- Metal hydride fuel cell
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Metal hydride fuel cells are a subclass of alkaline fuel cells that are currently in the research and development phase. A notable feature is their ability to chemically bond and store hydrogen within the cell. This feature is shared with direct borohydride fuel cells, although the two differ in that MHFCs are refueled with pure hydrogen. Though the absorption characteristics of metal hydrides (around 2%) is far lower than sodium-borohydrides and other "light" metal hydrides (around 10,8%)[1], prototypes have been claimed to demonstrate a number of interesting characteristics:
- Ability to be recharged with electrical energy (similar to NiMH batteries);
- Low operating temperatures (down to -20°C);
- Fast kinetics;
- Extended shelf life;
- Fast "cold start" properties;
- Ability to operate for limited periods of time with no external hydrogen source, enabling "hot swapping" of fuel canisters.
Metal hydride fuel cells are currently being researched by ECD Ovonics, as well as by the Japanese National Institute of Advanced Industrial Science and Technology (AIST). Though similar, the two MHFC concepts use different catalysts.[2][3] Thus far, neither research project has produced a demonstratable model outside of a laboratory - only publications and patents - and significant efficiency hurdles have yet to be overcome. The Ovonics and AIST metal hydride fuel cells claim current densities of only 250mA/cm2 and 20mA/cm2, respectively, versus typical PEMFC performance at 1A/cm2.
Bibliography
- Appleby, John; C. Wang, F. Little (2003). "High Power Alkaline Fuel Cell with Intrinsic Energy Storage". 204th Meeting of the Electrochemical Society. The Electrochemical Society, Inc.
- Wang, X.H.; et al. (1999). "Electrochemical properties of Ml(NiCoMnCu)5 used as an alkaline fuel cell anode". Journal of Alloys and Compounds 293-295: 833–837. doi:10.1016/S0925-8388(99)00367-9.
- Lee, S-M.; J.-H. Kim, H.-H. Lee, P S. Lee and J.-Y. Lee (2002). "The Characterization of an Alkaline Fuel Cell that Uses Hydrogen Storage Alloys". Journal of the Electrochemical Society 149 (5): A603–A606. doi:10.1149/1.1467365.
- Tanaka, H.; N. Kaneki, H. Hara, K. Shimada and T. Takeuchi (April 1986). "La-Ni System Porous Anode in an Alkaline Fuel Cell". Canadian Journal of Chemical Engineering 64 (2): 267–271. doi:10.1002/cjce.5450640216.
See also
External links
Fuel cells Types Alkaline fuel cell · Blue energy · Direct borohydride fuel cell · Direct carbon fuel cell · Direct-ethanol fuel cell · Direct methanol fuel cell · Electro-galvanic fuel cell · Enzymatic biofuel cell · Formic acid fuel cell · Flow battery · Molten carbonate fuel cell · Microbial fuel cell · Metal hydride fuel cell · Phosphoric acid fuel cell · Protonic ceramic fuel cell · Photoelectrochemical cell · Proton exchange membrane fuel cell · Regenerative fuel cell · Reformed methanol fuel cell · Solid oxide electrolyser cell · Solid oxide fuel cell · Unitized regenerative fuel cell · Zinc-air batteryHydrogen Categories:- Fuel cells
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