Alkaline fuel cells Apollo

Alkaline fuel cells (AFCs). The electrolyte is 40 to 70% KOH, the working temperatures are 60 to 240°C. Such systems were used in the spacecraft of the Apollo program and in the U.S. space shuttle. 

AFC Alkaline fuel cell 30-50% KOH OH- (hydroxide) 60-90 7kW (Apollo) 37-s42% Immediate Space travel, road vehicles, submarines... 

The Alkaline Fuel Cell (AFC) was one of the first modern fuel cells to be developed, beginning in 1960. The application at that time was to provide on-board electric power for the Apollo space vehicle. Desirable attributes of the AFC include its excellent performance on hydrogen (H2) and oxygen (O2) compared to other candidate fuel cells due to its active O2 electrode kinetics and its flexibility to use a wide range of electrocatalysts, an attribute which provides development flexibility. 

In alkaline fuel cells (AFCs), the electrolyte is 34-46% KOH, immobilized on a porous support, and the operating temperature is 60-120 °C. Because the environment is alkaline, Raney nickel (a finely divided form of nickel) can be used in place of expensive platinum. However, the alkali will be neutralized by any CO2 in the hydrogen fuel, so AFCs are not suitable for operation with reformed hydrocarbons but can be fueled with alcohols or hydrazine. AFCs were used successfully on the Apollo space missions. 

Alkaline Fuel Cell (AFC). This cell follows directly from the one that Bacon and Watson produced at Cambridge in the 1950s and is the basis of cells developed for NASA (by International Fuel Cells and predecessor companies (United Technologies Power Systems Divisions, Pratt and Whitney Aircraft) since the Apollo moon program, where pure H2 fuel is available. 

Combining the essences of previous researchers work, a new alkaline fuel cell that could operate at 200°C was successfully designed in the 1940s [8, 9], The fuel cell provided a current density of 1 A/cm2 at a cell voltage of 0.8 V, a significant jump in progress. Based on this prototype, Bacon in 1952 successfully developed a 5 kW AFC power plant, which resulted in the construction of alkaline fuel cell power plants by Pratt Whitney, who designed and developed the fuel cell system as part of the power supply system for the Apollo aircraft. 

Alkaline fuel cells (AFCs) were the first type of fuel cell to be widely used in space exploration applications-for example, in NASA s Apollo and space shuttle flights. Figure 1.8 shows a schematic of an AFC stmcture. AFCs use H2 and 02 as fuel and oxidant, respectively. The electrolyte is a concentrated KOH solution absorbed into an asbestos matrix. The temperature for AFCs ranges from 100-250°C and the efficiency can be > 60%. OH ions are transported through the electrolyte from cathode to anode. The reactions are as follows ... 

Alkaline fuel cell (AFC) was used for Apollo and Space Shuttle program. Alkaline fuel cell employs liquid alkaline, e.g., KOH, as an electrolyte so that fuel, as well as air or oxygen, should be free of CO2 because the strong alkaline electrolyte reacts with CO2 to form carbonates, which reduces the ionic conductivity. Electrodes, e.g., Ni, Ag, and metal oxides, are relatively inexpensive compared to that of other fuel cells. 

Figure 6.2 (a) Assembly of alkaline fuel-cell modules for Project Apollo missions ... 

Already in the 1960s fuel cell systems have been used in aerospace, especially as the need for electric power on board was rising and batteries could not cope with those requirements. That is why alkaline fuel cells have been used in the Gemini and Apollo program or latest in the space shuttle. 

Alkaline fuel cells (AFC) using aqueous KOH as electrolyte were the first type of fuel cells with practical applications at the beginning of the last century [9] but the formation of carbonate in the liquid electrolyte due to the CO2 contamination in the oxidant gas stream has limited its application to systems miming with pure oxygen, such as the fuel cells used by the NASA in the I960 Apollo space program, and currently used in the shuttle missions [10]. 

Electrochemical Impedance Studies of AFC Cathodes. A review of the state of the art of alkaline fuel cell is given by McLean et al. [2002]. The electrolyte in AFC is a concentrated KOH solution, 25-50 wt% when operated at 120°C or below and in older AFC systems, operated at 250°C a 85 w/o KOH solution was used. The AFC was first fuel cell developed to technical maturity, based on the fundamental research of Bacon [1952] and has been employed extensively in the NASA space programs Apollo program (1960-1965) and space shuttle program (since 1981). 

The alkaline fuel cell (AFC), also known as the Bacon fuel cell after its British inventor, is one of the most developed fuel-cell technologies and is the cell that flew Man to the Moon. NASA has used alkahne fuel cells since the mid-1960s, in Apollo-series missions and on the Space Shuttle. [2]... 

The electrolyte can be an aqueous solution, alkaline or acid. It was alkaline fuel cells that generated the necessary electricity on Apollo 11, the first manned spacecraft to the moon. In modern fuel cells a membrane may act as a solid electrolyte. A polymer PEMFC (Proton Exchange Membrane Fuel Cell) is often used. 

Thus, in 1898, Wilhelm Ostwald proclaimed that the energy supply of the future would be tied to electrochemistry and would be smoke-free. Subsequent work on fuel cells was hardly successful enough—largely, from what we know now, because of problems with materials—and the inevitable period of calm that followed did not end until 1959, when Francis Bacon demonstrated his stack of alkaline fuel cells. His patents were basic for the Pratt Whitney fuel cells in Apollo space flight. This situation led to the first real fuel cell boom. (Remember at this point to appreciate Bacon s effort that he begun work on his device in 1932.)... 

However, the problem of water management in the electrolyte, which we consider in some detail in Section 4.4 below, was judged too difficult to manage reliably, and for the Apollo vehicles, NASA selected the rival alkaline fuel cell (Warshay, 1990). General Electric also chose not to pursue commercial development of the PEMFC, probably because the costs were seen as higher than other fuel cells, such as the phosphoric acid fuel cell then being developed. At that time catalyst technology was such that 28 mg of... 

This mobile electrolyte system was used by Bacon in his historic alkaline fuel cells of the 1950s and in the Apollo mission fuel cells. It is almost universally used in terrestrial systems, but the Shuttle Orbiter vehicles use a static electrolyte, as described in the next section. 

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