaches replace linear or semi-crystalline polymer matrices with three-dimensional covalent networks to reduce crystallinity, suppress PEO's known ionic conductivity limitations below 60°C, and improve mechanical strength against lithium dendrite penetration. Peking University's 2025 PET-reinforced dual-crosslinked poly(ionic liquid) achieves ionic conductivity of 1.0–1.5 mS/cm and an electrochemical window of 5–6 V. Southwest Jiaotong University's hollow MOF crosslinking approach (2024) creates 3D lithium-ion conduction channels using amino-functionalized hollow MOF as a multi-site covalent crosslinking node.
1.0–1.5 mS/cm · 5–6 V windowInorganic/Ceramic Composite and Hybrid Electrolytes
These approaches blend or laminate inorganic ceramic conductors — NASICON-type LATP, garnet-type LLZTO, LLZO, zirconia — with polymer matrices to achieve the mechanical ductility of polymers with the ionic conductivity of ceramics, while simultaneously engineering a controlled interface. Shanghai Jiao Tong University's 2024 patent achieves 70–90 wt% NASICON ceramic loading in polymer binder with silane coupling agent. Zhejiang University of Technology's 2026 plasma approach simultaneously removes organic solvent residues and achieves in-situ PEO crosslinking with uniformly dispersed LLZTO filler.
70–90 wt% ceramic loadingArtificial SEI and Electrode Interface Layers
The most directly SEI-focused cluster. These patents address the pre-engineering of the electrode–electrolyte interphase, rather than relying on spontaneous SEI formation from electrolyte decomposition products. OLA Electric Mobility's 2022 patent describes a porous conducting polymer matrix embedding mixed metal precursors applied to the current collector to prevent dendrite formation — described as simple, cost-effective, and scalable. IBM's bilayer interface on silicon anodes (KR, 2023/2025) creates a thin semi-dielectric LiF layer adhered to the electrode surface, paired with a molten-ion-conducting lithium salt layer, reducing energy loss and heat. This cluster represents a major IP whitespace given that only one patent directly addresses pre-engineered SEI composition as a standalone technology.
Major IP whitespace identifiedIonic Liquid and Quasi-Solid Electrolyte Architectures
Ionic liquid-based approaches maintain high ionic conductivity while reducing volatility and flammability, often combined with polymer hosts for film-forming capability. Beijing Institute of Technology's porous silica network (JP, 2020) suppresses lithium deposition and shows low and stable interfacial impedance with lithium metal. Shaanxi University of Science and Technology's 2025 imidazolium-based poly(ionic liquid) in PVDF-HFP matrix retains a micro-liquid phase within the solid matrix, combining low interfacial resistance of liquids with mechanical stability of solids. Dankook University's 2025 triazolium ionic liquid monomer is in-situ polymerized without organic solvent, achieving enhanced ionic conductivity and high-temperature and high-voltage stability.
Solvent-free · low interfacial resistanceTop SEI Engineering Assignees by Filing Volume and Relevance
Innovation is moderately concentrated — LG Energy Solution leads industrially, but the majority of technically novel approaches originate from Chinese and Korean academic institutions.
| Assignee | Jurisdiction | Focus Area | Notable Filing |
|---|---|---|---|
| LG Energy Solution / LG Chem | KR / JP | Polymer solid electrolytes, all-solid-state battery manufacturing | Freeze-thaw crosslinking; laminate manufacturing (JP, 2025/2026) |
| Beijing Institute of Technology | CN | Ionic liquid electrolytes, alkali-ion batteries, SEI detection | CLSM dendrite detection; hyper-crosslinked polymer for Na-ion (2025) |
| Harbin Institute of Technology | CN | Composite electrolyte films, in-situ polymerization | 500-hour lithium cycling stability (CN, 2022) |
| International Business Machines Corporation | KR | Artificial SEI / silicon anode interface engineering | Bilayer LiF/lithium-salt interface on silicon anode (KR, 2023/2025) |
| OLA Electric Mobility | IN | Engineered SEI for current collectors | Only dedicated SEI pre-formation patent in dataset (IN, 2022) |
| Huazhong University of Science & Technology | CN | Wide-temperature-range electrolytes, flame-retardant electrolytes | Broad temperature operation; flame retardant polymer systems |
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Five Signals Defining the Next Cycle of SEI Innovation
Based on the most recent filings in this dataset, four distinct directions are visible — plus a fifth manufacturing-scale signal from LG Energy Solution.
Plasma-Assisted and Solvent-Free Electrolyte Synthesis
Zhejiang University of Technology's plasma-assisted PEO/LLZTO composite (CN, 2026) is the earliest plasma-processing approach in this dataset. By simultaneously removing organic solvent residues and crosslinking PEO at low temperature, it addresses two persistent manufacturing barriers: solvent residue contamination of the SEI and filler agglomeration. Process IP in solvent-free electrolyte manufacturing is sparse and strategically valuable.
SEI Visualization and Diagnostic Methods
Beijing Institute of Technology (CN, 2025) uses confocal laser scanning microscopy (CLSM) on fluorescent electrolytes — NASICON doped with Eu³⁺, Tb³⁺, Sm³⁺ — to map dendrite distribution post-cycling. This is a direct analytical tool for SEI/electrolyte interphase characterization at the inorganic solid electrolyte interface, targeting both sodium and lithium solid-state batteries.
Multi-Layer Gradient Electrolyte Architectures for Fast Charging
Zhejiang University (CN, 2025) introduces deliberate functional asymmetry into the electrolyte layer — a high-conductivity core sandwiched between high critical-current-density outer layers. This is directly relevant to SEI engineering as the outer layers control the interface kinetics with the anode and cathode, addressing the fast-charging challenge for next-generation EV batteries.
Cationic Polymer Electrolytes for Lithium Transference Control
Anhui Huaqi Environmental Protection Technology (CN, 2025) and Beijing Institute of Technology (CN, 2025) both engineer the ionic transport environment to push lithium transference numbers higher, reducing concentration polarization at the electrode–electrolyte interface — a key SEI stability factor. The Beijing IT patent explicitly covers sodium and other alkali ions, signalling expansion beyond lithium.
From EV Packs to Flexible Wearables: Where SEI Engineering Is Deployed
The most cited application context across the dataset is electric vehicles and grid storage. All-solid-state battery patents from Honda Motor Company (JP, 2025) and General Motors (CN, 2025) explicitly target EV battery packs, with the GM patent covering sintered oxide solid electrolyte integration into electrode composites. As tracked by the International Energy Agency, solid-state battery deployment in EVs remains the highest-value commercial target for SEI engineering advances.
Lithium metal batteries represent a dominant application target in the 2023–2026 filings. The SEI engineering challenge for lithium metal anodes — dendrite suppression, volume change accommodation, stable interface maintenance — is explicitly addressed by OLA Electric (IN, 2022), IBM (KR, 2023/2025), Celgard (JP, 2021), and multiple Chinese university assignees. Harbin Institute of Technology's composite electrolyte film reports 500-hour lithium cycling stability.
Flexible and wearable electronics are referenced in several patents. The polycaprolactone-based electrolyte from South China University of Technology (CN, 2021) explicitly references flexible all-solid-state lithium metal batteries and wearable electronics. Georgia Tech Research Corporation's elastomeric electrolyte (CN, 2024) targets deformable energy storage devices with mechanical compliance. PatSnap's life sciences and advanced materials solutions can help teams track these cross-domain applications.
An emerging signal for sodium-ion and multi-ion batteries appears in Beijing Institute of Technology's hyper-crosslinked polymer electrolyte (CN, 2025), which explicitly covers sodium and other alkali ions. The SEI detection method from Beijing Institute of Technology (CN, 2025) targets both sodium and lithium solid-state batteries, signalling broadening applicability beyond lithium-only chemistries. Teams monitoring this space can leverage PatSnap's analytics tools to track cross-chemistry filing trends.
Supercapacitors also feature: Shandong University of Technology's PolyAS electrolyte-based supercapacitor (CN, 2022) demonstrates crosslinked polymer electrolytes functioning as supercapacitor separators operational to −70°C, broadening the applicability of SEI-relevant polymer architectures well beyond battery applications.
Solid Electrolyte Interphase Engineering — Key Questions Answered
SEI engineering encompasses the deliberate design, formation, and control of the nanoscale interfacial layer that forms between electrodes and electrolytes in lithium-based batteries — a layer that governs cycling stability, safety, and energy density.
China is the dominant jurisdiction with approximately 30 of the most directly relevant filings originating from CN-jurisdiction patents. The KR jurisdiction is second, primarily through LG Energy Solution/LG Chem and Samsung SDI. JP jurisdiction filings are primarily PCT/Korean-origin applications filed by LG Energy Solution in Japan, plus Honda Motor Company and Sony Corporation.
The field is organised into four main clusters: (1) Crosslinked Polymer Network Electrolytes — the largest cluster, replacing linear polymer matrices with 3D covalent networks; (2) Inorganic/Ceramic Composite and Hybrid Electrolytes blending ceramics with polymer matrices; (3) Artificial SEI and Electrode Interface Layers addressing pre-engineered electrode–electrolyte interphase; (4) Ionic Liquid and Quasi-Solid Electrolyte Architectures maintaining high ionic conductivity while reducing volatility and flammability.
Top assignees by filing volume and relevance include LG Energy Solution / LG Chem (KR/JP), Beijing Institute of Technology (CN), Harbin Institute of Technology (CN), Huazhong University of Science and Technology (CN), Forschungszentrum Julich (CN), International Business Machines Corporation (KR), OLA Electric Mobility (IN), and Georgia Tech Research Corporation (CN).
Four distinct emerging directions are visible in 2024–2026 filings: (1) Plasma-assisted and solvent-free electrolyte synthesis; (2) SEI visualization and diagnostic methods using confocal laser scanning microscopy; (3) Multi-layer gradient electrolyte architectures for fast charging; (4) Cationic polymer electrolytes for lithium transference control. A fifth direction — polymer solid electrolyte laminates for continuous manufacturing — signals the transition from laboratory-scale to production-scale.
The SEI formation mechanism remains the single most critical unresolved interface challenge. Only one patent (OLA Electric, IN, 2022) directly addresses pre-engineered SEI composition as a standalone technology. Silicon anode SEI engineering is also underdeveloped — IBM's bilayer LiF/lithium-salt interface architecture on silicon anodes is one of very few patents addressing the silicon anode–electrolyte interface specifically, representing a high-leverage IP investment area with limited current competition.
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References
- Solid Electrolyte Interphase (SEI) and a Method for Its Preparation — OLA Electric Mobility Private Limited, 2022, IN
- Low-Resistance Composite Silicon-Based Electrode — International Business Machines Corporation, 2023, KR
- Low Resistance Composite Silicon-Based Electrode — International Business Machines Corporation, 2025, KR
- All-Solid-State Batteries, SSE Batteries, Lithium Metal Batteries with Boundary Layers — Celgard LLC, 2021, JP
- PET-Reinforced Dual-Crosslinked Poly(ionic liquid) Composite Solid Electrolyte — Peking University, 2025, CN
- Hollow Zirconium-Based Metal-Organic Framework Crosslinked Composite Solid Electrolyte — Southwest Jiaotong University, 2024, CN
- Plasma Technology to Polymerize PEO/Garnet-Type Solid Composite Electrolyte — Zhejiang University of Technology, 2026, CN
- Method for Detecting Electrolyte Dendrites in Solid-State Batteries — Beijing Institute of Technology, 2025, CN
- Fast-Charging Multi-Layer Composite Solid Electrolyte, Preparation Method and Application — Zhejiang University, 2025, CN
- Composite Solid Electrolyte Film with Ultra-High NASICON-Type Ceramic Content — Shanghai Jiao Tong University, 2024, CN
- Ionic Liquid-Based Quasi-Solid Electrolyte for Lithium Batteries — Beijing Institute of Technology, 2020, JP
- Quasi-Solid Alkali-Ion Battery Hyper-Crosslinked Polymer Electrolyte — Beijing Institute of Technology, 2025, CN
- Cationic Polymer Electrolyte and Its Preparation Method and Application — Anhui Huaqi Environmental Protection Technology, 2025, CN
- Poly(ionic liquid)/PVDF-HFP Solid Electrolyte with Microscopic Liquid Phase — Shaanxi University of Science and Technology, 2025, CN
- Solid Electrolyte Using Triazolium Ionic Liquid Monomer — Dankook University, 2025, KR
- Polymer Solid Electrolyte Laminate and Manufacturing Method — LG Energy Solution, 2026, JP
- Method for Producing Polymer Solid Electrolyte — LG Energy Solution, 2025, JP
- Electrolyte and All-Solid-State Battery Containing Same — LG Energy Solution, 2026, JP
- Composite Electrolyte Film, Preparation Method and Application in Solid-State Lithium Batteries — Harbin Institute of Technology, 2022, CN
- Composite Electrolyte Film, Preparation Method and Application in Solid-State Lithium Batteries — Harbin Institute of Technology, 2023, CN
- All-Solid-State Battery and Method for Manufacturing the Same — Honda Motor Company, 2025, JP
- Method for Manufacturing Positive Electrode and Solid Electrolyte Composite Structure for Battery — General Motors LLC, 2025, CN
- Elastomeric Electrolyte for High-Energy All-Solid-State Metal Batteries — Georgia Tech Research Corporation, 2024, CN
- Semi-Interpenetrating Polymer Network as Separator for Alkali Metal Batteries — Forschungszentrum Julich, 2022, CN
- International Energy Agency — Global EV Outlook and Solid-State Battery Technology Reports
- World Intellectual Property Organization (WIPO) — Patent Landscape Reports: Battery Technologies
- U.S. Department of Energy — Solid-State Battery Research Programs and Interface Engineering Priorities
All data and statistics on this page are sourced from the references above and from PatSnap's proprietary innovation intelligence platform. This landscape is derived from a limited set of patent and literature records retrieved across targeted searches. It represents a snapshot of innovation signals within this dataset only and should not be interpreted as a comprehensive view of the full industry.
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