C 60 /Na 4 FeO 3 /Li 3 V 2 (PO 4 ) 3 /soft carbon quaternary hybrid superstructure for high-performance battery-supercapacitor hybrid devices

To develop battery-supercapacitor hybrid devices with high energy and power densities, we propose a rational design of a quaternary hybrid superstructure by using a high-energy biotemplate. This new superstructure is composed of stable fullerene C 60 nanocages, electroactive Na 4 FeO 3 , high-energy Li 3 V 2 (PO 4 ) 3 and soft carbon as well as tubular ordered mesoporous channels. This design takes advantage of the unique properties of each component, resulting in nanocomposites with synergistic effects to improve the charge transfer and energy storage. We found that this quaternary hybrid electrode has both high energy and power densities as well as a long cycling life in a Li/Na mixed-ion electrolyte, outperforming a multitude of other battery-supercapacitor hybrid devices reported thus far. The charge storage mechanisms of this hybrid superstructure are proposed for optimizing the electrode design.