Why ammonia could become an important fuel for future fuel-cell systems
Ammonia is more than a hydrogen carrier. Direct electrochemical conversion could eventually create another pathway from stored chemical energy to electricity.
The transition to low-carbon energy is not only a question of how electricity is generated. It is also a question of how energy can be stored, transported and converted when batteries or direct grid connections are not ideal.
Hydrogen is often discussed as one answer. But hydrogen also introduces difficult storage and distribution requirements, particularly when high-pressure gaseous storage is involved.
Ammonia (NH₃) offers a different possibility.
It is already manufactured, transported and handled at industrial scale. More importantly for fuel-cell research, each ammonia molecule contains hydrogen while containing no carbon.
The conventional route is to treat ammonia as a hydrogen carrier: crack NH₃ into hydrogen and nitrogen, purify the gas and feed the hydrogen into a fuel cell.
But another pathway is possible.
What if ammonia could be used directly?
A Direct Ammonia Fuel Cell, or DAFC, attempts to convert the chemical energy of ammonia electrochemically without first using a separate external hydrogen cracker.
In an anion-exchange-membrane architecture, ammonia is supplied to the anode while oxygen or air is supplied to the cathode. The electrochemical system is designed to generate:
electricity + nitrogen + water
This potentially removes one complete conversion subsystem from an ammonia-to-power architecture.
But removing the cracker does not mean the engineering becomes simple.
Why ammonia is interesting as an energy carrier
Ammonia has several characteristics that make it worth investigating.
- It already has a substantial global industrial supply chain.
- It can be stored as a liquid at considerably more manageable conditions than compressed hydrogen.
- It contains no carbon atoms, so the molecule itself does not produce CO₂ during ideal electrochemical conversion.
- As green-ammonia production expands, it may provide a pathway between renewable electricity and applications that need stored chemical energy.
These advantages, however, do not automatically make ammonia an ideal vehicle fuel.
Toxicity, materials compatibility, leakage detection, storage, exhaust treatment and safe handling must all be engineered carefully.
Any realistic ammonia-energy system therefore has to treat safety as a primary design discipline rather than an afterthought.
Direct ammonia versus ammonia-to-hydrogen
There are two fundamentally different routes.
Route 1: ammonia cracking
The ammonia first becomes a hydrogen carrier. This can benefit from established hydrogen fuel-cell technology, but introduces additional equipment for cracking, thermal management and potentially gas purification.
Route 2: direct ammonia fuel cell
Here, ammonia participates directly in the electrochemical system. The architecture can potentially become simpler, but the electrochemistry is considerably more challenging.
This is the pathway H2ONE is investigating.
The difficult part is electrochemistry
Direct ammonia fuel cells face several known technical challenges.
- Ammonia oxidation kinetics can limit anode performance.
- Membrane conductivity contributes to internal resistance.
- Ammonia crossover can reduce utilisation and influence cathode behaviour.
- Water management affects membrane and electrode operation.
- Mass transport becomes increasingly important as current density and active area increase.
- Durability ultimately determines whether laboratory performance can become useful engineering performance.
These are not secondary research questions. They determine whether DAFC technology can progress from a laboratory cell to a practical power system.
Small-cell success is only the beginning
At H2ONE, our development programme begins with measured cell-level electrochemistry.
The current experimental reference is a 25 cm² laboratory DAFC cell, with a measured peak power density of approximately 0.12 W/cm² at around 0.27–0.30 A/cm² and ≈70 °C. Experimental See the polarisation data →
But a commercial power system cannot be created by simply multiplying this performance by a larger area. A large cell introduces:
That is why scale-up is an engineering programme, not an arithmetic exercise.
Simulation helps, but hardware decides
Modern engineering allows many design options to be evaluated digitally before expensive hardware is produced.
- Reduced-order models can investigate electrochemical behaviour.
- CFD and multiphysics models can examine reactant distribution, temperature and current density.
- Structural models can evaluate compression, contact pressure and end-plate deformation.
The value of simulation is therefore significant. But our philosophy is simple:
Simulation reduces hardware iterations. It does not replace physical validation.
Every important scale-up assumption eventually has to meet a physical test.
Where commercial mobility fits
H2ONE is initially investigating commercial three-wheelers. This application is interesting because the propulsion architecture is already electric:
Instead of redesigning the drivetrain, one development pathway is to change the upstream energy system:
A small transient-energy buffer, connected in parallel on the DC bus, can support short-duration power demand and regenerative braking.
The concept is still under engineering development and requires extensive validation in performance, safety, durability, packaging and regulation. But it provides a very clear research question:
Can direct ammonia electrochemistry become a practical primary energy source for high-utilisation electric commercial mobility?
That is the question H2ONE is working to answer.
The future will likely need more than one energy technology
Battery electric vehicles will continue to play a major role. Hydrogen systems will continue developing. Synthetic fuels, biofuels and other electrochemical technologies will also evolve.
Ammonia should therefore not be presented as a universal replacement for these technologies. The more useful question is:
Where might ammonia's storage and logistics characteristics justify the additional engineering required to use it safely?
High-utilisation commercial mobility, distributed power, marine applications and other energy-intensive use cases may eventually provide some answers. But those answers must come from evidence.
H2ONE's approach
We are building the evidence one engineering gate at a time:
H2ONE welcomes discussions with automotive OEMs, fuel-cell researchers, universities, ammonia-industry partners, engineering companies and mobility operators interested in exploring the future of direct-ammonia power.
This article discusses emerging technology and H2ONE's engineering perspective. Development concepts are not validated product performance unless explicitly identified as measured.