The process is repeated to build up alternating layers of positive and negative ions on top of each other.

ECONOMIST: MONITOR

By using atmospheric air and negative ions, a natural cleansing agent, it fights dirt and bacteria with nature's own weapon, he said.

CNN: Ioning your way to cleaner clothes

National University of Singapore industrial design students Gabriel Tan and Wendy Chua's prototype uses negative ions, compressed air and anti-bacterial deodorants to clean clothes.

CNN: Ioning your way to cleaner clothes

In an ultracapacitor, positively charged ions gather on the surface of the negatively charged electrode and negative ions on the surface of the positive electrode.

ECONOMIST: Electricity storage