Optimization Strategy of Molecular Modified Graphene Films for High-Performance Aqueous Zinc-Ion Hybrid Supercapacitors

Abstract

Molecular modified graphene films (M-GFs) have the advantages of simple preparation and high electrochemical activity, which has a promising future in the field of electrochemical energy storage. However, the influence of molecular doping technology is rarely studied for electrochemical performance of the M-GFs, hindering the development of high-performance M-GFs. Herein, we have demonstrated that a selective adsorption self-assembly strategy can prepare M-GFs with higher performance than physical mixing method. The prepared M-GF exhibits a three-dimensional porous structure with active organic molecules support, and its interlayer spacing is evenly widened. The resulting M-GFs as cathode material of aqueous Zinc-ion hybrid supercapacitors (AZISCs) exhibits a high specific capacitance of 228F g-1, and a good capacitance retention of 42% (@10 A g-1), which are 25% and 13% higher than those of the physical mixing method, respectively. Besides, the energy and power density of the devices can reach 82 Wh kg-1 and 20.3 kW kg-1, respectively. After 5000 cycles of charge and discharge testing, the capacitance retention rate of the device can still reach 94%. The impressive results indicate that the M-GFs by selective adsorption self-assembly strategy could be a potential high-performance electrode material for the AZISCs..