*1.6.2. DMFC*

"DMFC" uses polymer membrane as an electrolyte such as the polymer electrolyte membrane fuel cells (PEMFC). The distinction lies in the anode catalyst that draws hydrogen from the liquid methanol[11], eliminating the need for reformer. Therefore, pure methanol can be used as fuel.

#### *1.6.3. MCFC*

"MCFC" uses molten carbonate salt mixture suspended in a porous, chemically inert ceramic lithium aluminum oxide (LiAlO2) matrix as the electrolyte. In molten carbonate fuel cells, negative ions travel through the electrolyte to generate water and electrons[4]. They operate at extremely high temperatures of about 650°C and beyond. MCFCs offer significant reduction in cost by using non-precious metals as catalysts at the electrodes. The efficiency level is up to Electrodeposition of Functional Coatings on Bipolar Plates for Fuel Cell Applications – A Review http://dx.doi.org/10.5772/62169 237

**Figure 5.** Showing components of direct methanol fuel cell (www.daviddarling.info)

which chemical reactions take place in the cell. They are also very efficient in space applications

The major setback of this fuel cell is carbon dioxide poisoning of the electrolyte. Even little concentration of carbon dioxide in air can adversely affect its operation, making it necessary to purify the hydrogen and oxygen before use. This affects the cell's lifetime and incurs additional cost. AFC stacks have at least 8000 average operating hours and to make it eco‐ nomically viable for large-scale utility operations, operating times exceeding 40,000 hours are

needed. This is possibly the most significant hindrance to its commercialization.

**Figure 4.** Showing components of alkaline fuel cell (www.fuelcellmarkets.com)

"DMFC" uses polymer membrane as an electrolyte such as the polymer electrolyte membrane fuel cells (PEMFC). The distinction lies in the anode catalyst that draws hydrogen from the liquid methanol[11], eliminating the need for reformer. Therefore, pure methanol can be used

"MCFC" uses molten carbonate salt mixture suspended in a porous, chemically inert ceramic lithium aluminum oxide (LiAlO2) matrix as the electrolyte. In molten carbonate fuel cells, negative ions travel through the electrolyte to generate water and electrons[4]. They operate at extremely high temperatures of about 650°C and beyond. MCFCs offer significant reduction in cost by using non-precious metals as catalysts at the electrodes. The efficiency level is up to

*1.6.2. DMFC*

as fuel.

*1.6.3. MCFC*

with efficiencies up to 60%[10].

236 Electrodeposition of Composite Materials

60% which is considerably higher than 35–50% efficiencies of a phosphoric acid fuel cell. Overall, fuel efficiencies mount up to about 85% when the waste heat is captured and used. As a result of the elevated temperature at which it works, the fuels are converted to hydrogen by a process known as internal reforming within the fuel cell. This also makes it economical.

**Figure 6.** Showing components of molten carbon fuel cell (www.fuelcellmarkets.com)
