“Understanding why existing hydrogen fuel cell prototypes degrade can pave the way for more durable fuel cells.” This is the premise of this new study coming from Australia.
Towards more durable, platinum-free fuel cells
Perhaps you remember the article we wrote 6 months ago about a team of researchers from the UNSW? Well, they have done again.
Professor Chuan Zhao, Dr Quentin Meyer and their team are focusing on enhancing the efficiency and affordability of hydrogen fuel cells to promote wider adoption of clean fuel. Hydrogen’s potential as a pivotal player in achieving a decarbonised future is hindered by slow commercialisation progress. The team is addressing challenges like the high cost and scarcity of key components such as platinum, commonly used as a catalyst in hydrogen fuel cells.
“Platinum is always going to be expensive, because there isn’t a lot out there,” says Prof. Zhao. “So, we need to explore alternatives, whilst also providing a quick and easy way to measure how well these new materials are working in hydrogen fuel cells.” Prof. Zhao’s recent study, featured in Energy & Environmental Science, introduces an innovative method for evaluating the durability and viability of cost-effective substitutes for platinum, aiming to advance hydrogen fuel cell technology.
Acting on the cost
Besides the “chicken and egg issue,” the cost of the catalyst also represents a major problem for the adoption of hydrogen fuel cells. One of the solution found is to use alternatives such as iron. By way of comparison, one kilo of platinum costs between $AUD 45,000 and $AUD 100,000 (between $USD 29,000 and 65,000). While one kilo of iron costs merely $AUD 0.1 according to Mr Liu. He emphasised that “a particular promising material is Iron-nitrogen-carbon, also known as Fe-N-C.”
Nevertheless, these novel platinum substitutes lack broad availability due to their inferior stability compared to platinum. They break down at a faster rate in hydrogen fuel cells. “While platinum-based fuel cells can last up to 40,000 hours (about 4 and a half years of continuing use), the iron-nitrogen-carbon materials can only run up to 300 hours (about 2 weeks of continuing use), in a best-case-scenario,” says Dr Meyer.
New methods to analyse fuel cells’ stability
To tackle existing challenges, the research team devised a method to understand the instability of catalyst materials compared to platinum. Using three novel methods, the team was able to figure out how stable a platinum-free fuel cell is and why. This approach can be easily adopted by other scientists to enhance their fuel cells and catalyst efficiency. Their findings revealed that around 75% of iron-based active sites become inactive within the initial 10 hours of fuel cell operation. Then carbon corrosion becomes the primary degradation mechanism. This detailed tracking of degradation mechanisms should enable the development of more stable materials and contribute to a more promising future for platinum-free catalysts in the field.
The team is now developing a catalyst where they are combining different metals to increase the stability of the catalysts. They are also focusing on ways they can increase the scalability of the low-cost, platinum-free hydrogen fuel cell catalyst.
Perhaps platinum-free fuel cells will power transport on the road in a few years time?
For more information, you can read the full press release here.
Photo: Front, from left to right: Shiyang Liu, Prof. Zhao, and Quentin Meyer. Back, from left to right: Dr Chen Jia, Shuhao Wang and Yan Nie. Supplied.
Reference: S. Liu, Q. Meyer (co-first author), C. Jia, S. Wang, C. Rong, Y. Nie, C. Zhao, Operando deconvolution of the degradation mechanisms of iron-nitrogen-carbon catalysts in proton exchange membrane fuel cells, Energy & Environmental Science, 2023, 10.1039/D3EE01166F
