Vanadium Electrolyte Thermal Stability Patents 2026
Vanadium Electrolyte Thermal Stability Patents
V(V) precipitation above 40°C remains the central barrier to wide-temperature VRFB deployment. This dataset spans phosphate additives, mixed chloride electrolytes, and capacity recovery approaches across 13 assignees and 7 jurisdictions.
Why Vanadium Electrolyte Thermal Stability Matters
Standard VRFB systems are constrained to a 10–40°C operational window because V(V) ions precipitate as V₂O₅ above approximately 40°C and V(II)/V(III) species crystallize below roughly 10°C in sulfuric acid electrolytes. This dual precipitation problem forces expensive active thermal management hardware into balance-of-plant designs.
Within this dataset, four primary technology sub-domains address the problem: phosphate and polyphosphate additive stabilization of V(V), mixed sulfate-chloride supporting electrolytes forming thermally stable neutral vanadium species, ancillary Ce³⁺/Ce⁴⁺ redox couple augmentation, and system-level electrolyte management strategies including precipitate dissolution and capacity recovery.
Quantitative gains are substantial. In a 3 mol/L V(V) system at 30°C, 1 wt% H₃PO₄ extended precipitation induction time from 3 days to over 47 days. The HEDP organophosphonate at 0.5 wt% extended V(V) stability at 50°C from 5 days to 30 days. The Battelle chloride approach explicitly claims operation from −35°C to 60°C without active thermal management devices.
In this dataset, 13 distinct assignees are identifiable across approximately 7 jurisdictions. Battelle Memorial Institute holds the largest single-assignee cluster in retrieved records with approximately 10 patent records, followed by JD Holding Inc. with approximately 8 records and Hydraredox Technologies Holdings Ltd. with 6 records.
Filing Activity and Technology Cluster Distribution
The dataset reveals a clear three-phase innovation arc from foundational HED electrolyte IP (1996–1999) through mid-stage additive and mixed-acid development (2001–2015) to precisely specified formulations and lifecycle management approaches (2019–2026).
Patent Records by Technology Cluster (Dataset Snapshot)
In this dataset, the mixed sulfate-chloride cluster (Battelle family, ~10 records) and phosphate additive cluster together account for the largest share of retrieved records, with capacity recovery and ancillary couple approaches representing smaller but growing portions.
↗ Click bars to exploreFiling Activity by Innovation Phase (Dataset Snapshot)
In this dataset, the 1996–1999 foundational phase contributed approximately 6 records, the 2001–2015 mid-stage phase contributed the largest share (~22 records), and the 2019–2026 recent phase shows accelerating activity with approximately 12 records focused on precise formulation specifications and lifecycle management.
↗ Click bars to exploreKey Application Domains for VRFB Electrolyte Thermal Stability Technology
Retrieved records address three distinct application contexts: large-scale grid-connected stationary storage, industrial electrolyte manufacturing, and in-service electrolyte lifecycle management and capacity recovery.
Grid-Scale Stationary Energy Storage
The dominant application across all retrieved records is grid-connected stationary storage for renewable integration, peak shaving, frequency regulation, and load leveling across 4–24 hour durations. The Battelle chloride electrolyte family explicitly claims elimination of active thermal management hardware, targeting outdoor deployment across wide ambient temperature ranges. The 2023 academic overview study frames design optimization explicitly for utility-scale 4–24 hour storage durations.
Stationary StorageIndustrial Electrolyte Manufacturing
Lotte Chemical Corporation (Korea) and the Institute of Process Engineering (Chinese Academy of Sciences) represent a distinct sub-domain covering industrial manufacture of electrolyte as a commodity product, embedding thermal stability controls in the preparation process. Methods include catalytic reduction, fluidized-bed reduction, and UV activation for producing stable V³⁺ to V⁴⁺ electrolyte at scale, with records spanning US, AU, CA, NZ, and EP jurisdictions from 2017–2024. VRB Energy Inc.’s 2023 paste electrolyte patent targets reduced transport cost and corrosion risk.
Electrolyte ManufacturingElectrolyte Lifecycle Management
VRB Energy Inc.’s 2024–2026 pending US and EP patents address in-service electrolyte degradation, including capacity fading from thermal precipitation events, remediated through chemical reduction rather than full electrolyte replacement. This shifts the thermal stability problem from a design constraint to a maintenance parameter, targeting reduced total cost of ownership for deployed VRFB assets. The 2026 EP application represents the most recent filing in this dataset.
Lifecycle ManagementHigh-Concentration Precipitate Control
Showa Denko K.K. (now Resonac Holdings) patented a system-level approach that builds particle size adjustment means into the electrolyte circulation loop to enable stable operation at vanadium concentrations of ≥1.7 mol/L by mechanically preventing precipitate accumulation. Suzhou Rongke Power Co., Ltd. developed a mixed chloride-sulfate formulation constraining the [c(Cl⁻) + c(SO₄²⁻)]/c(Vⁿ⁺) ratio to 2.9–3.6, simultaneously suppressing Cl₂ evolution and maintaining thermal stability for commercial deployment safety.
System-Level StabilizationLeading Patent Assignees in Vanadium Electrolyte Thermal Stability — Dataset Snapshot
In this dataset, Battelle Memorial Institute holds the largest single-assignee cluster with approximately 10 retrieved records spanning 2012–2024, followed by JD Holding Inc. with approximately 8 records (1996–2008) in retrieved records. Chinese assignees collectively account for approximately one-third of retrieved records.
Top Assignees by Filing Count in Retrieved Records (Dataset Snapshot)
↗ Click bars to exploreBattelle Memorial Institute
Battelle Memorial Institute (Pacific Northwest National Laboratory, US Department of Energy) holds the largest single-assignee cluster in this dataset with approximately 10 retrieved patent records spanning 2012–2024 across US, WO, EP, CA, and IN jurisdictions. All records relate to chloride-supported electrolyte systems that form the neutral VO₂Cl(H₂O)₂ species, explicitly claiming operation from −35°C to 60°C without active thermal management devices. Multiple records are continuations of a 2010 priority application; the family includes active US grants and a 2024 EP record.
United StatesHydraredox Technologies Holdings Ltd.
Hydraredox Technologies Holdings Ltd. (Australia) holds 6 retrieved records across AU, EP, US, IN, and WO jurisdictions spanning 2014–2020, all representing the Ce³⁺/Ce⁴⁺ ancillary redox couple approach at 100–500 mmol/L in the positive electrolyte. A 2020 EP filing extended the portfolio to methane-sulfonic acid variants. The portfolio is reported as active in EP and US as of the dataset, targeting electrochemical rather than chemical stabilization of the positive half-cell.
AustraliaFour Emerging Directions in VRFB Electrolyte Thermal Stability (2022–2026)
Based on filings from 2022–2026 in this dataset, the field is transitioning from exploratory additive screening toward precisely engineered electrolyte compositions with defined conductivity, concentration ratio, and temperature performance specifications, alongside new operational recovery approaches.
Precisely Specified Chloride-Free High-Temperature Formulations
Fraunhofer Society’s 2024 DE and US patents define conductivity of 280–420 mS·cm⁻¹ as a performance-linked parameter for operation above 40°C without chloride. This shift from qualitative additive descriptions to quantitatively bounded specifications signals movement toward standardized, certifiable electrolyte compositions for industrial procurement — a prerequisite for commodity electrolyte markets. Both filings carry active or pending status as of this dataset.
Mixed Anion Electrolytes with Chlorine Evolution Management
Suzhou Rongke Power Co., Ltd.’s 2022–2025 AU and CA filings address a practical commercialization barrier for mixed sulfate-chloride electrolytes: Cl₂ gas evolution causing material corrosion. Constraining the [c(Cl⁻) + c(SO₄²⁻)]/c(Vⁿ⁺) ratio to 2.9–3.6 simultaneously suppresses Cl₂ evolution and maintains thermal stability. This engineering refinement signals the chloride-based approach is transitioning from laboratory concept to industrial deployment.
Phosphate Additive vs. Mixed Sulfate-Chloride Electrolyte Approaches
Click any row to explore further.
| Dimension | Phosphate Additive (H₃PO₄ / HEDP) | Mixed Sulfate-Chloride (Battelle) |
|---|---|---|
| Phosphate coordinates with VO₂⁺ ions, disrupting V₂O₅ lattice nucleation | Cl⁻ ions form neutral VO₂Cl(H₂O)₂ species instead of ionic [VO₂(H₂O)₃]⁺ | N/A — see Entity A and B |
| Extends stability at 50°C; HEDP 0.5 wt% extends V(V) stability from 5 to 30 days at 50°C | Explicitly claims −35°C to 60°C without active thermal management devices | N/A — see Entity A and B |
| Demonstrated in 3 mol/L V(V) systems; 1 wt% H₃PO₄ extends induction time to over 47 days at 30°C | Not specified in terms of concentration limits in retrieved records | N/A — see Entity A and B |
| Fraunhofer Society (2024), Dalian Rongke Power (2016), The Kansai Electric Power Co. (2002–2011) | Battelle Memorial Institute (2010–2024), Wattjoule Corporation (2018), Suzhou Rongke Power (2022–2025) | N/A — see Entity A and B |
| Fraunhofer DE active, US pending (2024); older Kansai/Rongke phosphate patents partially expired | Battelle family: multiple active US, CA, EP, IN grants through at least 2022; 2024 EP record active | N/A — see Entity A and B |
| Additive concentration optimization; conductivity window must be maintained (280–420 mS·cm⁻¹ per Fraunhofer) | Cl₂ gas evolution causing material corrosion; Suzhou Rongke addresses via anion ratio constraint of 2.9–3.6 | N/A — see Entity A and B |
| Chloride-free; Fraunhofer 2024 explicitly targets chloride-free formulation | Requires HCl co-supporting electrolyte; Cl⁻ ion is fundamental to mechanism | N/A — see Entity A and B |
| Grid-scale storage, high-temperature VRFB operation, standardized electrolyte commodity market | Grid-scale storage with passive thermal management; eliminates active cooling balance-of-plant cost | N/A — see Entity A and B |
Frequently Asked Questions: Vanadium Electrolyte Thermal Stability Patents
V(V) ions (VO₂⁺) in the positive electrolyte are prone to precipitation as V₂O₅ at temperatures above approximately 40°C under conventional sulfuric acid formulations. At low temperatures (below ~10°C), V(II) and V(III) species in the negative electrolyte are susceptible to crystallization. This dual precipitation problem restricts standard VRFB systems to an operational window of approximately 10–40°C.
In a 3 mol/L V(V) system at 30°C, an untreated solution precipitated within 3 days, while 1 wt% H₃PO₄ extended the induction time to over 47 days. Among organic phosphonates, HEDP (1-hydroxyethylidene-1,1-diphosphonic acid) at 0.5 wt% extended V(V) stability at 50°C from 5 days to 30 days.
The Battelle Memorial Institute (Pacific Northwest National Laboratory) chloride-supported electrolyte filings explicitly claim operation between −35°C and 60°C without active thermal management devices. The mechanism involves Cl⁻ ions causing V(V) to form the neutral species VO₂Cl(H₂O)₂ rather than the ionic [VO₂(H₂O)₃]⁺ found in pure sulfate systems.
The foundational HED electrolyte IP from JD Holding Inc., Pinnacle VRB, and Unisearch Limited, dating to 1996–2003, is substantially expired or inactive in this dataset, meaning the core concept of supersaturated vanadium electrolyte with phosphate stabilization is now in the public domain. R&D teams can build on these foundations without licensing concern, but must navigate the active Battelle chloride patent family if pursuing mixed-acid approaches.
Fraunhofer Society’s 2024 DE and US patents define a chloride-free phosphoric acid formulation with a conductivity window of 280–420 mS·cm⁻¹ as a performance-linked parameter for operation above 40°C. Both filings carry active or pending status as of this dataset and represent a shift toward quantitatively bounded electrolyte specifications suitable for industrial procurement.
VRB Energy Inc.’s 2024–2026 pending US and EP patents address the problem that capacity fading in deployed systems — including from thermal events causing partial precipitation — can be remediated through chemical reduction rather than full electrolyte replacement. This shifts the thermal stability problem from a design constraint to a maintenance parameter, potentially reducing total cost of ownership for deployed VRFB assets.
Data and insights on this page are based on a limited patent and literature dataset and are for reference only. Figures may not represent the complete technology landscape.