Understatement

This story, about a possible revitalization of Nickel-Hydrogen battery technology, makes a crucial oversight that should be pointed out.

Evidently some startup has reinvented an old technology, Nickel-Hydrogen batteries, to be more mechanically robust, and have between 1/2 to 2/3 the energy density of Lithium Ion batteries. I'm not sure if this claim is actually true, or if their NiH2 batteries are commercially viable, but if they are, this could be fairly interesting. Unlike Lithium Ion batteries, NiH2 batteries can be charged and discharged tens of thousands of times without becoming significantly degraded.

The article points out that 1/2 to 2/3 the energy density would translate to reduced range for electric vehicles, such as the Chevy Volt - instead of 40 electric miles, you would only have 20 to 30. But the author forgot that fully 45% of the Chevy Volt's battery capacity is not used! Because Lithium batteries can only be cycled fully a few hundred times before losing much of their capacity, the Volt carries around twice as much battery as it really needs. This extra capacity "babies" the Volt's battery, so that instead of charging and discharging from 100%-0%-100%, the Volt goes from 85%-30%-85%, which greatly increases the lifetime of the battery. So, a chemistry with effectively unlimited charge cycle capacity would allow downsizing the battery significantly, which could cancel out the reduced energy density.

There may be other reasons why the NiH2 batteries won't end up working for electric cars, but the energy density problem, at least for Extended-range electric or plugin-hybrid vehicles, seems not to be an issue. Too bad the authors of this article didn't think that through.