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For trucks and heavy-duty vehicles that travel long distances, traditional battery systems can be inadequate due to their charging limitations. Hydrogen fuel cells present a promising alternative, allowing for quick refueling similar to gasoline while offering cleaner energy solutions.
Recent developments by researchers at UCLA indicate significant advancements in extending the lifespan of these fuel cells, paving the way for sustainable long-haul trucking to become increasingly feasible.
Led by Yu Huang, a professor at the UCLA Samueli School of Engineering, the research team has crafted a new catalyst design that could potentially double the expected lifespan of fuel cell catalysts to an impressive 200,000 hours. This figure greatly exceeds the U.S. Department of Energy’s target for fuel cell longevity by 2050. The findings were detailed in a study published in Nature Nanotechnology. This breakthrough is crucial for encouraging the widespread adoption of fuel cell technology in heavy-duty vehicles like long-haul trucks.
Despite comprising only about 5% of cars on the roads, medium- and heavy-duty trucks account for nearly 25% of greenhouse gas emissions from automobiles, according to federal data. This makes these vehicles an optimal sector for implementing polymer electrolyte membrane fuel cell technology.
Fuel cells present significant advantages over batteries, particularly their lighter weight, which translates to less energy expenditure for moving vehicles. With a projected output of 1.08 watts per square centimeter, these new fuel cells can deliver comparable performance to traditional batteries that may weigh eight times more. Such efficiency is especially significant for heavy-duty vehicles, which not only endure substantial cargo loads but are also inherently heavier. Moreover, establishing a nationwide hydrogen refueling infrastructure may require a lower investment compared to building extensive electric vehicle charging networks.
These fuel cells convert hydrogen’s chemical energy into electricity, emitting only water vapor, which enhances their appeal as a cleaner transport solution. However, the slower chemical reactions needed for energy conversion have necessitated catalysts to improve efficiency.
Historically, platinum-alloy catalysts have offered superior performance, but they face challenges, such as the leaching of alloying elements over time, which reduces effectiveness. This degradation accelerates under the intense voltage cycles demanded by heavy-duty vehicle operations.
To mitigate this issue, the UCLA team has ingeniously designed a resilient catalyst structure that protects against the typical deterioration found in alloy systems.
The researchers embedded ultrafine platinum nanoparticles in graphene pockets, a remarkable material known for being the thinnest yet incredibly strong and conductive. The nanoparticles are further secured within a porous carbon structure known as Ketjenblack, creating a “particles-within-particles” framework that enhances stability while maintaining essential catalytic activity.
“Heavy-duty fuel cell systems have to endure harsh operating conditions over extended periods, making durability a critical challenge,” Huang remarked. “Our pure platinum catalyst, enhanced with a graphene protection mechanism, addresses the weaknesses of conventional platinum alloys by preventing the leaching of alloying materials. This advancement ensures long-lasting activity and robustness under typical long-haul conditions.”
The new catalyst demonstrated a minimal power reduction of less than 1.1% after undergoing a rigorous test simulating 90,000 square-wave voltage cycles, which equates to years of on-road use, where a loss of only 10% is generally deemed impressive. Such promising results suggest that the lifespan of these fuel cells could exceed 200,000 hours, far surpassing the DOE’s goal of 30,000 hours for heavy-duty proton exchange membrane fuel cells.
By successfully overcoming the critical challenges of catalytic performance and longevity, the novel catalyst design from UCLA brings significant promise for the future of hydrogen-powered heavy-duty vehicles. This advancement is vital for cutting emissions and enhancing fuel efficiency in a sector that constitutes a major portion of transportation energy consumption.
The recent study builds on prior achievements from the same team, which created a fuel cell catalyst for light-duty vehicles that achieved a lifespan of 15,000 hours, nearly doubling the DOE’s 8,000-hour objective.
The research was spearheaded by UCLA Ph.D. graduates Zeyan Liu and Bosi Peng, who were guided by Huang. Their research group specializes in developing nanoscale materials for fuel cell catalysts. The study also includes contributions from Xiaofeng Duan, a professor at UCLA, and Xiaoqing Pan from UC Irvine. Both Huang and Duan are affiliated with the California NanoSystems Institute at UCLA.
Additional contributors include Yu-Han “Joseph” Tsai and Ao Zhang from UCLA, along with Mingjie Xu, Wenjie Zang, XingXu Yan, and Li Xing from UC Irvine.
The technology has been patented by UCLA’s Technology Development Group.
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