A Hydrogen fuel Cell that is capable of producing a voltage of between 0.6 V to 0.7 V at full rated load has an electric current that can be used in driving electrical devices. This electric current that is referred to as the load is achieved through a number of chemical reactions that involve other reactants Hydrogen and Oxygen as the main components.
Hydrogen fuel cell – basic introduction
A fuel cell basically is a cell that converts source fuel into electrical power in the form of a current through reactions that involve a fuel and an oxidant. The hydrogen electrochemical cell uses hydrogen as its fuel and oxygen from the air as the oxidant. This means that the difference between the conventional battery and the hydrogen fuel cell is that the latter consumes a reactant from an external source that has to be replenished unlike the battery, which operates under a thermodynamically closed system.
Basic working methodology
Two reactions happen at the three segments of the fuel cell; the result of the reactions is an electric current and water or carbon dioxide as the fuel is consumed. The first chemical reaction takes place at the first segment (the anode), here, a catalyst oxidizes the fuel to create a positive ion and a negative electron. Since the second segment (the electrolyte) can only allow the ions to pass through it to the third segment (the anode), the electrons pass through a wire to create the anticipated electric current. At the cathode, the electrons reunite with the ions under the oxygen component to create carbon dioxide and pure water.
Most important features
Here are some of the important features of a hydrogen cell:
- The catalyst that is usually used at the anode is fine platinum powder that facilitates the breakdown of the hydrogen fuel into electrons and ions. It acts by diffusing the hydrogen and dissociating it into protons and electrons, but as the electrons are from the anode to the cathode to react with oxygen, vapor is formed.
- Nickel is usually used as the cathode catalyst. It breaks down the ions into water or carbon dioxide.
- Hydrogen is used as the fuel while oxygen is used as the oxidant.
Some points to remember
Many companies are still working on a technique that is being utilized in reducing the amount of platinum used in the production of this current by enhancing the reactivity of the catalyst with carbon silk. Ways of managing the water in the hydrogen cell are also being developed to ensure that the reaction in the cell is not stopped due to either slow or fast evaporation rates.
If the water is evaporated too fast, the membrane that prevents the direct combination of oxygen and hydrogen will be dehydrated and a crack will occur causing a "short circuit". When a too slow evaporation rate is induced reactants might not be able to reach the catalyst since the electrodes will be flooded hence stopping the whole reaction.
To produce the desired amount of energy, two reactions can be combined depending on the anticipated results. If you want to achieve fair voltage you can combine the hydrogen fuel cells in a series circuit, but if you want a higher current the combination of the fuel cells should be in a parallel circuit.
Because hydrogen fuel cells are able to produce power for electric motors or in place of generators they have been successfully used to replace gasoline engines. This has made many people especially those who look for using eco-friendly fuels advocate for its adoption because it doesn't cause pollution. The fact that the byproducts of the chemical reactions involved in producing energy create water and some heat makes it a better option as compared to what is produced in combustion of other fuels. The reactions that give energy to a motion vehicle more than 60% of the energy are also silent unlike those of gasoline reactions.
Although it might be challenging to use these fuel cells in cold places since water is always in the cell, hydrogen fuel cells are more flexible to use and transport as compared to other renewable sources of energy. Automakers have responded by starting producing more green energy cars to replace the gasoline powered engine ones already.