(written by: Willy Yanto Wijaya)
Like the heat pump, fuel cell is an important technology in the energy utilization systems. Before the concept of fuel cell was invented, people utilized the chemical energy to be combusted and then this heat was converted into electricity through the turbine-generator system. Fuel cell, on the other hand, converts this chemical energy directly to the electricity energy thus shortening the energy conversion processes; and this means less exergy loss will occur. It can be said that fuel cell has avoided the irreversibility otherwise occurred in chemical-heat-electricity conversion processes. In this sense, intuitively we could expect that fuel cell will give a very high efficiency. However, why until now the efficiency of fuel cell is still in the range of 50-60%, just a little higher than the efficiency of power plant combustion system?
Fuel cell system is not without problems. Several to mention are the cost, durability, reactivity, losses and other thermal, water management and technical issues. To pick up a case, research has been done concerning the finding of alternatives to Pt catalyst that is expensive. However, to find suitable material to replace Pt is not an easy matter. This requires the knowledge and understanding of material properties, molecular interaction and various electro-chemical-physics parameters. The same case also happens to the questions such as: why the reactivity is slow and how to prolong the durability of membrane. These all require research in inter-disciplinary fields.
We can say that our fundamental understanding is still not “complete”, even still not “sufficient”. Like the Shirakawa Sensei story of Nobel Prize; he said that his discovery of the new material was due to the mistake of his student. His student added the catalyst 1000 times of the intended amount. This implies that actually we still don’t know very well the chemical reactions. There are so many chemical and physical parameters that work together in the actual system in the nature: the properties of material; aspect of particle geometry; various chemical substances; physical parameters such as temperature, pressure, magnetic field; etc.
Possibly we can view all these one-another interactions of these parameters like the sand pile. What we see are only average-statistical resultant of the deeper microscopic mechanisms. It is like the tiny bit of sand on the peak of the pile, supported by several tiny bits below. It is possibly the reasons why people in medicine/biology field can only memorize the outer macroscopic phenomena, since the living organism systems are so complex if they dig deeper into the microscopic mechanisms “sand pile”. This could be the reason why Roger Penrose thought that the realm of Biology can be reduced into the realm of Chemistry and further reduced into the realm of Physics.
Therefore, I think that attempts to keep documentation of each chemical-physical parameter and its interaction with myriad of other parameters are necessary. Of course, there will be enormously huge amount of data, interactions, and possibilities. Nevertheless, if this huge amount can be documented well, they can be more conveniently assembled and better research can be conducted. To connect to the fuel cell, right now, we can see many researchers are attempting to use alternative materials, such as alternative for Pt catalyst; NaBH4 as the fuel for fuel cell, etc. Of course, to determine the choice, understanding about substance/material parameters is indispensable. Without this, only the “brute-force” efforts (trial and error) could be done, and most of these efforts will only die away since the probabilities of the choices are so enormous like the probabilities of the “Hanoi Tower” puzzle.
Fig. Schematic of a fuel cell car.