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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.
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Zincate diffusivity in alkaline electrolyte determined as function of potassium hydroxide concentration and temperature
Electrochemical oxidation of zinc, thermal decomposition of silver oxide, and solubility determinations of silver oxides in potassium hydroxides
Electrochemical oxidation of zinc, thermogravimetric investigation of silver oxide, and rate of solution of silver oxide in potassium hydroxide
Electrochemical oxidation of zinc and cadmium in potassium hydroxide - thermal decomposition, and deposition of silver oxide on zinc anodes
Charge and discharge rates of potassium amalgam electrodes in alkaline solution and silver diffusion in potassium hydroxide
Gold alloys electrocatalytic activity in cathodic reduction of oxygen in potassium hydroxide
Partial pressure of carbon dioxide within a space suit is maintained at safe levels by regenerating carbon dioxide with potassium hydroxide solution on board spacecraft or by portable units.
The PC8B-4 fuel cell electrical power supply is an electrical powerplant designed to convert the chemical reaction of hydrogen and oxygen into electrical energy. It utilizes catalyzed electrodes with a potassium hydroxide electrolyte. The powerplant and test stand control unit are described together with a specifications summary. Separate sections deal with: performance, reactants supply and control, heat removal, water removal instrumentation, operation, and safety considerations.
Three different terminals were designed for usage in a 40 ampere/hour silver zinc battery which has a 45 percent KOH by weight electrolyte in a plastic battery case. Life tests, including thermal cycling, electrical charge and discharge for up to three years duration, were conducted on these three different terminal designs. Tests for creep rate and tensile strength were conducted on the polyphenylene oxide (PPO) plastic battery cases. Some cases were unused and others containing KOH electrolyte were placed on life tests. The design and testing of nonleaking battery terminals for use with a potassium hydroxide (KOH) electrolyte in a plastic case are discussed.
A fuel cell technology program was established to advance the state-of-the-art of hydrogen-oxygen fuel cells using low temperature, potassium hydroxide electrolyte technology as the base. Program tasks are described consisting of baseline cell design and stack testing, hydrogen pump design and testing, and DM-2 powerplant testing and technology extension efforts. A baseline cell configuration capable of a minimum of 2000 hours of life was defined. A 6-cell prototype stack, incorporating most of the scheme cell features, was tested for a total of 10,497 hours. A 6-cell stack incorporating all of the design features was tested. The DM-2 powerplant with a 34 cell stack, an accessory section packaged in the basic configuration anticipated for the space shuttle powerplant and a powerplant control unit, was defined, assembled, and tested. Cells were used in the stack and a drag-type hydrogen pump was installed in the accessory section. A test program was established, in conjunction with NASA/JSC, based on space shuttle orbiter mission. A 2000-hour minimum endurance test and a 5000-hour goal were set and the test started on August 8, 1972. The 2000-hour milestone was completed on November 3, 1972. On 13 March 1973, at the end of the thirty-first simulated seven-day mission and 5072 load hours, the test was concluded, all goals having been met. At this time, the DM-2 was in excellent condition and capable of additional endurance.
Transient mass transfer at the rotating disk has been investigated theoretically and experimentally for cathodic reduction of ferricyanide in the redox system ferricyanide-ferrocyanide with potassium hydroxide supporting electrolyte. It has been shown that overpotential-time predictions for the rotating disk are fitted very well for decay (current interruption) but poorly for build-up following switching on of constant current. As an explanation for this behavior, attention is directed to the inadequacy of the assumption that a radially independent concentration profile exists at the disk surface just at the start of galvanostatic current passage.
Material can be regenerated at least 20 times by heating at 250 C. Sorbent is compatible with environment of high humidity; up to 20% by weight of carbon dioxide can be absorbed. Material is prepared from silver carbonate, potassium hydroxide or carbonate, and sodium silicate.
Standard production procedures for manufacturing silver zinc batteries are evaluated and modified to reduce oxygen generation during open circuit stand and discharge. Production predictions of several variable combinations using analysis models are listed for minimum gassing, with emphasis on the concentration of potassium hydroxide in plate formation. A recommendation for work optimizing the variables involved in plate processing is included.
Cells use potassium hydroxide electrolyte and are hermetically sealed in stainless steel casings. Each cell provides 1.56 volts and has a minimum operating life of 17,000 hours and a maximum of approximately 48,000 hours.
Silicon solar cells with macroscopic V-shaped grooves and microscopically texturized surfaces were made by preferential etching techniques. Various conditions for potassium hydroxide and hydrazine hydrate etching were investigated. Optical reflection losses from these surface were reduced. The reduced reflection occurred at all wavelengths and resulted in improved short circuit current and spectral response. Improved collection efficiency is also expected from this structure due to generation of carriers closer to the cell junction. Microscopic point measurements of collected current using a scanning electron microscope showed that current collected at the peaks of the texturized surface were only 80 percent of those collected in the valleys.
The concentration and distribution of aqueous potassium hydroxide (KOH) electrolyte in a sealed nickel cadmium cell is considered. The reactions at both electrodes during charge and discharge involve the production or utilization of hydroxyl ion (OH) or water (H2O) which directly affects concentration. Changes in electrolyte concentration relative to the individual electrode reactions is discussed. Quantitative values are provided for the changes in concentration for 6, 12, and 20 ah cells with accepted quantities of precharge and accepted initial quantity of 31% aqueous KOH. Consideration is given to a more correct equation which includes net changes in hydroxyl concentration in addition to water. Also, expected concentrations of electrolyte in cells in the fully charged, 75% charged, 50% charged, 25% charged and discharged condition are calculated. The expected concentration changes for cells in the accelerated tests are also tabulated and compared with measured values. All calculations are made on the assumption that there are no side reactions. Various properties which depend on KOH concentration are listed. The variables include O2, H2, and Cd(OH)2 solubilities in addition to viscosity and conductivity.
Silicon solar cells with macroscopic V-shaped grooves and microscopically texturized surfaces have been made by preferential etching techniques. Various conditions for potassium hydroxide and hydrazine hydrate etching were investigated. Optical reflection losses from these surface were reduced. The reduced reflection occurred at all wavelengths and resulted in improved short circuit current and spectral response. Improved collection efficiency is also expected from this structure due to generation of carriers closer to the cell junction. Microscopic point measurements of collected current using a scanning electron microscope showed that current collected at the peaks of the texturized surface were only 80% of those collected in the valleys.
Potassium hydroxide in ethyl alcohol solution can strip away coatings, adhesives, and encapsulants without damaging substrates.