Alkaline Fuel Cell (AFC)
Alkaline Fuel Cells (AFCs) are an established fuel cell technology that utilise an alkaline electrolyte to generate electricity. AFCs require a steady stream of pure hydrogen and oxygen or air for the electrochemical reaction to occur. Hydrogen oxidation occurs at the anode, producing water and releasing electrons, which travel through an external circuit, creating an electric current.
The electrons return to the cathode, where they reduce oxygen, in the presence of water, to produce hydroxide ions. A schematic of the AFC technology is illustrated in Figure X. The alkaline electrolyte (typically potassium hydroxide) facilitates the exchange of hydroxide ions between the anode and the cathode. AFCs provide high electrical efficiency and have been used in various application, such as stationary power generation and space missions. If the green hydrogen fuel is utilised, they produce power with virtually zero emissions.
Government incentives and a global shift towards a zero-emission economy have caused the AFC market to gain momentum, especially given its maturity. The current AFC market is valued at £81.4m, with an expected growth to £292m by 2031 (Market research Intellect). Despite a substantial expected growth in market share, AFCs only take up a minute share of the global fuel cell market, owing to some critical challenges that need to be addressed to boost investor confidence. The biggest challenge with AFCs is their sensitivity to carbon dioxide, which reacts with the alkaline potassium hydroxide electrolyte to produce potassium carbonate, reducing conductivity and increasing the rate of degradation. This sensitivity to carbon dioxide requires an additional air purification system, which significantly increases the complexity and cost of the system. The presence of a strong alkaline liquid electrolyte poses other challenges besides carbon dioxide poisoning, such as leakages which leads to corrosion and degradation, reducing efficiency and lifespan. These challenges have prevented large-scale deployment, as significant capital investment is required for the control and management of air purification systems, material durability, and electrolyte leakage related corrosion
Challenges Revealed Through Literature Review
- Catalyst agglomeration causes uneven wear leading to decreased performance and endurance
- Electrolyte leakage thhrough the gas diffusion layer
- Adsorption of CO2 leads to formation of carbonates, severly limiting the performance
- Corrosion Ohmic losses from inefficient current collection severly limits current density
- Anion exchange ionomers that are chemically and structurally stable at cell temperatures of 80 °C or above
- AEMs 10 μm thick, thinner, that are chemically and structurally stable at cell temperatures of 80 °C or above
- PGM-free anode catalysts (or possibly anode catalysts of ultra-low PGM loading) Advanced hydroxide-conducting ionomers using alternative cationic functional groups and tethers that minimize chemical instability and prevent formation of surface barriers by co-adsorbed ions
- Advanced hydroxide-conducting ionomers of better water uptake characteristics aiming to achieve high conductivity in contact with lower water activities, as well as controlled swelling in contact with liquid water at relevant cell temperature
- Advanced hydroxide-conducting composite membranes employing a fine inert mesh as support for the active ionomer
- Further non-PGM catalyst development with high HOR activity maintained at anode potential above 0.1 V versus RHE
- Further non-PGM catalyst development targeting cell performance stability to 5000h in well-prepared catalyst layers
- Further optimization of catalyst layer composition and preparation techniques, including ionomer dispersion control, targeting higher performance and better stability
- Innovative approaches to effective water management in AEMFCs, covering the full operating range of the cell, without the use of an external water supply
- Creating effective cell designs with non-PGM catalysts able to match or surpass the performance of the PGM benchmark
- Few large-scale (100 cm²) AEMFCs have been built, hence further efforts are required to face the optimisation challenges on the system level.
- Overall, streamlined design strategies are required for catalysts, ionomer, electrolyte and miscellaneous electrode components to avoid a mismatch of electrochemical properties.
Academic Capability Mapping
Word cloud
The word-cloud of the primary and secondary keywords is presented for the Alkaline Fuel Cell (AFC) technology. These keywords were used as the input to Scopus for the purpose of the Academic Capability Mapping. The analysis underscores key research areas like ion exchange, electrocatalysis, and alkaline stability, while highlighting reliance on Platinum.
Documents by Country
The number of papers published worldwide pertaining to Alkaline Fuel Cells since the year 2000, divided into three decades. Only the top 10 countries are displayed. It is interesting to note that while the AFC technology is mature in the UK, the UK ranks at number 7 in further research, indicating a lack of further research commitment towards performance optimisation and cost reduction.
Documents by Author (2000 – 2025)
Prominent UK academics and their affiliation is showcased. The y-axis represents the H-index of the authors, while the x-axis illustrates the number of papers published. It can be clearly seen that while the UK authors may have high H-index’s, the number of papers they have published in the field of AFC are minute, compared to their counterparts globally.
Documents by Affiliation
The number of papers published by affiliation in the UK since the year 2000 are showcased. The University of Surrey leads the way with the most publications, closely followed by Newcastle University. The figure specifically highlights the top 10 UK institutions in the field of Alkaline Fuel Cells, providing a definite ranking list of universities with excellent expertise in the AFC technology.
Alkaline Fuel Cell (AFC) – Delphi Survey Analysis
Participant Identifiers
Industry Collaboration
Confidence Level
Country Affiliation
Key Performance Indicators
Key technical target predictions were provided by the participants, expected to be achieved by 2030.
Challenges
The participants were provided with several options and were asked to rank these options from 0 (least critical) to 6 (most critical). They were also provided with a text option to suggest additional challenges.
Additional Stack Challenges
- Membrane
- Catalyst
- Electrolyte
- Stability
- Water management
Additional Key Challenges
- Durability
- Catalyst cost
- Thermal management
- Water management
- Membrane Electrode Assembly
Alkaline Fuel Cell System Integration
- Balance the Intermittency of renewable electricity
- Peak shaving of the electricity grid
- Grid backup and resilience in case of outage
- Microgrid construction and emergency power response
- Combined heat and power for residential applications
- Waste-to-Energy applications
- Industrial waste heat reutilistion for steam generation
- Fully supply systems
- The durability when ‘free’ air is used at the cathode
- Valves and sensors
- Electrolysers may interact in case of direct fuelling
- Air purification system to remove CO2 in the air
- Portable and backup power systems
- Micro-grid energy storage systems