Chemistry World Blog

The humble kitchen sponge, whose day-to-day job is to scour dishes, has now been put to work in an energy storage device by scientists in Saudi Arabia.

Husam Alshareef and colleagues from the King Abdullah University of Science and Technology in Thuwal have used a sponge as a platform to support a carbon-based electrode and a transition metal oxide electrode in a supercapacitor, together with an organic electrolyte, a combination that significantly increases the amount of energy that the device can store (energy density) compared to devices using aqueous electrolytes.

Supercapacitors are energy storage devices with a higher power density than batteries, but their low energy density – an obstacle to their use in many potential applications – has led to research into improving it. This can be done in two ways: enhancing the device capacitance by getting the right electrode material and enhancing the working voltage window, which can be done by using an organic electrolyte instead of an aqueous electrolyte.

The team coated a sponge with carbon nanotubes, followed by a layer of MnO₂ (both good electrode materials). They tested the device with organic and aqueous electrolytes and found that it gave a good electrochemical performance with both, but the energy density was tripled with the organic electrolyte. The sponge’s role is to allow electrolytes to flow to the entire electrode surface where the redox reactions take place.

Gives a new meaning to the phrase ‘kitchen chemistry’!

Elinor Hughes