Added to the Mix: Making Polymer Electrolyte Membrane Fuel Cells More Durable
작성자. External Relations Team
Scientists develop degradation-mitigating additives that vastly extend the lifespan of Nafion-based fuel cells.
Polymer electrolyte membrane fuel cells could soon become a green alternative to the internal combustion engine widely used in transportation. However, Nafion, the most promising membrane material to date, degrades rapidly during use. Now, scientists at DGIST, Korea, have developed a degradation-mitigating additive that makes Nafion membranes significantly more durable. Their approach paves the way to a more sustainable society with less carbon emissions and air pollution.
Professor Sangaraju Shanmugam standing next to Mr. Maxwell Tsipoaka, Master’s degree student, at DGIST’s Energy Engineering laboratory. ⓒDGIST
With greenhouse gas emissions already soaring and projected to increase in upcoming years, researchers worldwide are frantically looking for viable alternatives to one of the main culprits: the internal combustion engine widely used in transportation. A promising candidate that’s on the brink of technological readiness is the polymer electrolyte membrane fuel cell (PEMFC). These devices are electrochemical cells that generate electricity through reactions that consume hydrogen and produce only water as a byproduct. In essence, PEMFCs are energy converters that can be deployed within vehicles and other devices compatible with hydrogen as fuel.
Despite their huge potential, technical challenges still hinder the widespread adoption of PEMFCs. Nafion, one of the best materials available for the polymer electrolyte membrane of PEMFCs, degrades rather rapidly when dry and at high temperature; these are, sadly, Nafion’s normal operating conditions. Fortunately, a team of scientists led by Professor Sangaraju Shanmugam from Daegu Gyeongbuk Institute of Science and Technology (DGIST), Korea, have recently reported an efficient way to tackle this problem.
They theorized that the degradation of Nafion could be drastically reduced if the very chemical mechanisms behind this degradation could be stopped or mitigated right at the membrane. To achieve this, the scientists crafted an additive out of cerium–titanium oxide nanoparticles, which combat dryness by absorbing water and prevent degradation by capturing defect-inducing chemical radicals like hydride (OH−). The nanoparticles were dispersed in the Nafion membrane both loosely (on their own) and uniformly contained within carbon nanofibers.
By introducing this novel additive to the fuel cell’s electrolyte, its degradation was reduced by about two orders of magnitude and its durability increased to over 400 hours, surpassing that of other state-of-the-art Nafion membranes! “Our findings validate the rationale of combining Nafion with degradation-mitigating additives as a way to extend the lifespan of the fuel cell’s membrane,” remarks Shanmugam, “This approach should help minimize or even eliminate the current costs of membrane humidification, taking us yet another step closer to a green energy economy.”
Shanmugam and his team believe that the adoption of PEMFCs as energy conversion devices for hydrogen derived from clean sources will have a tremendously positive impact in many regards. “The problems associated with petroleum-based energy consumption, including air pollution, greenhouse-gas emissions, and economic dependence on petroleum, can be reduced drastically by switching from the internal combustion engine to PEMFCs,” explains the Professor. Their study was approved for publication in the Sustainable Chemistry and Engineering journal of the prestigious American Chemical Society, and a patent application was successfully filed as well. Let us hope these confident strides towards sustainable technologies will help us secure a better future for ourselves and the generations to come.
The emissions of internal combustion engines accelerate global warming and pollute the air, causing health problems and millions of premature deaths. / Photo courtesy: Amir Hosseini at Unsplash.com
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For more information, contact: Sangaraju Shanmugam, Professor
Department of Energy Science & Engineering
Daegu Gyeongbuk Institute of Science and Technology (DGIST)
Maxwell Tsipoaka, Md. Abdul Aziz, and Sangaraju Shanmugam, "Degradation-Mitigating Composite Membrane That Exceeds a 1 W cm–2 Power Density of a Polymer Electrolyte Membrane Fuel Cell Operating Under Dry Conditions", ACS Sustainable Chemistry & Engineering, February 9th, 2021, online published.