Fuel cell | Renewable Energy | Energy Security

Fuel cell (Selenium + Graphene to be used as catalyst instead of very costly platinum)

• Fuel cells are electrochemical devices that convert chemical energy from the reactants directly into electricity and heat.
  • The device consists of an electrolyte layer in contact with a porous anode and cathode on either side.
• In a standard fuel cell, gaseous fuels are fed continuously to the anode (negative electrode), while an oxidant (oxygen from the air) is fed continuously to the cathode (positive electrode). Electrochemical reactions take place at the electrodes to produce an electric current.

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• Advantages of fuel cell systems are:
  • High operating efficiency is not a function of system size.
  • A highly scalable design.
  • Several types of potential fuel sources are available.
  • Zero or near-zero greenhouse emissions.
  • There are no moving parts in the fuel cell stack, which provides reliable, vibration-free operation.
  • Nearly instantaneous recharge capability when compared to batteries.
• Limitations of fuel cell systems are:
  • Cost-effective, mass-produced pure hydrogen storage and delivery technology.
  • Fuel Reformation technology may need to be considered if pure fuel is not used.
  • Fuel cell performance may gradually decrease over time due to catalyst degradation and electrolyte poisoning if pure fuel is not used.
• Comparison of the fuel cell with Battery 
  • The lifetime of a primary battery is limited due to the following:
    • The battery stops producing electricity when the chemical reactants stored in a battery runs out.
    • When a battery is not being used, a very slow electrochemical reaction takes place that limits the lifetime of the battery.
    • The battery life is dependent on the lifetime of the electrode.
    • Advantage: A fuel cell is an energy conversion device where the reactants are supplied. The fuels are stored outside the fuel cell. A fuel cell can supply electrical energy as long as fuel and oxidant are supplied. Also, no “leakage” occurs in a fuel cell, and no corrosion of cell components occurs when the system is not in use.
• Comparison of the fuel cell with Heat Engine
  • A heat engine also converts chemical energy into electric energy, but through intermediate steps. The chemical energy is first converted into thermal energy through combustion. Thermal energy is then converted into mechanical energy by the heat engine; and Finally, the mechanical energy is converted into electric energy by an electric generator.
  • The process also involves moving parts, which implies that they wear over time. Regular maintenance of moving components is required for proper operation of the mechanical components.
  • Advantage: Since fuel cells do not have any moving parts during operation, they are more reliable than heat engines and have less noise. This results in lower maintenance costs, which make them especially advantageous for space and underwater missions.
  • The efficiency of fuel cells is not strongly dependent on operating power. It is their inherently high efficiency that makes fuel cells an excellent option for a broad range of applications, including automobiles, buses, distributed electricity, and portable systems.

* Indian origin scientist invented to generate electricity, harnessing temperature differences to produce renewable electricity at night. http://www.drishtiias.com/images/uploads/1568628496_Image14.jpg