What does DEFC mean in UNCLASSIFIED

Direct ethanol fuel cells (DEFC) are electrochemical cells that generate electricity from the direct oxidation of ethanol. They are an attractive alternative to traditional power sources because they are clean, highly efficient, and renewable.

Direct ethanol fuel cells typically use a liquid solution of an electrolyte (i.e. salt or acid) and ethanol as the reactant in their reaction. The electrolyte facilitates the transfer of ions between the two electrodes of the cell, which causes electrons to flow between them and generate an electric current.

One major advantage of a DEFC system is its high efficiency - it usually produces more energy than other types of fuel cells as it requires less energy to produce electricity from its reactants. Additionally, DEFC systems also have low emissions and no hazardous waste, making them environmentally friendly.

Yes - direct ethanol fuel cells can be used in various types of vehicles such as cars, buses and boats. They provide an efficient alternative to traditional combustion engines and offer higher performance while also reducing emissions significantly.

One potential limitation with DEFC systems is that they require larger amounts of expensive materials for their construction than other types of fuel cells, due to their relatively large size and complexity. Additionally, their reactants can also be costly if purchased in large quantities for industrial-level applications.

The lifespan of a direct ethanol fuel cell depends on several factors such as operating conditions and maintenance but generally has good longevity - with proper care they can operate without issue for several years before needing servicing or replacement parts/cells.

Yes - like any other type of energy source, direct ethanol fuel cells require periodic refueling in order to maintain their performance level over time. This is usually done by refilling the liquid solution containing the electrolyte and reactants into the cell's tank or reservoir at regular intervals according to manufacturer specifications.

Yes - most commercial DEFC systems are designed with safety features such as temperature sensors and pressure release valves that ensure optimal operation at all times while preventing any potential accidents or malfunctions from occurring during normal operation. It is also important to follow proper safety protocols during installation, maintenance and refueling operations for further risk reduction purposes. 

The cost varies depending on the size and type of DEFC system being purchased but generally ranges from several hundred dollars up to tens of thousands for larger-scale installations requiring multiple units linked together in order scale up output power capacity accordingly.