Updated · July 2026
How close are we to electrochemical ammonia?Can we make fertilizer directly with electricity?
Can we make fertilizer directly with electricity?How close are we to electrochemical ammonia?
Verified lithium-mediated cells now combine high selectivity with continuous operation, but no system has simultaneously demonstrated industrial current density, energy efficiency, scale and lifetime.Small cells can now make ammonia from nitrogen reliably for days, but they are still far too slow and energy-hungry to replace an ammonia plant.
Recorded milestones
Lithium-mediated fixation reported
Whole-cell energy gap measured
Open tests · conceptual branches
- OPEN TEST04 ↗Make ammonia about ten times fasterReach 400 mA/cm² ammonia partial currentThe strongest comparable 2024 result was 38.4 mA/cm² of ammonia-producing current; the 400 line is modeled, not achieved.Demonstrate at least 400 mA/cm² NH3 partial current, the rate used by a 2022 economic model for sub-$1/kg ammonia, without sacrificing efficiency or life.
The path shows Whole-cell energy gap measured. Open thresholds are separate tests in a conceptual map, not a forecast. No single percentage represents progress.
Where we standWhere we stand
The current stage, the evidence recorded, and the single threshold that gates the next stage.The stage reached, the evidence recorded, and the one test still blocking the next step.
What the evidence has shownWhat the evidence has shown
Small cells can now make ammonia from nitrogen reliably for days, but they are still far too slow and energy-hungry to replace an ammonia plant.Verified lithium-mediated cells now combine high selectivity with continuous operation, but no system has simultaneously demonstrated industrial current density, energy efficiency, scale and lifetime.
The next testBlocking threshold
Make ammonia about ten times fasterReach 400 mA/cm² ammonia partial currentAn independently measured integrated stack must pair industrial rate with high energy efficiency, selectivity and long life.An independently measured integrated stack must pair industrial rate with high energy efficiency, selectivity and long life.
What would count as proof?What would count as proof?
A clear test, the evidence behind it, and the limits of the claim.A clear test, the evidence behind it, and what it still leaves open.
Prove the ammonia came from nitrogen gasVerify nitrogen provenance
Trace ammonia is common in laboratories, so isotope controls must rule out false positives.Use quantitative 15N2 controls and blanks to prove that measured ammonia came from supplied dinitrogen rather than contamination.
Recorded result A rigorous Nature protocol quantified contamination and confirmed lithium-mediated nitrogen reduction.
Next test Apply quantitative isotope balance and blank controls to every claimed scale, rate or efficiency record.
SOURCE RECORD
Nature (2019) - rigorous isotope protocol ↗Still to demonstrateWhat this does not establishA separate system can still have different conditions and results.The named measurement has no wider implication until the supporting system test is also shown.
View every evidence record
Achieved
Prove the ammonia came from nitrogen gasVerify nitrogen provenance
Trace ammonia is common in laboratories, so isotope controls must rule out false positives.Use quantitative 15N2 controls and blanks to prove that measured ammonia came from supplied dinitrogen rather than contamination.
Recorded result: 2019 · A rigorous Nature protocol quantified contamination and confirmed lithium-mediated nitrogen reduction.
Next test: Apply quantitative isotope balance and blank controls to every claimed scale, rate or efficiency record.
Achieved
Send almost all the charge to ammoniaReach at least 90% Faradaic efficiency
This measures where the electric charge goes, not the cell's total energy use.Direct at least 90% of cathodic charge to verified N2-to-NH3 conversion in a rigorously controlled experiment.
Recorded result: 2022 · A 0.15 cm² nickel-wire experiment reported current-to-ammonia efficiency close to 100%.
Next test: Repeat at least 90% selectivity at industrially relevant rate, area and duration in one integrated cell.
Achieved
Keep a flow cell running for nearly two weeksSustain 300 hours of continuous flow
A longer run tests whether the electrolyte and electrodes survive beyond a short demonstration.Operate a flowing, verified N2-to-NH3 cell continuously for at least 300 hours without solvent failure or selectivity collapse.
Recorded result: Mar 2024 · A 25 cm² cell ran for 300 hours at 1 bar and room temperature with 64 ± 1% Faradaic efficiency.
Next test: Publish a mass-balanced 1,000-hour stack run including solvent, metal, proton-source and ammonia-recovery losses.
Open test
Make ammonia about ten times fasterReach 400 mA/cm² ammonia partial current
The strongest comparable 2024 result was 38.4 mA/cm² of ammonia-producing current; the 400 line is modeled, not achieved.Demonstrate at least 400 mA/cm² NH3 partial current, the rate used by a 2022 economic model for sub-$1/kg ammonia, without sacrificing efficiency or life.
Next test: An independently measured integrated stack must pair industrial rate with high energy efficiency, selectivity and long life.
The record behind the verdictThe record behind the verdict
Major milestones and smaller context events share one source-linked record. Scheduled targets are marked separately from recorded events.Milestones, smaller events and setbacks share one sourced record. Scheduled targets are marked separately from recorded events.
Event key
A lithium route waits
Recorded event: “Lithium route appears”.
Selectivity without trustworthy scale
Recorded event: “High-pressure selectivity reaches 59%”.
Verification before records
This record spans “False positives confronted” to “Gas diffusion raises the rate”.
From tiny cells to continuous flow
This record spans “Nearly all current selects ammonia” to “Continuous ambient-pressure flow”.
The energy and integration test
This record spans “Lithium's efficiency ceiling is quantified” to “Whole-cell energy use remains extreme”.
Additional records
This record spans “A proton shuttle improves output” to “Integrated-cell target comes due” and includes scheduled targets.
The data behind the verdictThe data behind the verdict
Read each measure with its units, conditions, uncertainty and source; targets remain distinct from observations.Read each chart with its conditions, limits and source. Future targets remain distinct from recorded results.
Gas-diffusion cathode; 35 ± 6% FE · 8.8 mA/cm² · 2020 · verification unspecified
View every data figure
Gas-diffusion cathode; 35 ± 6% FE · 8.8 mA/cm² · 2020 · verification unspecified
Independent records
Reported Faradaic efficiency linear scale · %
Conditionindependent device study; catalyst, cell and operating duration vary by source
Conditionindependent device study; catalyst, cell and operating duration vary by source
Record contextplotted conservatively below 100
Conditionindependent device study; catalyst, cell and operating duration vary by source
Conditionindependent device study; catalyst, cell and operating duration vary by source
Conditionindependent device study; catalyst, cell and operating duration vary by source
Reference values · not observed records
- Faradaic-efficiency targetFaradaic-efficiency target90 %target
Independent records
Continuous operating duration log scale · hours
Conditionindependent device study; catalyst, cell and operating duration vary by source
Conditionindependent device study; catalyst, cell and operating duration vary by source
Conditionindependent device study; catalyst, cell and operating duration vary by source
Independent records
Reported full-cell energy efficiency linear scale · %
Conditionindependent device study; catalyst, cell and operating duration vary by source
Conditionindependent device study; catalyst, cell and operating duration vary by source
Reference values · not observed records
- Full-cell energy-efficiency targetFull-cell energy-efficiency target60 %target
Each square = 2 %
Each square = 10 mA/cm²
Methods & conditions
Under the measurement.
The boundary of a measurement changes what it means.
Selectivity is not system efficiency
Method and conditions
Faradaic efficiency counts the fraction of charge that forms ammonia. It does not include the voltage penalty, gas preparation, solvent circulation, metal and proton-donor losses, separation or balance-of-plant loads. In the 2023 flow cell, 61% Faradaic efficiency corresponded to 13% full-cell energy efficiency.
Source notes
Technical notes and sources
Each note keeps its authored method, conditions and citations available for review.
Selectivity is not system efficiency
Faradaic efficiency counts the fraction of charge that forms ammonia. It does not include the voltage penalty, gas preparation, solvent circulation, metal and proton-donor losses, separation or balance-of-plant loads. In the 2023 flow cell, 61% Faradaic efficiency corresponded to 13% full-cell energy efficiency.
The lithium route carries a thermodynamic penalty
A 2025 analysis estimated a roughly 28% maximum energy efficiency for lithium- or calcium-mediated synthesis because electrodepositing either metal requires a very negative potential. It cites 60% as the US DOE technical-system target, so catalyst and reactor improvements alone may not close the route-level gap.
The 2024 frontier is grams, not tonnes
The 25 cm² continuous-flow experiment is important evidence of solvent and reactor durability, but it remains a laboratory cell. Its current density, area and production scale cannot be described as commercial ammonia output.
Nitrate-to-ammonia is a different problem
This dossier tracks reduction of molecular nitrogen, N2. Results starting from nitrate, nitrite or other activated nitrogen feedstocks are excluded because they do not demonstrate breaking the N≡N bond or sourcing nitrogen directly from air.
If the remaining tests pass.If the remaining tests pass.
Downstream capabilities remain conditional on results that are not yet in.These are possible next capabilities, conditional on results that are not yet in.
- PASSED · 201901 ↗Prove the ammonia came from nitrogen gasVerify nitrogen provenanceTrace ammonia is common in laboratories, so isotope controls must rule out false positives.Use quantitative 15N2 controls and blanks to prove that measured ammonia came from supplied dinitrogen rather than contamination.
- PASSED · 202202 ↗Send almost all the charge to ammoniaReach at least 90% Faradaic efficiencyThis measures where the electric charge goes, not the cell's total energy use.Direct at least 90% of cathodic charge to verified N2-to-NH3 conversion in a rigorously controlled experiment.
- PASSED · Mar 202403 ↗Keep a flow cell running for nearly two weeksSustain 300 hours of continuous flowA longer run tests whether the electrolyte and electrodes survive beyond a short demonstration.Operate a flowing, verified N2-to-NH3 cell continuously for at least 300 hours without solvent failure or selectivity collapse.
- OPEN TEST04 ↗Make ammonia about ten times fasterReach 400 mA/cm² ammonia partial currentThe strongest comparable 2024 result was 38.4 mA/cm² of ammonia-producing current; the 400 line is modeled, not achieved.Demonstrate at least 400 mA/cm² NH3 partial current, the rate used by a 2022 economic model for sub-$1/kg ammonia, without sacrificing efficiency or life.
Possible, if the open tests pass.
Distributed fertilizer production
This is a possible benefit only if distributed fertilizer production works safely, reliably and at useful scale.Potential benefit only if the stated use (Distributed fertilizer production) is demonstrated with evidence for safety, reliability, affordability and scale.
Flexible renewable chemical loads
This is a possible benefit only if flexible renewable chemical loads works safely, reliably and at useful scale.Potential benefit only if the stated use (Flexible renewable chemical loads) is demonstrated with evidence for safety, reliability, affordability and scale.
Lower-carbon nitrogen feedstocks
This is a possible benefit only if lower-carbon nitrogen feedstocks works safely, reliably and at useful scale.Potential benefit only if the stated use (Lower-carbon nitrogen feedstocks) is demonstrated with evidence for safety, reliability, affordability and scale.
Follow the evidence.Follow the evidence.
13 sources — every figure on this page traces to one.13 sources — every figure on this page traces to one.
- 01
Nature (2019) - rigorous isotope protocol
Read source ↗pubmed.ncbi.nlm.nih.govScope: Not recorded. Limit: Not recorded.
- 02
Nature Catalysis (2020) - gas-diffusion electrode
Read source ↗nature.comUsed on this pageAll 8 uses across 4 destinations
Scope: Primary publication named by Nature Catalysis (2020) - gas-diffusion electrode. Limit: The publication's measured scope does not establish downstream engineering or deployment claims.
- 03
Science (2021) - phosphonium proton shuttle
Read source ↗pubmed.ncbi.nlm.nih.govUsed on this pageAll 11 uses across 5 destinations
Scope: Not recorded. Limit: Not recorded.
- 04
Nature (2022) - near-100% current efficiency
Read source ↗nature.comUsed on this pageAll 7 uses across 5 destinations
Scope: Primary publication named by Nature (2022) - near-100% current efficiency. Limit: The publication's measured scope does not establish downstream engineering or deployment claims.
- 05
Science (2023) via DTU - continuous-flow cell
Read source ↗orbit.dtu.dkUsed on this pageScope: Not recorded. Limit: Not recorded.
- 06
ACS Energy Letters (2022) - economic performance targets
Read source ↗pubs.acs.orgUsed on this pageAll 6 uses across 5 destinations
Scope: Not recorded. Limit: Not recorded.
- 07
Nature (2024) - 300-hour continuous operation
Read source ↗nature.comUsed on this pageScope: Primary publication named by Nature (2024) - 300-hour continuous operation. Limit: The publication's measured scope does not establish downstream engineering or deployment claims.
- 08
Chem (2024) - interpretation of the 300-hour experiment
Read source ↗sciencedirect.comUsed on this pageScope: Not recorded. Limit: Not recorded.
- 09
ACS Energy Letters (2025) - energy-efficiency limit
Read source ↗pmc.ncbi.nlm.nih.govUsed on this pageAll 2 uses across 2 destinations
Scope: Not recorded. Limit: Not recorded.
- 10
ACS Applied Materials & Interfaces (2026) - whole-cell energy accounting
Read source ↗pubs.acs.orgUsed on this pageAll 6 uses across 4 destinations
Scope: Not recorded. Limit: Not recorded.
- 11
Vinnova (2026) - MACAROON project targets
Read source ↗vinnova.seUsed on this pageAll 7 uses across 5 destinations
Scope: Not recorded. Limit: Not recorded.
- 12
Timeline · High-pressure selectivity reaches 59%
Read source ↗tus.elsevierpure.comUsed on this pageAll 2 uses across 2 destinations
Scope: Not recorded. Limit: Not recorded.
- 13
Engineer note · Nitrate-to-ammonia is a different problem
Read source ↗orbit.dtu.dkScope: Not recorded. Limit: Not recorded.
Sources describe evidence. Inclusion is not endorsement.