Synergistic Fusion of Vertical Graphene Nanosheets and Carbon Nanotubes for High-Performance Supercapacitor Electrodes

Graphene and carbon nanotubes (CNTs) are attractive electrode materials for supercapacitors. However, challenges such as the substrate‐limited growth of CNTs, nanotube bundling in liquid electrolytes, under‐utilized basal planes, and stacking of graphene sheets have so far impeded their widespread application. Here we present a hybrid structure formed by the direct growth of CNTs onto vertical graphene nanosheets (VGNS). VGNS are fabricated by a green plasma‐assisted method to break down and reconstruct a natural precursor into an ordered graphitic structure. The synergistic combination of CNTs and VGNS overcomes the challenges intrinsic to both materials. The resulting VGNS/CNTs hybrids show a high specific capacitance with good cycling stability. The charge storage is based mainly on the non‐Faradaic mechanism. In addition, a series of optimization experiments were conducted to reveal the critical factors that are required to achieve the demonstrated high supercapacitor performance. Better from butter: A hybrid structure grown directly from carbon nanotubes on vertical graphene nanosheets is used to construct supercapacitors and its performance is evaluated. The intrinsic challenges inherent in both materials can be overcome through a synergistic fusion of the two structures and augments their electrochemical performance in the hybrid. This method is substrate independent and can thus be applied to a large variety of substrates.