Aluminum-Based Anodes for Underwater Fuel Cells - A Phase Report.
Research and development rept. Jul-Dec 71,
DAVID W TAYLOR NAVAL SHIP RESEARCH AND DEVELOPMENT CENTER ANNAPOLIS MD PROPULSION AND AUXILIARY SYSTEMS DEPT
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The anodic properties of various aluminum alloys were studied potentiostatically with measurement of hydrogen evolution and potential. Also, an aluminum-oxygen fuel cell was examined for its polarization behavior. Hydrogen evolution at the aluminum anode represents a serious loss of efficiency, since the metal is consumed without delivery of power to the external circuit. The lowest rate of anodic hydrogen evolution at any given potential was measured on high-purity aluminum, since impurities tend to increase the rate of hydrogen evolution. Temperature studies on aluminum fuel cells indicate that power efficiency drops severely over 50C. At 50C, power efficiencies exceeding 50 at a power density of 100 Asq ft 108 mAsq cm were obtained. At 175 and 225 Asq ft 188 and 242 mAsq cm, the power efficiency dropped to 40 and 30, respectively. Freon may be circulated through the fuel cell during periods of reduced or no load to diminish the hydrogen self-discharge with no adverse effects after restarting. The aluminum-seawater system exhibits high-energy density, but it is rather inactive. Aluminum-lithium alloys coupled with seawater appear to be more desirable systems than those of pure aluminum because of their higher reactivity power density, higher specific energy, and self-activating properties no caustic inventory required. Author
- Electric Power Production and Distribution