Professor Jae-Hyung Jang's research team develops high performance energy storage device with reduced oxidized graphene
□ Professor Jae-Hyung Jang of the School of Electrical Engineering and Computer Science at the Gwangju Institute of Science and Technology (GIST, President Seung Hyeon Moon) said, "We succeeded in the development of high performance hybrid super capacitor * technology that has energy storage density * 2 ~ 3 times higher than conventional graphene electrode and has 15 times higher power density * than lithium ion battery."
* Energy storage density: the amount of energy stored per unit volume of the energy storage system
* Power density: the electric energy per unit time divided by the unit weight or unit volume
* Hybrid supercapacitor: a supercapacitor composed of capacitor electrode and battery electrode
□ The hybrid supercapacitor electrode * using a graphene scroll * developed by the team has a volumetric energy density of 49.66 Wh/L and has a volume energy density 2 ~ 3 times higher than conventional graphene electrodes. The power density of this electrode is 7,614 W/L, which is 15 times higher than that of the 500 W/L of lithium-ion batteries, and can be charged and discharged more than 10,000 times.
* Electrode: conductive medium that makes interface contact electrolyte and electrode
□ The researchers explained that excellent energy densities and power densities without losing high-speed charge / discharge functions are due to the nanoscale * scrolls (nanoscrolls) that are formed by rolling oxidized graphene *. If a single layer of reduced graphene is simply stacked, the area of the ion-graphene is not approached, and the performance of the cell deteriorates due to the reduced area of adsorbed ions. By contrast, when the reduced graphene is rolled into a rolled shape, the tip and corners of the nanoscroller become open, maximizing the available surface area and thus increasing the area of reaction with ions. In addition, the pores (holes) are uniformly arranged so that the ions move smoothly to the inside, and the pore size of 3 nanometers (nm) is suitable for migration and diffusion of ions, thus allowing the optimum electrochemical performance.
* Reduced oxidation graphene: a carbon material obtained by chemically reducing oxidized graphene through a reducing agent
* Nanoscale: structures with a length of 1-100 nm that are applicable to nanotechnology
□ Professor Jae-Hyung Jang said, "This research has developed a hybrid supercapacitor with high charging density and high energy density even without additional additives or complicated processes. It is expected to be applicable to energy storage devices required for electric vehicles, portable electronic devices, and the like."
□ This research was supported by a GIST Research Institute (GRI), the National Research Foundation of Korea (NRF) funded by the Ministry of Science, ICT and Future Planning, and the Technology Innovation Program funded by the Ministry of Trade, Industry & Energy. The paper entitled "High Volumetric Energy Density Hybrid Supercapacitors Based on Reduced Graphene Oxide Scrolls" was authored by Janardhanan R. Rani, Ranjith Thangavel, Se-I Oh, Jeong Min Woo, Nayan Chandra Das, So-Yeon Kim, Yun-Sung Lee, and Jae-Hyung Jang and was published in Applied Materials & Interfaces on June 14, 2017.
