A KAIST research team has developed a graphene-based hybrid storage device with power density 100 times faster than conventional batteries, allowing it to be charged within a few seconds. The team states that it could be suitable for small portable electronic devices.

KAIST team develops a fast and powerful graphene-based aqueous hybrid capacitor that may lead to a new type of energy storage system imagePorous metal oxide nanoparticles formed on graphene in the aqueous hybrid capacitor. (Image: KAIST)

The researchers developed an aqueous hybrid capacitor (AHC) that boasts high energy density, high power, and excellent cycle stability by synthesizing two types of porous metal oxide nanoclusters on graphene to create positive and negative electrodes for AHCs.

The porous metal oxide nanoparticles are composed of nanoclusters as small as two to three nanometers and have mesopores that are smaller than five nanometers. In these porous structures, ions can be rapidly transferred to the material surfaces and a large number of ions can be stored inside the metal oxide particles very quickly due to their small particle size and large surface area.

The team applied porous manganese oxide on graphene for positive electrodes and porous iron oxide on graphene for negative electrodes to design an aqueous hybrid capacitor that can operate at an extended voltage range of 2V.

Professor Jeung Ku Kang, who led the research, said, “This newly developed AHC with high capacity and power density driven from porous metal oxide electrodes will contribute to commercializing a new type of energy storage system. This technology allows ultra-fast charging within several seconds, making it suitable as a power source for mobile devices or electric vehicles where solar energy is directly stored as electricity.”