Oxidation‐Resistant and Elastic Mesoporous Carbon with Single‐Layer Graphene Walls

Abstract

An oxidation-resistant and elastic mesoporous carbon, graphene mesosponge (GMS), is prepared. GMS has a sponge-like mesoporous framework (mean pore size is 5.8 nm) consisting mostly of single-layer graphene walls, which realizes a high electric conductivity and a large surface area (1940 m 2 g −1 ). Moreover, the graphene-based framework includes only a very small amount of edge sites, thereby achieving much higher stability against oxidation than conventional porous carbons such as carbon blacks and activated carbons. Thus, GMS can simultaneously possess seemingly incompatible properties; the advantages of graphitized carbon materials (high conductivity and high oxidation resistance) and porous carbons (large surface area). These unique features allow GMS to exhibit a suffi cient capacitance (125 F g −1 ), wide potential window (4 V), and good rate capability as an electrode material for electric double-layer capacitors utilizing an organic electrolyte. Hence, GMS achieves a high energy density of 59.3 Wh kg −1 (material mass base), which is more than twice that of commercial materials. Moreover, the continuous graphene framework makes GMS mechanically tough and extremely elastic, and its mean pore size (5.8 nm) can be reversibly compressed down to 0.7 nm by simply applying mechanical force. The sponge-like elastic property enables an advanced force-induced adsorption control.

Hydrogen Storage in Porous Materials: Status, Milestones, and Challenges

“…This could be a novel option for the design of materials for energy storage. In this sense, we have shown by using Synchrotron radiation that ACFs present a flexible porous network which pore size is modified by applying uniaxial tensile forces along the fiber main axis, being this change reversible A recent report by Nishihara et al . has shown a highly flexible graphene mesosponge (GMS) which might be very interesting for H 2 storage applications considering that it has the possibility of tailoring the porosity.…”

3D Carbon Materials for Efficient Oxygen and Hydrogen Electrocatalysis

“…In recent years, carbon materials (i.e., graphene, carbon nanotubes (CNTs), graphitic arrays, and other nanostructures) have been developed as promising cost‐effective alternatives for promoting oxygen and hydrogen electrocatalysis in energy technologies . In particular, 3D carbon architectures, with tunable porous structures, offer extraordinary mass and electron transport capabilities, which are extremely attractive for electrocatalysis in energy conversion and storage systems . In the last decade, major breakthroughs in the field of metal‐free carbon electrocatalysts have been achieved, making the creation of a new generation of energy devices based on cost‐efficient sustainable metal‐free carbons possible ( Figure 1 ).…”

Optimization of Electrode Potential Ranges for Constructing 4.0 V Carbon‐Based Supercapacitors

“…Note that the relatively rapid capacitance decline in the first 500 cycles should be ascribed to the irreversible side reactions caused by the high-electrochemical-activity defects on APDC-6. [34][35][36][37] Figure 4d shows cycling performance of SC with a m + /m À of 1.3 : 1, which was inferior to that of SC with a m + /m À of 1.2 : 1. This is because the excessive mass of positive electrode made its potential change too slow, thus the potential of negative electrode exceed P L .…”

“…As shown in Figure c, the device showed good cycling stability over 5000 cycles with nearly 100 % coulombic efficiency. Note that the relatively rapid capacitance decline in the first 500 cycles should be ascribed to the irreversible side reactions caused by the high‐electrochemical‐activity defects on APDC‐6 . Figure d shows cycling performance of SC with a m + /m − of 1.3 : 1, which was inferior to that of SC with a m + /m − of 1.2 : 1.…”