Molten carbonate fuel cells disadvantages

Several types of fuel cells have been developed and are classified according to the electrolytes used alkaline fuel cells, molten carbonate fuel cells, phosphoric acid fuel cells (PAFCs), PEMFCs, and solid oxide fuel cells (SOFCs). As shown in Figure 1.3, the optimum operation temperatures of these fuel cells are different, and each type has different advantages and disadvantages. 

Many different types of fuel-cell membranes are currently in use in, e.g., solid-oxide fuel cells (SOFCs), molten-carbonate fuel cells (MCFCs), alkaline fuel eells (AFCs), phosphoric-acid fuel cells (PAFCs), and polymer-electrolyte membrane fuel cells (PEMFCs). One of the most widely used polymers in PEMFCs is Nalion, which is basically a fluorinated teflon-like hydrophobic polymer backbone with sulfonated hydrophilic side chains." Nafion and related sulfonic-add based polymers have the disadvantage that the polymer-conductivity is based on the presence of water and, thus, the operating temperature is limited to a temperature range of 80-100 °C. This constraint makes the water (and temperature) management of the fuel cell critical for its performance. Many computational studies and reviews have recently been pubhshed," and new types of polymers are proposed at any time, e.g. sulfonated aromatic polyarylenes," to meet these drawbacks. 

Use chemical equations to explain how the molten carbonate fuel cell (MCFC) works. What are its advantages and its disadvantages ... 

The molten carbonate fuel cell (MCFC) operates at high temperature, which is about 600-700 °C. It consists of two porous conductive electrodes in contact with an electrolyte of molten carbonate. This type of cell allows the internal reform. The main advantage of the MCFC is its high efficiency (50-60%) without external reformer and metal catalyst, due to the high operating temperature (Farooque Maru, 2001). This cell is intolerant to sulfur and its launching is slow, these are its main disadvantages. 

Molten carbonates, however, do have disadvantages. The fuel cell takes a considerable amount of time to reach its high operating temperature, so it is unsuitable for powering a car or truck. The liquid carbonate electrolyte is very corrosive, so there is some question about the lifetime these fuel cells will be able to achieve. They are also very bulky The 250 kW units are the size of a railroad car and weigh about forty tons. 

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