Conjugated molecule functionalized graphene films for energy storage devices with high energy density

Abstract

The design of electrode materials is critical to improve electrochemical performance of supercapacitors. Here, 3,4,9,10-perylene-tetracarboxylicacid-dianhydride (PTCDA) molecule functionalized reduced graphene oxide (rGO) self-supporting film with fluffy and porous structure is built by simple and green processes. Due to the synergistic effect between PTCDA molecule with fast Faradaic reaction and fluffy rGO skeleton with excellent ion transport performance, the as-fabricated PTCDA/rGO film electrode exhibits significantly improved electrochemical performance compared with rGO electrode in the symmetric supercapacitor and zinc-ion hybrid supercapacitor, including gravimetric capacitance of 242.9 F g−1 at 2 A g−1 in Li2SO4 aqueous electrolyte and discharge capacity of 162.8 mAh g−1 at 1 A g−1 in ZnSO4 aqueous electrolyte. Besides, the symmetric supercapacitor based on PTCDA/rGO film electrodes delivers a gravimetric energy density of 19.7 Wh kg−1 at an ultra-high gravimetric power density of 45 kW kg−1, and the zinc-ion hybrid supercapacitor based on PTCDA/rGO cathode delivers an extremely high gravimetric energy density of 120.5 Wh kg−1 at a gravimetric power density of 740.1 W kg−1. This work provides practical strategy to construct the synergistic relationship between the structure and composition of electrode materials, and explores the influence of this strategy on the electrochemical performance of symmetric and hybrid supercapacitors.