Theory-Guided Experimental Strategies for Effective Materials Design in Fuel Cell and Electrolyzer
Authors: Jin Song , Lee Jong min , Park Minseon , Woo Seung-min , Choi Sung Mook , Seo Min Ho 
Published: December 2024

As is well known, the global movement toward carbon neutrality became legally effective as an internationally applicable law on November 4, 2016. This encouraged countries worldwide to proactively invest in the development of environmentally friendly energy conversion and storage technologies. Among various renewable energy, hydrogen stands out as an abundant and eco-friendly energy source. Therefore, the development of water electrolyzers and fuel cells is crucial for producing and utilizing green hydrogen, a key to advancing the hydrogen economy. To improve and commercialize these two specific electrochemical applications, the development of efficient electrocatalytic materials is essential.

Moreover, the rapid advancement in computer performance and software engineering since the introduction of Moore’s Law has enabled the development of effective materials by predicting catalytic activity and durability based on the unique electronic configurations of materials. It facilitates the design and validation of optimal catalysts and enables a faster and more accurate search for ideal catalytic materials. Especially, according to the Materials Genome Initiative (MGI) project, it is asserted that combining computational and experimental approaches can effectively discover, manufacture, and deploy advanced materials twice as fast and at a fraction of the cost compared to traditional methods. In recent energy research fields, the development of new energy materials based on theoretical mechanism validation and materials screening through computational methods, such as DFT calculations and molecular dynamics, is essential, not optional.

In this presentation, effective strategies for designing superior materials, developed through theory-guided experimental approaches, will be introduced with a focus on two specific electrochemical applications: the polymer electrolyte membrane fuel cell (PEMFC) and the alkaline electrolyte membrane water electrolyzer (AEMWE). The detailed two topics of the presentation are as follows.

As the first research topic, PEMFCs function by efficiently converting chemical energy into electrical energy through electrochemical reactions, producing clean byproducts such as water and heat. Their appeal lies in their high energy efficiency, environmentally friendly energy conversion, and low operating temperatures. However, the widespread adoption and commercialization of PEMFCs have been impeded by various issues related to scientific challenges, durability, and cost-effectiveness. For PEMFCs to achieve broad commercialization, enhancing the intrinsic activity and durability of electrocatalysts and catalyst layers (CLs) at high current densities is crucial. Therefore, two research strategies of nanostructure control and durable carbon materials for long-term PEMFC will be respectively introduced as follows: (1) The intrinsically superstable PtCo intermetallic nanostructure, validated by machine-learning-derived real-size simulations; and (2) The anti-carbon corrosive fluorine-doped graphene nanoribbon/carbon nanotube (F-GNR@CNT) composite as additives in the electrode.

As the second research topic, AEMWE presents a promising solution by combining the advantageous features of both alkaline water electrolysis (AWE) and proton exchange membrane water electrolysis (PEMWE) such as using non-precious metals in alkaline media and producing high-quality hydrogen at high-pressure. Although significant attention has conventionally been focused on the oxygen evolution reaction (OER) due to its complex multi-electron transfer process, the hydrogen evolution reaction (HER) is critical to the overall efficiency and cost-effectiveness of water electrolysis systems. This is because HER kinetics in alkaline media are approximately two to three orders of magnitude slower than in acidic media due to the Volmer step. Therefore, two research strategies for developing precious and non-precious electrocatalysts will be respectively introduced as follows: (1) The design of atomically ordered PtNi nanostructures for application in practical AEMWE systems; and (2) The introduction of a synergistic interfacial effect between Ni metal and CeO₂.

In summary, we have successfully designed superior electrocatalysts and durable carbon materials for green energy applications (PEMFC, AEMWE) through the combined study of computational and experimental approaches. For long-term PEMFCs, the highly ordered PtCo intermetallic nanostructure demonstrated robust stability in acidic conditions during the oxygen reduction reaction (ORR). Furthermore, the addition of F-GNR@CNT to the Pt/C cathode improved durability by enhancing carbon corrosion resistance and optimizing water management. For high-performance AEMWE, intermetallic PtNi nanostructures were introduced to intrinsically enhance catalytic activity and durability. Additionally, Ni/CeO₂ electrocatalysts, benefiting from a synergistic interfacial effect, were integrated into an industrial-scale durable AEMWE system with an active surface area of 64 cm².

Finally, we definitely believe that the synergy between computational validation and experimental skills can be highly effective and productive in the field of energy research.

This work has been supported by the National Research Foundation of Korea (NRF) grant funded by the Ministry of Science and ICT in the Republic of Korea (MSIT) (NRF-2022R1A2C2093090) and was supported by the Nano & Material Technology Development Program through the National Research Foundation of Korea(NRF) funded by Ministry of Science and ICT(RS-2024-00409675).