Energy Density Improvements in Lightweight Lithium-Air Batteries

Via ecogeek.org, 27-07-2011

MIT scientists have made new discoveries that could significantly increase the energy density of batteries several times beyond the current level of lithium-ion batteries. The advances are in lithium-air storage, which uses a porous carbon electrode in place of a heavy solid electrode in the battery. Oxygen from the air reacts with the lithium metal in the battery to store and discharge energy. The very open structure makes it possible to obtain such high levels of performance.

One of the biggest issues in battery development is the weight of the batteries. Whether for portable electronic devices or for hybrid and electric vehicles, the weight of the batteries is a factor that must be considered. Replacing the solid electrode with the lightweight carbon matrix has led to some of the highest levels of energy stored per pound of battery.

New methods of producing the carbon matrix for the battery creates a “carpet-like” material that is more than 90 percent open, which makes for a very lightweight battery. “These carpet-like arrays provide a highly conductive, low-density scaffold for energy storage,” according to one of the researchers.

As an additional benefit, the researchers have found that the very open and regular nature of the battery allows scrutiny of its internal workings with a scanning electron microscope. Not only does this allow more research on the particulars of this battery, but it may also help with general research and understanding of why batteries have limited numbers of charge-discharge cycles before they cease being useful.

via: MIT press release