Graphene Hydrogel Film Adsorbed with Redox-Active Molecule Toward Energy Storage Device with Improved Energy Density and Unfading Superior Rate Capability

Abstract

Energy storage device (ESD) with enhanced energy density is desired in this electronics era, but it is often achieved at the compensation of the reduction of rate capability. To address this challenge, a hierarchical graphene hydrogel film (GHF) adsorbed with redox-active diaminoanthraquinone (DAA) molecule (DAA-GHF) was designed. The resulting DAA-GHF shows a large specific surface area and hierarchical porous structure, which can offer extra multiple charge storage and simultaneously guarantee rapid electron and ion transportation. Using the synergistic effect of DAA and GHF, DAA-GHF shows a significantly enhanced capacitance of 394.3 F g–1 at 1 A g–1 in supercapacitors and 172.3 mAh g–1 at 0.2 A g–1 in Zn ion batteries (ZIBs). Moreover, the rate capability for DAA-GHF-based supercapacitor and ZIB maintains outstanding, remaining 69.3% for supercapacitor and 52.5% for ZIB when the current density increased to 100 and 30 A g–1, respectively. Accordingly, ZIB achieves an ultrahigh power density of 28.1 kW kg–1 and presents excellent capacity retention of 92.5% after 5000 cycles. Besides, the flexible solid-state ZIB shows stable capacity under various bending states or after 500 times bending. This strategy provides a new path for fabricating high-performance films for future flexible electronic products.