Friday, July 25, 2008

New Battery Type Has More Energy Density

This new type of battery does not burn fuel like a fuel cell, and is not a reversible reaction like rechargeable batteries. But it does have comparable energy density to gasoline--a first for an electric battery type.
As in a zinc air cell, the vanadium boride cell reacts oxygen brought in via the cathode with the anode to produce electricity. And also as in a zinc-air cell, the reaction is irreversible; spent anodes need to be replaced in a “refueling” operation and chemically regenerated. (Earlier post.) The vanadium boride cells combine a conventional air cathode with a zirconia-stabilized vanadium boride anode.

...For regeneration of the anodes, Licht and his team proposed a solar photochemical pathway based on Mg reduction of the fuel cell discharge products.

The large volumetric capacity of the fuel cell, and the pathway for a renewable (solar) energy recharge, are positive attributes of this novel vanadium boride air cell. Systems aspects will continue to be analyzed and optimized. Liquid (higher temperature, solar driven), rather than solid, Mg, should facilitate the recharge formation of VB2...The discharge studies indicate that sub micron particle size VB2, as available following high energy ball milling, can further improve anodic kinetics and coulombic efficiency.
—Licht 2008 _GCC
Achieving this level of energy density makes it worthwhile to explore efficient methods of recharging the cell. If the researchers can achieve a type of solar re-charging system, the new cell might form the basis of new electric vehicle fleets with ready access to a maintenance/recharge facility--taxis, buses, delivery vans, etc. Eventually it may be possible to achieve affordable and reliable home recharge for this type of cell.

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