Could the six-hour runtime of a netbook go to 36 hours in the future? It sounds possible based on recent ionic battery projects. Battery technologies simply haven’t undergone a major change in years, so most of our runtime gains have come through more power efficient hardware. But if I’m reading the news right, ionic liquid powered batteries might be the breakthrough to change that. According to Cody Friesen, a professor of materials science at Arizona State and founder of Fluidic Energy:
“[A] metal-air battery using an ionic liquid as its electrolyte not only functions significantly longer–because drying out is no longer a problem–but it also gets a big boost in energy density. “These liquids have electrochemical stability windows of up to five volts, so it allows you to go to much more energy-dense metals than zinc.” He says his research team will target energy densities of at least 900 watt-hours per kilogram and up to 1,600 watt-hours per kilogram in the DOE-funded project.”
As I see it, this technology is really geared for electric vehicles with large batteries. But I could envision this technology making its way down to notebook batteries. And if it did, you could “cram” more energy in a battery without increasing the size and weight.
Some quick math using the project’s median target shows why I’m hoping this comes to pass. If a 1 kilogram / 35.5 ounce ionic battery can hold 1250 Whr of juice, that’s about 125 Whr per 0.1 kilograms / 3.5 ounces. That works out to an energy density of 35.7 Whr per ounce of battery weight. The battery of my Toshiba NB205 battery weighs 11 ounces, so an ionic battery of similar weight could offer 392 Whr as opposed to the 63 Whr my current battery offers. I’m all for more efficient electric cars, but the ability to run my netbook for nearly a week of work time is pretty appealing too.