Potentiostats And Their Role in Green Hydrogen Systems 

The road to a carbon-free future is complicated and requires the development of alternative fuels which are sustainable and rely on renewable energy sources.  Currently, 80% of industry’s energy needs are met by fuel combustion and switching from fossil fuels is imperative. Governments and private companies are investing heavily in different technologies to achieve these goals. Green hydrogen has emerged as a promising solution for reducing reliance on fossil fuels in the quest to decarbonize the world’s industries.   

What is Green Hydrogen 

Green hydrogen is produced through the electrolysis of water, a process that splits water molecules (H₂O) into hydrogen (H₂) and oxygen (O₂) using electricity generated from renewable sources such as wind, solar, and hydro power. Unlike other methods of producing hydrogen, green hydrogen is entirely carbon-free, making it an attractive alternative for a range of applications, including transportation, industrial processes, and energy storage. 

Electrolyzer vs Fuel Cells. 

Electrolyzers and fuel cells are complementary electrochemical devices that are involved in the conversion of energy. An Electrolyzer converts electrical energy into chemical energy by splitting water into hydrogen and oxygen (electrolysis). It has two electrodes: an anode and a cathode, separated by an electrolyte. When a voltage is applied, water (H₂O) is split into oxygen (O₂) at the anode and hydrogen (H₂) at the cathode. 

A Fuel Cell converts chemical energy into electrical energy, by using hydrogen and oxygen to produce electricity, water, and heat. It also has two electrodes: an anode and a cathode, separated by an electrolyte. Hydrogen is supplied to the anode, and oxygen (usually from air) is supplied to the cathode. Hydrogen undergoes oxidation at the anode, releasing electrons and protons. The electrons travel through an external circuit, creating electrical power, while the protons move through the electrolyte to the cathode, where they combine with oxygen to form water. 

High Power Potentiostats for Green Hydrogen R & D 

A great deal of research and development efforts are underway to generate and use green hydrogen. Comprehensive testing of electrolyzer and fuel cell performance requires the use of a high-power potentiostat or power supply. Compared to most power supplies, high power potentiostats are more advantageous for these applications because they can control and measure current and voltage with better accuracy. In addition, modern potentiostat also incorporate functions that allow for complex test procedures to be developed including pulse trains.  Some high power potentiostats can measure the impedance of operating electrolyzers without the necessity for additional equipment.  This reduces complexity and increases the value of the potentiostats.  The key features of a high power potentiostat are: 

1. High current and voltage handling to enable testing of larger scale systems 

2. Accurate and Precise Control and Measurement essential for understanding kinetics and mechanisms of the electrolysis reactions 

3. Advanced Data Acquisition and Analysis to collect and analyze large quantities of data 

Applications of High-Power Potentiostats in Green Hydrogen Research

Electrolyzer and Fuel Cell Development

One of the primary applications of high-power potentiostats in green hydrogen R&D is the development and optimization of electrolyzers and fuel cells. Researchers use potentiostats to study the electrochemical behavior of different electrode materials, separators and coatings, which can significantly impact the efficiency and durability of electrolyzers and fuel cells.¹  Cyclic Voltammetry can be used to optimize electrode designs by understanding the redox behavior of electrode materials and the kinetics of electrochemical reactions. Long-term stability of electrodes and electrolytes can be assessed, monitoring degradation or performance loss over time. 

By experimenting with various materials and configurations, scientists aim to develop electrodes that require less energy to produce hydrogen, thus improving the overall efficiency of the electrolysis process. Potentiostats enable the calculation of the overall energy efficiency of the electrolysis process, guiding improvements in system design and operation.²  Potentiostats help optimize the conditions for water splitting, ensuring maximum hydrogen production efficiency.  

Potentiostats can be used to generate polarization curves, which provides information about the overall performance of the fuel cell, including its efficiency and power output. Analyzing the impedance of the fuel cell components helps with identifying issues such as charge transfer resistance, mass transport limitations, and ohmic losses. Potentiostats help in understanding degradation mechanisms by monitoring changes in electrochemical behavior over time and identifying strategies to enhance the longevity of fuel cells.

Catalyst Research

Catalysts play a crucial role in reducing the energy required for electrolysis. High power potentiostats are used to evaluate the performance of different catalytic materials under diverse conditions.³ Potentiostats are used to evaluate the performance of electrocatalysts by measuring the current response to an applied potential. This helps in identifying efficient catalysts for the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). Researchers can measure the overpotential (the extra voltage required to drive the reaction) and the stability of catalysts over time. This information helps in identifying and developing more efficient and robust catalysts that can lower the cost of green hydrogen production. Potentiostats are used to assess the performance of electrocatalysts for the oxygen reduction reaction (ORR) and hydrogen oxidation reaction (HOR) in fuel cells. 

Fuel Cell Testing 

In addition to hydrogen production, high-power potentiostats are also used in the development of hydrogen fuel cells, which convert hydrogen back into electricity. Fuel cells are critical for applications such as zero-emission vehicles and portable power systems. Potentiostats enable researchers to test the performance of fuel cells under different loads and operating conditions, helping to improve their efficiency and longevity.⁴ Potentiostats can be used to test the performance of individual electrochemical cells, assessing their efficiency, durability, and response to different operating conditions. Potentiostats can also evaluate the performance of cell stacks, ensuring uniform operation and identifying any issues related to scaling up from single cells to full systems. Potentiostats are employed to perform accelerated stress testing protocols to evaluate the long-term durability of fuel cell materials under simulated operating conditions. 

Conclusion

Green hydrogen represents a cornerstone of the transition to a sustainable energy future. The use of high-power potentiostats in R&D is essential for unlocking the full potential of hydrogen technologies. By enabling precise control and measurement of electrochemical processes, these instruments help researchers develop more efficient and cost-effective solutions for hydrogen production and utilization. As we continue to innovate and integrate green hydrogen into our energy systems, the contributions of high power potentiostats will be instrumental in shaping a cleaner, more sustainable world. 

References

1. Kim, Hoyoung, et al. “Non-precious metal electrocatalysts for hydrogen production in proton exchange membrane water electrolyzer.” Applied Catalysis B: Environmental, vol. 206, June 2017, pp. 608–616, https://doi.org/10.1016/j.apcatb.2017.01.074  ︎
2. Siritanaratkul, Bhavin, et al. “Improving the stability, selectivity, and cell voltage of a bipolar membrane zero‐gap electrolyzer for low‐loss Co2 Reduction.” Advanced Materials Interfaces, vol. 10, no. 15, 18 Apr. 2023, https://doi.org/10.1002/admi.202300203 ︎
3. Piñeiro García, Alexis, et al. “Benchmarking molybdenum-based materials as cathode electrocatalysts for proton exchange membrane water electrolysis: Can these compete with pt?” ACS Sustainable Chemistry & Engineering, vol. 11, no. 20, 5 May 2023, pp. 7641–7654, https://doi.org/10.1021/acssuschemeng.2c07201 ︎
4. Kim, Hayoung, JaeHyuck Lee, et al. “Characterization of direct-ammonia solid oxide fuel cells (DA-sofcs) at 650–750 °C in a single-repeating unit stack: Effects of metallic components and residual ammonia.” International Journal of Hydrogen Energy, vol. 68, May 2024, pp. 1312–1321, https://doi.org/10.1016/j.ijhydene.2024.04.250 ︎