What are fuel cells? A fuel cell uses the chemical energy of hydrogen or other fuels to cleanly and efficiently produce electricity. Fuel cells, unlike batteries, do not run down or need recharging. They produce electricity and heat as long as fuel is supplied. A fuel cell consists of two electrodes—a negative electrode (which is called the anode) and a positive electrode (which is called the cathode) and an electrolyte. You can imagine their positions like a sandwich. The electrode is the bread and the electrolyte is the cheese or the peanut butter & jelly. A fuel (in this case hydrogen) is sent to the anode, and plain old air is sent to the cathode. In a hydrogen fuel cell, a catalyst at the anode separates hydrogen molecules into protons and electrons (cause that’s all the majority of hydrogen is), which take different paths to the cathode. The electrons go through an external circuit, creating a flow of electricity. The protons travel through the electrolyte to the cathode, where they combine with the oxygen from the air and the electrons to produce water and heat.
Fuel cells are categorised based on the electrolytes that they use. This classification helps us identify the nature and types of chemical reactions that would take place, the kinds of inhibitors and catalysts to be used along with the required conditions, like temperature, fuel and much more. This classification also helps us in choosing the right cell, be it for a large power station or just to power your laptop. The different types of fuel cells could be utilised for various fields like space, military, transportation, vehicles and automobiles, electric utility and auxiliary power.
The advantages of fuel cells are that they require low temperatures, provide a variety of stable components to reduce cost, have high efficiency, are suitable for CHP (Combined heat and power or cogeneration) and also allow quick start-up and load following.
Even though fuel cells are cost-effective, provide variety and are quite efficient, they pose certain challenges, like expensive catalysts and are subject to impurities. Some types of fuel cells also have low power density and require a long start-up time.
As humanity continues to progress at an exponential rate, it is time for us to discover newer ways to replace or at least find alternatives to fossil fuels and natural gas. Hydrogen-powered locomotives and fuel cells could act as great alternatives to gasoline and petroleum products like kerosene and diesel. Cars that utilize hydrogen-powered cells are efficient, clean and much faster to refuel than electric cars. In fact, hydrogen cars also offer greater ranges than electric vehicles.
On the other hand, some experts say that hydrogen fuel cells have bad theoretical and practical efficiency and believe that Hydrogen storage is inefficient, energetically, volumetrically and with respect to weight. Also, hydrogen as a fuel is four times as expensive as gasoline and the methods used to get large quantities of hydrogen are not 'cleaner' than gasoline. It is now our choice to decide whether fuel cells in the field of automobiles are a boon or a bane.
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