[ materials ]
More hydrophilic GDL has higher performance at dry conditions due to the water retention ability of the membrane , while the performance is lower at saturated conditions due to excessive water flooding . More hydrophobic GDL exhibits higher performance at saturated conditions because it favours water removal , while it accelerates membrane dehydration at dry conditions . Balancing these three different functions plays an important role in the water management that needs to be carefully controlled in fuel cell operation . So , understand your materials – which brings me to the next point .
Lesson 2 : Know-how is not enough ; understand also the know-why ( structuretransport-processing relationships ). But it comes with difficulties .
I once asked myself what designing a catalyst ink for fuel cell MEA can learn from a Stradivarius violin ( or a Steinway piano , if you fancy ). Yes , companies can operate based on know-how alone ; the changes in the underlying technology are guided via learning from production experience and / or learning from the user experience – imagine baking bread or cake , or a company producing violins . Here is the thing : a lack of know-why is one reason why rivals face difficulties creating comparable products . What was found is that whereas the company can master producing one-of-a-kind Steinways or Stradivarius violins , they ( or others ) have not been able to find out why their recipes result in the creation of an excellent product .
Know-why becomes important because it :
• Creates a sustainable competitive advantage ;
• Allows to avoid errors ;
• Allows to be more responsive to possible changes / alterations required from the perspective of customer ’ s use case ;
• Gives a company and employees clarity about the processes , tasks , and relevant parameters , thus allows minimizing the unnecessary development direction ;
• Gives a field for future creative ideas for further development and innovation work environment .
What is know-why ? Learning by studying that involves controlled experimentation and simulation to understand the principles underlying the construction and functioning of the system , and interactions between components .
Let ’ s bring it home to the context of a fuel cell . Addressing the technical challenges in ensuring the effective fuel cell operation at high current densities , for the selected fuel cell design , has involved research for the optimization of mass , heat , and electricity flow in the fuel cell components . This is all towards the maximization of expensive platinum catalyst utilization to maximize the electrochemical reaction yield for fuel cell stack performance . Then , the question we may ask ourselves can be , what is the general approach towards next-generation fuel cell materials , and why ?
Let ’ s take the membrane as an example . In order to address the various needs of the market , membranes are coming in various thicknesses and different modifications . The general approach seen for fuel cell applications goas towards thinner membranes with lower equivalent weight ( EW ).
In the case of PEM , the underlying critical parameters for effective transport over sufficiently long period of time involve the permeability coefficient and proton conductivity , which are largely dependent on the chemical and mechanical properties .
In other words , to meet the electrolyte function in fuel cell operation , the membrane is expected to require the following specifications : i . High ionic conductivity , ii . Impermeability towards hydrogen and oxygen gases , iii . Low electrical conductivity , iv . Chemical ( oxidative ) stability , and v . Robust mechanical integrity at various operating conditions .
20 Hydrogen Tech World | Issue 15 | April 2024