Direct Air Capture Reimagined: The UIUC-Toyota Battery Patent
💡 University of Illinois (UIUC) and the Toyota Research Institute of North America have jointly filed two US patent applications - numbers 18/713,023 and 19/368,311 - for an electrochemical device that captures CO2 directly from atmospheric air using electricity and saltwater chemistry, with no heat required. The device works like a rechargeable battery: it swings the pH of a potassium-based solution to absorb ambient CO2, then reverses the process to release a concentrated stream ready for storage or reuse. Published July 12, 2026 in Environmental Science and Technology, the invention targets the "legacy" CO2 already diffused through the atmosphere at just 0.04% - the hardest problem in climate technology.
What the Patent Claims: A Battery That Breathes In CO2
Most carbon capture methods work with concentration. A coal plant's exhaust is 10-15% CO2, easy to scrub. Atmospheric air holds just 0.04%. Pulling carbon from that dilute mixture requires either enormous airflows or highly reactive chemistry. Today's commercial direct air capture (DAC) systems use potassium hydroxide (KOH) to react with atmospheric CO2, forming potassium carbonate. The problem: regenerating that KOH for reuse requires a kiln at roughly 900 degrees Celsius, consuming 2,000 to 3,000 kWh per tonne of CO2 captured.
Patent applications 18/713,023 and 19/368,311 describe a cell in which potassium-stabilized alpha-phase manganese dioxide (K-MnO2) electrodes intercalate and release protons - the same fundamental mechanism that makes a lithium-ion battery charge and discharge. When the cell runs in one direction, the electrolyte solution becomes more alkaline (higher pH), enabling it to absorb CO2 from the surrounding air. Reversed, the pH drops and the absorbed CO2 is released as a concentrated stream, ready for geological sequestration or industrial use.
The design is what researchers call a "cation-compensated" cell: protons move through the electrode material, while potassium cations move through the solution to maintain charge balance. The result is a thermodynamic cycle applied to dissolved inorganic carbon rather than temperature and pressure. That framing matters because it gives engineers a precise target: minimize entropy generation at each step, just as heat engine designers do. This is where the battery analogy is most exact. The step after closing the loop is improving it.
Why Direct Air Capture Is Both Essential and Stubbornly Expensive
Global CO2 emissions run around 37 billion tonnes per year. Even if humanity stopped all new emissions today, the roughly 1.5 trillion tonnes of CO2 accumulated in the atmosphere since industrialization would continue driving climate change for centuries. Direct air capture addresses that legacy problem - but at current prices of $400 to $1,000 or more per tonne, removing even one billion tonnes annually would cost $400 billion to a trillion dollars. That burden is unsustainable.
Progress is real but the gap remains vast. The US Department of Energy has committed $3.5 billion for large-scale DAC hubs. Occidental/Carbon Engineering's Stratos plant in Texas, designed for 500,000 tonnes per year, cost $1.3 billion to build. The global DAC market stood at roughly $147 million in 2025 and is projected to reach $17.6 billion by 2035, a 61% compound annual growth rate. Yet the gap between today's commercial reality and the DOE's $100-per-tonne target remains enormous. Energy is the dominant cost driver. If the heat-based regeneration step can be replaced by an electrical one, powered by cheap renewables, the entire cost curve shifts. Electrochemical approaches target 700 to 1,000 kWh per tonne - a substantial reduction from today's 2,000 to 3,000 kWh. But they require electrodes, electrolytes, and process chemistry that can survive tens of thousands of cycles at industrial scale. That is precisely the challenge the UIUC-Toyota invention aims to solve.
The Proton-Intercalation Trick: How the Device Actually Works
The core chemistry of the UIUC-Toyota device is the proton-intercalation cycle. Alpha-phase manganese dioxide has a tunnel structure that can accept and release protons without breaking apart - the same stable host-guest chemistry that makes MnO2 useful in ordinary alkaline batteries. By stabilizing this structure with potassium ions, the researchers created electrodes that can reliably swing the local pH of a saltwater electrolyte back and forth.
In the "capture" half-cycle, the electrode accepts protons from the electrolyte, making the solution more basic (high pH). At high pH, CO2 from ambient air dissolves readily into the solution, forming bicarbonate and carbonate ions. In the "release" half-cycle, the electrode returns its stored protons, acidifying the electrolyte and reversing the equilibrium - dissolved inorganic carbon converts back to CO2 gas, which can then be collected.
The current primary engineering challenge is inter-stream mixing: when the system switches between the two liquid streams during cycling, some mixing occurs, diluting the alkaline capture solution and contaminating the acidic release stream. The research team notes this is "one of the biggest issues we're dealing with now." Solving it would significantly improve both energy efficiency and throughput - and is a central focus of the ongoing patent-protected development work. The key insight is that treating this problem as a thermodynamic cycle opens the door to systematic optimization.
What This Depends On - and What It Could Unlock
The electrochemical DAC approach sits at the intersection of two major technology curves. First, the cost of solar and wind electricity, which has fallen roughly 90% since 2010 and keeps declining. An electrochemical process powered by cheap renewables improves its economics just by waiting: as solar costs fall, operating costs follow. Second, the maturity of battery electrode materials. MnO2 has been used in batteries for more than a century - its electrochemistry is well understood, its supply chain exists, and its degradation mechanisms are mapped. The UIUC-Toyota patent does not invent a new material: it repurposes one already at industrial scale.
If the invention scales, it could enable distributed direct air capture: modular units running on local renewable power, requiring no gas heating, deployable anywhere wind or solar is abundant. Unlike the enormous cooling-tower contactors at the Stratos plant, which require centralized infrastructure, an electrochemical DAC unit might eventually fit in a shipping container. That changes the geographic calculus of who can run DAC and where. The carbon that emerges could feed synthetic fuels, concrete curing, or geological storage - all markets that benefit from a purer, more concentrated CO2 stream, which the electrochemical approach naturally produces.
Toyota's Stake: Why the EV Giant Is Backing Carbon Capture
Toyota's involvement is not accidental. The Toyota Research Institute of North America (TRINA) has built a portfolio of battery-adjacent materials science research, and the UIUC collaboration sits naturally inside it. For Toyota - navigating a complex transition toward EVs while also investing in hydrogen fuel cells - carbon capture represents a strategic hedge: it can sell the technology, deploy it to offset residual emissions, or license it to governments and utilities.
Japan has committed to carbon neutrality by 2050. Joint ownership of patent 19/368,311 between UIUC and Toyota means any commercial deployment requires both parties' agreement - giving Toyota a direct seat at the table if this technology reaches commercial scale. Beyond strategy, there is simple chemistry: Toyota's decades of research on battery electrode materials, electrolytes, and cell degradation feed directly into the challenge of building an electrochemical DAC system that survives millions of cycles at industrial scale. The EV revolution is, inadvertently, funding the materials science infrastructure that could underpin electrochemical carbon capture. That is the systems connection this patent makes visible.
Who Else Is Racing Here - and What Makes This Approach Different
The electrochemical DAC field is active but still early. Zhejiang University holds US12383858B2 (granted August 2025), covering an energy-saving system that uses ion-selective membranes to separate carbonate from hydroxide - a different electrochemical path to the same destination. Carbon Engineering (now Occidental/1PointFive) holds US12611629B2 (granted April 2026), protecting a bipolar membrane electrodialysis (BPMED) process that electrochemically regenerates its KOH capture solution. Both are already granted; the UIUC-Toyota applications are still pending.
The UIUC-Toyota approach is distinct in using solid-electrode proton intercalation rather than membrane-based ion transport. That offers potential advantages in durability (no membrane fouling) and system simplicity, but raises its own challenges around electrode longevity. With 130 or more DAC facilities globally in various stages of development as of 2024 (IEA), and the field's publication rate accelerating sharply, the IP landscape is filling fast. The battle for cost-effective electrochemical DAC will be decided partly in the lab and partly in the patent office - which makes both places worth watching.
| Feature | Details |
|---|---|
| Patent Applications | US 18/713,023 (UIUC); US 19/368,311 (UIUC + Toyota) |
| Title | Method and system for electrochemical-based carbon capture and sequestration/valorization |
| Assignees | University of Illinois; Toyota Research Institute of North America |
| Inventors | Kyle Smith, Paul Rozzi, JeongA Lee (UIUC); Chip Roberts, Tim Arthur (Toyota RINA) |
| Filed | 2024 (USPTO, USA) |
| Journal Publication | Environmental Science and Technology (ACS), July 12, 2026 |
| Jurisdiction | USA (USPTO) |
| Core Claim | Proton-intercalation electrochemical CO2 capture using K-stabilized MnO2 electrodes |
So What Does It Mean for Us?
The UIUC-Toyota patent applications mark a genuine advance in the architecture of direct air capture - not merely an incremental improvement of the existing KOH-calcination route. If the electrode durability and inter-stream mixing challenges are solved at scale, this approach could reduce DAC's energy intensity significantly and allow direct coupling with variable renewable energy sources - a meaningful step toward bringing costs within reach of the DOE's $100-per-tonne target.
What it does not yet promise is commercial deployment at the gigatonne scale the climate needs. The road from a laboratory cell to a 500,000-tonne-per-year facility is measured in decades and billions of dollars. But patent filings 18/713,023 and 19/368,311 suggest Toyota - one of the world's most disciplined large-scale manufacturers - sees enough promise to protect its stake in the outcome. When a company like Toyota backs a fundamental process patent in carbon capture, it signals the field is moving from academic curiosity toward an industrially credible alternative. That is, cautiously, a meaningful signal for the whole clean energy landscape.
FAQ
What are patent applications 18/713,023 and 19/368,311?
These are US patent applications filed by the University of Illinois (18/713,023) and jointly by UIUC and Toyota (19/368,311) for an electrochemical device that captures CO2 from ambient air. They were described in a paper published July 12, 2026 in Environmental Science and Technology. The applications are pending - not yet granted as issued patents.
How is this different from existing direct air capture technology?
Most commercial DAC systems use potassium hydroxide to absorb CO2, then regenerate it in kilns at around 900 degrees Celsius - a very energy-intensive step. The UIUC-Toyota approach replaces that heat with electrochemistry: proton intercalation in manganese dioxide electrodes swings the pH of a liquid electrolyte to absorb and release CO2, potentially consuming far less energy - targeting 700 to 1,000 kWh per tonne versus today's 2,000 to 3,000 kWh.
Why is Toyota involved in carbon capture research?
Toyota Research Institute of North America has a materials science team working on battery electrode chemistry - directly applicable to this device's MnO2 electrodes. Strategically, holding IP in carbon removal technologies gives Toyota flexibility as Japan's 2050 carbon neutrality commitment approaches and as the automotive sector faces growing pressure to offset residual emissions.
What does patent translation have to do with direct air capture patents?
When a US patent application like 19/368,311 is also filed internationally through the PCT route, targeting Japan, Europe, or China, it must be translated into the local language for examination. Patent translation for technical IP in chemistry or materials science requires specialists who understand both the science and the legal precision of patent claims - where a single mistranslated term can invalidate a claim.
When might electrochemical DAC reach commercial scale?
The UIUC-Toyota device remains at laboratory scale. Commercialization requires solving inter-stream mixing losses, demonstrating electrode longevity over millions of cycles, and proving the economics at pilot scale. Industry observers typically estimate 8 to 15 years from lab to industrial deployment for electrochemical climate technologies - making mid-2030s commercialization the optimistic scenario.
Sources
University of Illinois News Bureau - New Electrochemical Device (July 2026)
Scientific Frontline - Electrochemical Direct Air Capture of CO2 (July 2026)
Green Fuel Journal - Direct Air Capture Market Scaling 2026
Direct Air Capture in 2026 (unteachablecourses.com)
Google Patents - Carbon Engineering US12611629B2 (granted April 2026)
Google Patents - Zhejiang University US12383858B2 (granted August 2025)
About the author
Dao Huy (Lucas) is a professional translator with over seven years of experience working across English, Chinese, and French into Vietnamese. His core specialization covers technical translation, patent translation, and IP translation - including materials science, chemistry, and energy-sector patent applications like the ones discussed above. When a patent application filed in the United States needs to be pursued in Japan, Vietnam, or before the EPO, every claim, specification, and abstract must be translated with both scientific and legal precision. A mistranslated claim is a lost claim.
If you need patent translation, technical document translation, or software and technology localization into Vietnamese, Dao Huy is available for a quote at daohuy.com.
Written by Dao Huy (Lucas), Vietnamese translator & localization specialist (EN · ZH · FR → Vietnamese). See translation services →