adminFUEL CELLS
Fuel cells are more like batteries; they undergo electrochemical reactions at the anode and cathode to generate electricity. They are not rechargeable like batteries but they need a fuel source to continuously produce or generate electricity.
A fuel cell consist of several components like the battery and they include; the anode, cathode, electrolyte, fuel and oxidant.
The anode is the negative electrode where the fuel is oxidized. The cathode is the positive electrode where the oxygen is reduced. The electrolyte is the material that separates the anode from the cathode and also facilitates the flow of ions. The fuel is the substance that is oxidized at the anode to produce electricity.
Fuel cells work by the reaction of a fuel such as hydrogen with oxygen to produce electricity, heat and water as outputs.
The electrochemical process involves the following; The fuel is oxidized at the anode to produce electrons and protons. The electrons flow through an external circuit to produce electricity. The proton ions flow through the electrolyte to the cathode. The oxygen is then reduced at the cathode to produce water and heat as exhaust waste.
There are several types of fuel cells and they include the following; proton exchange membrane (PEMs) fuel cell, solid oxide (SOFCs)fuel cell, molten carbonate(MCFCs) fuel cell,, phosphorous acid(PAFCs) fuel cell and alkaline(AFCs) fuel cell.
The proton exchange membrane (PEMs) fuel cell uses a proton exchange membrane to separate the anode from the cathode. The solid oxide (SOFCs) fuel cell uses a solid oxide material to separate the anode from the cathode. The molten carbonate (MCFCs) fuel cell uses a molten carbonate material to separate the anode from the cathode. The phosphorous acid (PAFCs) fuel cell uses a phosphorous acid material to separate the anode from the cathode. The alkaline (AFCs) fuel cell uses an alkaline material to separate the anode from the cathode.
The advantages of fuel cells are as follows: Fuel cells produce only water and heat as by products thereby making it green energy compliant. Fuel cells are capable of achieving efficiencies of over 60%. Fuel cells in their application and use are reliable and flexible.
However their main disadvantages are their high investment and operational cost, limited infrastructure and fuel option as well as durability regarding the degradation propensity of the electrolyte.
Fuel cells have found widespread applications in a broad range of industries including; Transportation as prime mover for cars, buses and trucks. Fuel cells have found use in stationary power generation as power plants and other portable power devices. Fuel cells have found widespread use in the space and the military industries to power space and military vehicles and equipment.
The future of fuel cells depend on the following developments and trends; continued research on various fuel cells and fuel cell battery hybrids is expected to result in improved efficiencies, cost reduction, increased infrastructure and new applications for fuel cells.
SOURCES:
- Fuel cells: principles, design and applications by S. Basu.
- Fuel cells and hydrogen: from fundamentals to applied research by Detlef Stolten and Bernd Emonts.
- The fuel cell systems: design, modeling and simulations by S. Kaku.
- Fuel cells: technologies and applications edited by Haijiang Wang and Xiao-zi Yuan.
- Fuel cells: fundamentals and applications edited by Supramaniam Srinvivasan and S. Basu.
