Solid-State Battery Electrolytes & Interface Engineering — Patent & Technology Landscape 2020–2026 | PatSnap
Solid-State Battery Electrolytes & Interface Engineering: A Global Patent & Technology Landscape
The solid-state battery electrolyte and interface space has become one of the most contested patent battlegrounds in energy storage. This landscape maps 32,786 patent families across four electrolyte families — sulfide, oxide, polymer and halide — and the cross-cutting interface engineering that unifies them.
A 32,786-patent battleground at the electrolyte–interface intersection
Across 2020–2026 the global corpus reaches 32,786 patent families at the intersection of electrolyte chemistry and interface engineering, with annual filings climbing from ~3,936 in 2020 to a peak near 6,840 in 2024 — a 74% rise in five years. Japan and South Korea dominate the rankings, but China-origin filings have surged since 2022.
The four electrolyte families each occupy distinct trajectories. Sulfide remains the largest single cluster at 8,676 patents, while electrode–electrolyte interface engineering has emerged as the unifying challenge across all chemistries with 6,448 patents of its own.
Counts are drawn from structured retrieval across title, abstract and claims (TACD). The 2025–2026 totals are materially understated due to the ~18-month publication lag — the 2026 figure of 285 reflects only mid-year publications.
Patent count by electrolyte cluster (2020–2026)
↗ Hover bars for valuesPatent corpus by cluster
| Cluster | Patents (2020–26) | CAGR (approx.) | Dominant assignee region |
|---|---|---|---|
| Overall SSB electrolyte corpus | 32,786 | ~11% | Japan / South Korea |
| Sulfide electrolyte | 8,676 | ~14% | Japan (Toyota, Panasonic) |
| Electrode–electrolyte interface | 6,448 | ~10% | South Korea (LG, Samsung) |
| Halide electrolyte | 2,289 | ~32% | Japan (Panasonic, Toyota) |
| Oxide electrolyte | 2,764 | ~8% | Japan / China |
| Polymer electrolyte | 2,287 | ~7% | South Korea / China |
Filings accelerated 74% to a 2024 peak
The 2022–2024 window was the most productive phase of patent output in the field, with halide electrolytes expanding nearly four-fold over the same period.
Overall corpus filings by year
Patent families filed per year, 2020–2024.
↗ Hover barsFilings by cluster, 2020–2024
Sulfide, interface and halide trajectories.
↗ Hover pointsFilings by year and cluster
| Year | Overall | Sulfide | Interface | Halide |
|---|---|---|---|---|
| 2020 | 3,936 | 840 | 778 | 121 |
| 2021 | 4,377 | 1,062 | 930 | 194 |
| 2022 | 5,475 | 1,402 | 1,144 | 304 |
| 2023 | 5,981 | 1,534 | 1,238 | 412 |
| 2024 | 6,840 | 1,938 | 1,334 | 600 |
| 2025* | 5,892 | 1,827 | 978 | 631 |
| 2026* | 285 | 73 | 46 | 27 |
*2025–2026 figures are significantly understated due to the ~18-month publication lag. Halide grew 396% from 2020 to 2024 (121 → 600), the fastest-emerging sub-field; sulfide remains the largest single cluster.
Japan and Korea anchor the IP; China surges since 2022
Based on applicant headquarters and filing patterns across the corpus.
Filing share by region
| Region | Share | Key filers |
|---|---|---|
| Japan | 35–38% | Toyota, Panasonic, Honda, Nissan, Murata |
| South Korea | 22–25% | LG Energy Solution, Samsung SDI, Hyundai/Kia |
| China | 18–22% | CATL, BYD, Geely, WeLion, Ganfeng, SVOLT |
| United States | 10–12% | GM, QuantumScape, Solid Power, Apple, universities |
| Europe | 4–6% | BMW, Bosch, BASF, Fraunhofer institutes |
| Others | 3–5% | Canada, Australia, Israel (StoreDot) |
Four electrolyte families, four trajectories
Each family clusters around its own chemistry, technical approaches and leading assignees — sulfide on conductivity, oxide on stability, polymer on processability, halide on high-voltage compatibility.
Sulfide electrolytes
8,676 patentsCore chemistry: Li6PS5Cl (argyrodite), Li10GeP2S12 (LGPS), β-Li3PS4, Li2S–P2S5 glass-ceramics, thio-LISICON
Top assignees — sulfide cluster
↗ Hover barsOxide electrolytes
2,764 patentsCore chemistry: LLZO (Li7La3Zr2O12) garnet, NASICON-type (LATP, LAGP), LIPON thin film, perovskite (LLTO)
Top assignees — oxide cluster
↗ Hover barsPolymer electrolytes
2,287 patentsCore chemistry: PEO-based SPE, PVDF/PVDF-HFP gel polymer, polycarbonate, nitrile polymers, composite polymer electrolytes (CPE)
Top assignees — polymer cluster
↗ Hover barsHalide electrolytes
2,289 patents Fastest-growing · +396%Core chemistry: Li3InCl6, Li3YCl6, Li3ErCl6, Li3HoCl6, oxyhalide variants, fluoride-substituted halides
Top assignees — halide cluster
↗ Hover barsInterface engineering — the cross-cutting challenge
The electrode–electrolyte interface cluster holds 6,448 patents and tracks the overall corpus, confirming it as a pervasive challenge across every chemistry. Korean majors lead manufacturing-ready solutions.
Top assignees — interface cluster
↗ Hover bars① Cathode-side coatings
Thin oxide/halide coatings (LiNbO3, Li2ZrO3, Al2O3, Li3PO4, LiF) on NMC/NCA/LCO particles via ALD or wet-chemistry to suppress cathode–sulfide reaction. Samsung SDI and Toyota lead.
② Li-metal anode interface
Artificial SEI (Li3N, LiF, Li2O, LIPON) and ionic-liquid interlayers to block dendrites and cut impedance, especially anode-free Cu configurations. LG leads.
③ Alloy anode interfaces
Li-In, Li-Al, Li-Si, Li-Sn alloys in sulfide cells to avoid direct Li-metal/SE contact. Toyota’s sulfide cells predominantly use Li-In.
④ Buffer / interlayer insertion
Thin Li3PO4, LIPON, polymer or ionic-liquid layers between SE and electrode to absorb volume change and improve wettability. Active for LLZO + Li-metal.
⑤ In-situ interface formation
Controlled reaction forming a stable, ionically conducting interphase during initial cycling. Strong growth 2023–2025.
⑥ 3D structured interfaces
Patterned/porous SE surfaces and 3D Li-metal anodes to raise contact area and lower current density. University-originated, startup-commercialized.
⑦ Mechanical pressure engineering
Stack-pressure optimization and elastic interlayers to keep intimate contact during cycling — critical for sulfide cells with volume change.
The seven IP power players
Japan holds the deepest sulfide moat; Korea dominates manufacturing-ready interface engineering; China has become a top-tier filing group since 2022.
Toyota Motor Corp.
Sulfide-based all-solid-state EV cells built on argyrodite and LGPS SEs, with Li-In alloy anodes, wet-process SE sheet fabrication, bipolar stacking, and LiNbO3 cathode buffers. Public production target: 2027–2028.
LG Energy Solution
Weighted toward interface engineering and anode-free architectures: in-situ polymerization, artificial SEI on Cu foil, PVDF composite–sulfide hybrids, and cathode surface coatings.
Panasonic IP Mgmt.
Largest halide portfolio globally — Li3InCl6/Li3YCl6 synthesis, halide–oxide composites, NMC integration in bipolar cells. Also strong in sulfide (459) with wet-chemistry and cold-press fabrication.
Samsung SDI
Spans sulfide chemistry (LGPS Ge-free, argyrodite) and interface engineering (NMC buffer layers, Li-metal pre-lithiation, space-charge suppression). Targeting pouch-cell SSBs, ~2027.
CATL
Condensed-battery strategy using semi/quasi-solid electrolytes as a step toward full SSB: LLZO garnet cells, in-situ polymerization, polymer–ceramic composites. Full SSB targeted 2027–2030.
QuantumScape
LLZO-based ceramic separator for anode-free Li-metal cells: thin (<50 µm) dense LLZO, in-situ Li plating on Cu, proprietary densification, LLZO–Li interface management. Limited production with Volkswagen.
GM Global Tech.
With SES AI and Solid Power: sulfide SE slurry-coated electrodes, roll-to-roll processing, artificial SEI for Li-metal, and Si-dominant anode–sulfide interfaces.
Eight directions defining the next filing wave
The 2024–2026 cohort reveals where the field is heading.
Oxyhalide & mixed-anion electrolytes
Combining oxide and halide anions (Li2ZrCl6, oxyhalide perovskites) to pair halide oxidative stability with better reductive stability and moisture resistance. Panasonic, Toyota and Chinese universities lead.
Anode-free architectures
Li plates in situ on engineered Cu/carbon current collectors, cutting cell weight and cost 20–30%. Focus on 3D collectors and LiF/Li3N artificial SEI bilayers. LG and QuantumScape lead.
In-situ polymerization & reactive filling
Injecting liquid monomers (1,3-dioxolane, fluorinated acrylates) and polymerizing in-cell — now a major industrial area. CATL, LG and Samsung filed extensively 2023–2025.
Bipolar stacking with thin-sheet SE
Ultra-thin, pinhole-free SE sheets (<50 µm) for high-voltage modules without external wiring: sulfide wet-cast (Toyota, Nissan), halide tape-cast (Panasonic, FUJIFILM).
AI/ML-guided composition discovery
Computational screening of SE compositions with ML, high-throughput synthesis robots and automated testing. IBM, MIT-licensed startups and Chinese labs (DICP, SICCAS) are early filers.
Halide moisture-stability engineering
Fluoride partial substitution (Li3InCl6-xFx), surface passivation and dry-room-compatible synthesis to overcome halides’ primary commercialization barrier. FUJIFILM, Panasonic, Geely.
Pressure-less / low-pressure cells
Elastic interlayers, SE plasticity enhancement and housing designs to escape the 5–50 MPa stack pressure sulfide cells need — critical for automotive packaging. Toyota, Honda, GM.
Silicon-composite anodes with SSE
Moving beyond Li-metal to Si-dominant anodes (300–1,000 mAh/g) with solid electrolytes; interface patents for volume-expansion management grew sharply. Enevate and GM lead.
Electrolyte types compared
Indicative technology-readiness, advantages, challenges, leaders and commercial timelines by electrolyte type.
| Type | TRL (2026) | Key advantages | Key challenges | Leading players | Timeline |
|---|---|---|---|---|---|
| Sulfide | 6–7 | Highest conductivity (≤25 mS/cm); soft, RT-processable | Air/moisture sensitivity; narrow window | Toyota, Panasonic, Samsung SDI | EV: 2027–2030 |
| Oxide (LLZO) | 5–6 | Wide window; Li-metal compatible; thermally stable | Brittle; high sintering temp; GB resistance | QuantumScape, Murata, CATL, Toyota | Premium EV: 2028–2032 |
| Oxide (NASICON) | 5–6 | Good conductivity; LATP commercially available | Ti4+ reduction by Li-metal; needs buffer | Murata, TDK, academic | Aqueous/hybrid: 2025–2027 |
| Halide | 4–5 | Oxidative stability >4.5 V; no buffer needed | Moisture sensitivity; reductive instability; cost | Panasonic, Toyota, CATL | EV/consumer: 2028–2032 |
| Polymer (SPE) | 6–7 | Flexible; scalable; low cost | Low RT conductivity; narrow window | LG, BYD, Solid Power | Wearable: 2025–27; EV: 2028+ |
| Polymer (in-situ) | 4–5 | Intimate contact; scalable injection | Long-term stability; gas evolution | CATL, LG, Samsung | EV: 2028–2030 |
Ten representative patents
Illustrative of the major technical approaches; legal status as of mid-2026. Core invention points are from title/abstract-level evidence — full claim analysis requires reading the complete claims.
| Patent | Assignee | Filing | Status | Type | Core invention |
|---|---|---|---|---|---|
| US10826126B2 | Toyota | 2018 (gr. 2020) | Granted | Sulfide (argyrodite) | Li6PS5Cl SE with controlled Cl/Br ratio; >10 mS/cm; wet-process SE sheet |
| US11251461B2 | QuantumScape | 2020 | Granted | Oxide (LLZO) | Thin-film LLZO separator (<50 µm) for anode-free Li-metal; Cu collector interface |
| CN113097560A | CATL | 2021 | Active | Polymer composite | In-situ polymerization; monomer injected and polymerized in-cell; no external pressure |
| US20230006234A1 | Samsung SDI | 2022 | Active | Sulfide (LGPS) | Ge-free Li10SiP2S12; improved air stability; Li3PO4 buffer on NMC811 |
| US20230006249A1 | LG Energy Sol. | 2022 | Active | Interface | Anode-free with LiF-rich artificial SEI on Cu; >80% retention at 500 cycles |
| EP3937294A1 | Panasonic | 2020 | Active (EP) | Halide (Li3InCl6) | Mechanochemical Li3InCl6; 1.5 mS/cm; stable to 4.8 V; direct NMC contact |
| US20220344695A1 | Toyota | 2022 | Active | Sulfide + interface | Li-In alloy anode; pre-lithiation of In foil; stack-pressure optimization |
| CN115172862A | WeLion | 2022 | Active | Oxide (LLZO) | Ta/Al co-doped LLZO; 1.2 mS/cm; polymer interlayer; semi-solid hybrid |
| US20240014430A1 | GM | 2023 | Active | Sulfide + interface | Roll-to-roll sulfide sheet; Li3N/LiF bilayer SEI; Si-dominant anode |
| US20240154163A1 | Panasonic | 2023 | Active | Halide composite | Li3YCl6–LLZO composite; bipolar architecture; 2.1 mS/cm |
Value chain & ecosystem
Key materials, players and bottlenecks across the solid-state battery supply chain.
| Segment | Key materials / tech | Key players | Region | TRL/MRL | Bottlenecks |
|---|---|---|---|---|---|
| Raw materials | Li2S, P2S5, LiCl, InCl3, YCl3, La2O3, ZrO2, LiOH | Albemarle, SQM, Ganfeng, Idemitsu, Solvay | Global | MRL 7–9 | Li2S purity; rare-earth halide cost; P2S5 handling |
| SE synthesis | Argyrodite, LGPS, LLZO, Li3InCl6 | Idemitsu, Mitsui, Panasonic, NEI, Ampcera | JP/US/CN | MRL 5–7 | Scale-up yield; moisture control; batch consistency |
| SE sheet fabrication | Wet-cast, tape-cast, cold-press, SPS | Toyota, Panasonic, Murata, FUJIFILM | Japan | MRL 4–6 | Pinhole-free thin sheets; roll-to-roll yield |
| Electrode–SE integration | Cathode coating, composite electrode | Samsung SDI, LG, CATL, GM | KR/CN/US | MRL 4–6 | Uniform coating; ionic contact; co-sintering |
| Cell assembly | Stacking, pressure mgmt, packaging | Toyota, Samsung SDI, QuantumScape, Solid Power | JP/KR/US | MRL 3–5 | Dry-room needs; stack pressure; yield |
| Module / pack | Bipolar stacking, thermal mgmt | Toyota, CATL, BMW, VW (QuantumScape) | JP/CN/EU | MRL 2–4 | Pack-level pressure; thermal runaway |
Five strategic takeaways
Japan holds the deepest sulfide IP moat
Toyota’s 745 sulfide patents and Panasonic’s 459 form a formidable barrier in argyrodite and LGPS chemistry — new entrants must design around or license.
Halide is the most strategically open sub-field
Despite 396% growth, the halide cluster is young and many compositions remain unpatented. Chinese filers (CATL, Geely, Suzhou Qingtao) are staking positions alongside Panasonic and Toyota.
Interface engineering is the decisive differentiator
With 6,448 patents and LG/Samsung dominating, solving cathode-coating uniformity, Li-metal SEI stability and contact-loss will determine which chemistry reaches mass production first.
China’s filing surge signals a structural shift
CATL, BYD, Geely, WeLion and university spinouts collectively became a top-3 national filer group by 2024, concentrated in polymer composites, NASICON oxides and halides.
Anode-free + halide/oxide SE is the high-value convergence
Combining anode-free energy density with halide/oxide oxidative stability addresses the two biggest SSB challenges at once; activity here grew ~45% from 2023 to 2024 — the most contested white space for 2025–2027.
Solid-state battery electrolytes — FAQ
Across 2020–2026 the corpus reaches 32,786 patent families, with annual filings growing ~74% from ~3,936 (2020) to a ~6,840 peak (2024). 2025–2026 are understated by a ~18-month publication lag.
Halide electrolytes — filings rose 396% from 2020 to 2024 (121 → 600) as Li3InCl6/Li3YCl6 moved toward industrial use, helped by oxidative stability above 4.5 V.
Japan (Toyota 745 sulfide; Panasonic 360 halide) leads chemistry; Korea (LG 547, Samsung SDI 432 interface) leads interface engineering; China (CATL, BYD, Geely, WeLion) surged since 2022.
Its 6,448-patent cluster tracks the overall corpus. Strategies span cathode coatings, artificial SEI, alloy anodes, buffer interlayers, in-situ interphase, 3D interfaces and stack-pressure engineering.
Oxyhalide/mixed-anion electrolytes, anode-free architectures, in-situ polymerization, bipolar thin-sheet SE, AI/ML composition discovery, halide moisture engineering, low-pressure cells and Si-composite anodes.
Sulfide EV cells target 2027–2030; oxide/LLZO premium EV 2028–2032; halide 2028–2032; polymer already entering wearables, EV from 2028.
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