3D carbon based nanostructures for advanced supercapacitors

Abstract

Supercapacitors have attracted intense attention due to their great potential to meet the demand of both high energy density and power density in many advanced technologies. Various carbon-based nanocomposites are currently pursued as supercapacitor electrodes because of the synergistic effect between carbon (high power density) and pseudo-capacitive nanomaterials (high energy density). This feature article aims to review most recent progress on 3D (3D) carbon based nanostructures for advanced supercapacitor applications in view of their structural intertwinement which not only create the desired hierarchical porous channels, but also possess higher electrical conductivity and better structural mechanical stability. The carbon nanostructures comprise of CNTs-based networks, graphenebased architectures, hierarchical porous carbon-based nanostructures and other even more complex carbon-based 3D configurations. Their advantages and disadvantages are compared and summarized based on the results published in the literature. In addition, we also discuss and view the ongoing trends in materials development for advanced supercapacitors. Broader contextSupercapacitors are one of the crucial devices for energy storage applications as they can provide higher power density than batteries and higher energy density than conventional dielectric capacitors. Many materials have been investigated as electrode materials for supercapacitors. Among them, carbon materials with various microtextures are considered as the main candidate for supercapacitors in terms of high surface area, interconnected pore structure, controlled pore size, high electrical conductivity and environmental friendliness. Nevertheless, pure carbon materials encounter difficulties in meeting the requirements of high energy storage devices even with the ne-tuned pore structures due to their energy storage mechanism which is a purely physical process. To further improve the energy density of supercapacitors without sacrice of power density, carbon-based composites combining electrical double layer capacitance and pseudocapacitance have been extensively explored, demonstrating enhanced capacitance as well as good cycling stability. In this review, recent progress on the 3D carbon based nanostructures encompassing the CNTs-based networks, graphene-based architectures, hierarchical porous carbon-based nanostructures and even more complex carbon-based 3D conguration for advanced supercapacitor applications is summarized, shedding light on their structural interconnectivities, which not only create hierarchical porous channels, but also lead to higher electrical conductivity and better structural mechanical stability. Their advantages and disadvantages are discussed, new trends of electrode materials for high-performance supercapacitors are also proposed.

Supercapacitors specialities - Materials review

“…Other recent reviews related to supercapacitor materials are available [105][106][107][108][109]. Many reported results refer to nanostructured carbon based materials and different related composites used for the manufacture of experimental supercapacitor electrodes.…”

Recent progress in carbon-based nanoarchitectures for advanced supercapacitors

“…Compared to conventional porous carbon materials, 3D carbon-based nanostructures possess hierarchical porous paths, superior electrical conductivity, and stable structural mechanical property. Moreover, the 3D nanoscale designs could not only deliver continuous electron paths to guarantee excellent electrical accessibility, but also accelerate ion transfer through shortening diffusion paths in 3D hierarchical porous nanostructures with different wellinterconnected pore models, which can be acceptable for high-performance electrode materials of SCs [110,136]. Hence, it is advisable to design and fabricate novel 3D carbon-based nanostructures by integrating the benefits of various carbon building blocks.…”

“…So far, fruitful researches have confirmed its potential application as the electrode materials of SCs. The valid specific surface area of graphene as a capacitive material highly relies on the number of graphene layers [110]. Theoretically, the parallel plates could offer enormous paths through which electrolyte ions can easily approach the surface of each graphene layers with reduced diffusion resistance.…”

Faradaic and Capacitive Components of the CNT Electrochemical Responses

“…At the moment, it does not exist a widely accepted mechanism to explain the CNT electrochemical responses. It has been broadly accepted that they include mainly capacitive or physical effects, where balancing counter ions are oriented and disposed to compensate the excess of charges on their surface, but not changing the composition inside the CNTs bundles (Baughman et al, 1999;Riemenschneider et al, 2009a,b;Jiang et al, 2013). The almost square shape of the voltammetric responses in short potential ranges constitutes the main support of the claimed capacitive nature.…”