The electrode is made from a hybrid nickel oxide-iron oxide exterior shell and a conductive iron-nickel core.
In a paper published in the Journal of Applied Physics, from AIP Publishing, the researchers report the fabrication technique of the hybrid nanostructure electrode. The scientists also demonstrate the electrode's superior performance compared to existing, non-hybrid supercapacitor electrodes. Since nickel oxide and iron oxide are environmental friendly and cheap materials that are widely available in nature, the novel electrode promises green and low-cost supercapacitors in future.
"This hybrid electrode shows the superior electrochemical performance in terms of high capacitance [the ability to store electrical charge] of nearly 1415 farad per gram, high current density of 2.5 ampere per gram, low resistance and high power density," said Ashutosh K. Singh, the primary researcher at the Department of Condensed Matter Physics and Material Sciences at the S.N. Bose National Centre for Basic Sciences. "It also has a long-term cycling stability, in other words, the electrode could retain nearly 95 percent of initial capacitance after cycling or charging and discharging 3,000 times."
Inspired by previous research on improving conductivity via doping different metal oxide materials, Singh and Kalyan Mandal, another researcher and a professor at the S. N. Bose National Centre for Basic Sciences, mixed nickel oxide and iron oxide as a hybrid material and fabricated the novel core/shell nanostructure electrode.
"By changing the materials and morphologies of the electrode, one can manipulate the performance and quality of the supercapacitors," explained Singh.