Longer-lasting silicon-air battery breaks 1,000-hour ceiling

JüLICH, Germany, July 27 (UPI) -- For the first time, a silicon-air battery has generated power for more than 1,000 hours.

Silicon-air batteries are smaller, lighter and more energy efficient than lithium-ion batteries. They're also cheaper, more stable and eco-friendly.

An ionic liquid with silicon wafers serves as the fuel source and current medium inside silicon-air batteries. Unlike most batteries, silicon-air batteries are without a cathode. Instead, oxygen flowing into the battery from the atmosphere jump-starts the current.

Unfortunately, silicon-air batteries have only been able to generate a current for short periods of time. Until now, scientists couldn't figure out why.

A new study out of Germany's Jülich Research Center suggests the electrolyte is to blame for the battery's short-circuiting problems. Without consistent contact between electrolyte and anode, the current fizzles out.

Scientists designed a simple pump system that ensures the ion liquid inside the silicon-air battery -- potassium hydroxide dissolved in water -- is periodically refilled.

"If the silicon anode remains in contact with the electrolyte, the battery will continue running," Hermann Tempel, an expert in electrochemistry at Jülich's Institute of Energy and Climate Research, explained in a news release.

As a result of their discovery and quick fix, researchers were able to prolong the battery's current for more than 1,000 hours.

"Until the silicon is fully used up," Tempel said. "The battery can subsequently be recharged by exchanging the anode, in other words mechanically."

Researchers say their solution is only temporary. Their real breakthrough was not lengthening the battery's running time, but learning what exactly was wrong with the technology.

Now, researchers say it's time to go back to work to develop a better electrolyte solution -- one that doesn't deteriorate so quickly.

"We need to stop the battery from self-discharging," said Tempel. "The battery is not yet perfect, but we now know what we have to work on."