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Alkaline fuel cells operate between ambient temperature and 90 °C with an electrical efficiency higher than fuel cells with acidic electrolyte, such as proton-exchange membrane fuel cells (PEMFC), solid oxide fuel cells, and phosphoric acid fuel cells. Because of the alkaline chemistry, oxygen reduction reaction (ORR) kinetics at the cathode ...
The alkaline fuel cell (AFC) or hydrogen-oxygen fuel cell was designed and first demonstrated publicly by Francis Thomas Bacon in 1959. It was used as a primary source of electrical energy in the Apollo space program. [44] The cell consists of two porous carbon electrodes impregnated with a suitable catalyst such as Pt, Ag, CoO, etc.
The alkaline fuel cell used by NASA in 1960s for Apollo and Space Shuttle program generated electricity at nearly 70% efficiency using aqueous solution of KOH as an electrolyte. In that situation, CO 2 coming in through oxidant air stream and generated as by product from oxidation of methanol, if methanol is the fuel, reacts with electrolyte ...
PEM fuel cells were used in the NASA Gemini series of spacecraft, but they were replaced by Alkaline fuel cells in the Apollo program and in the Space Shuttle. General Electric continued working on PEM cells and in the mid-1970s developed PEM water electrolysis technology for undersea life support, leading to the US Navy Oxygen Generating Plant.
Electro- chemical reaction Diagram of PEM MEA. A membrane electrode assembly (MEA) is an assembled stack of proton-exchange membranes (PEM) or alkali anion exchange membrane (AAEM), catalyst and flat plate electrode used in fuel cells and electrolyzers. [1][2]
Francis Thomas Bacon OBE FREng FRS [1] (21 December 1904 – 24 May 1992) was an English engineer who in 1932 developed the first practical hydrogen–oxygen fuel cell. It is used to generate power for space capsules and satellites. Bacon was awarded an OBE by Queen Elizabeth II in the 1967 New Year Honours. In 1976, Bacon was a founder fellow ...
The LHV must be used for alkaline electrolysers as the process within these electrolysers requires water in liquid form and uses alkalinity to facilitate the breaking of the bond holding the hydrogen and oxygen atoms together. The lower heat value must also be used for fuel cells, as steam is the output rather than input.
Direct borohydride fuel cell. Direct borohydride fuel cells (DBFCs) are a subcategory of alkaline fuel cells which are directly fed by sodium borohydride or potassium borohydride as a fuel and either air/oxygen [1] or hydrogen peroxide [2] as the oxidant. DBFCs are relatively new types of fuel cells which are currently in the developmental ...