Bote Zhao1 Dongchang Chen1 Meilin Liu1

1, Georgia Institute of Technology, Atlanta, Georgia, United States

Hybrid supercapacitors, composed of a capacitive electrode and a battery-type faradaic electrode, have demonstrated significantly higher energy density than conventional carbon-based electrical double-layer capacitors (EDLCs), due largely to the higher capacity of the battery-type electrode and the broader voltage window of the electrode pair. As a promising battery-type electrode for hybrid supercapacitor, nickel compounds-based electrodes could theoretically deliver high specific capacity and rate capability in alkaline aqueous electrolyte. However, nickel compounds-based electrodes usually suffer from an irreversible phase transition, large volume variation, and low electronic conductivity, resulting in poor durability and limited rate capability. In this presentation, we will highlight our recent progress in investigations into the charge storage mechanism of nickel compounds-based electrodes in order to develop knowledge-based materials design strategies, including in-operando resonance Raman spectroscopic measurements, density functional theory (DFT)-based calculations, and controlled synthesis of advanced nanostructures. Perspectives for a new generation of hybrid supercapacitors for various applications will be discussed as well.