Aqueous Organic Zinc-Ion Hybrid Supercapacitors Prepared by 3D Vertically Aligned Graphene-Polydopamine Composite Electrode

A three-dimensional vertical-aligned graphene-polydopamine electrode (PDA@3DVAG) composite with vertical channels and conductive network is prepared by a method of unidirectional freezing and subsequent self-polymerization. When the prepared PDA@3DVAG is constructed as the positive electrode of zinc-ion hybrid supercapacitors (ZHSCs), excellent electrochemical performances are obtained. Compared with the conventional electrolyte, PDA@3DVAG composite electrode in highly concentrated salt electrolyte exhibits better multiplicity performance (48.92% at a current density of 3 A g(-1)), wider voltage window (-0.8~0.8 V), better cycle performance with specific capacitance from 96.7 to 59.8 F g(-1), and higher energy density (46.14 Wh kg(-1)).

Automated summary

A three-dimensional vertical-aligned graphene-polydopamine electrode composite with vertical channels and conductive network is prepared using a method of unidirectional freezing and subsequent self-polymerization. When used as the positive electrode in zinc-ion hybrid supercapacitors (ZHSCs), it exhibits excellent electrochemical performances, including better multiplicity performance, wider voltage window, better cycle performance, and higher energy density.