Preparation and Electrochemical Performance of Three-Dimensional Vertically Aligned Graphene by Unidirectional Freezing Method

Three-dimensional vertically aligned graphene (3DVAG) was prepared by a unidirectional freezing method, and its electrochemical performances were evaluated as electrode materials for zinc-ion hybrid supercapacitors (ZHSCs). The prepared 3DVAG has a vertically ordered channel structure with a diameter of about 20-30 mu m and a length stretching about hundreds of microns. Compared with the random structure of reduced graphene oxide (3DrGO), the vertical structure of 3DVAG in a three-electrode system showed higher specific capacitance, faster ion diffusion, and better rate performance. The specific capacitance of 3DVAG reached 66.6 F center dot g(-1) and the rate performance reached 92.2%. The constructed 3DVAG zinc-ion hybrid supercapacitor also showed excellent electrochemical performance. It showed good capacitance retention up to 94.6% after 3000 cycles at the current density of 2 A center dot g(-1).

Automated summary

Three-dimensional vertically aligned graphene (3DVAG) prepared by a unidirectional freezing method shows a vertically ordered channel structure and exhibits superior electrochemical performances compared to random structure reduced graphene oxide (3DrGO), including higher specific capacitance, faster ion diffusion, and better rate performance. The constructed 3DVAG zinc-ion hybrid supercapacitor also demonstrates excellent electrochemical performance.