Highly Compressible Macroporous Graphene Monoliths via an Improved Hydrothermal Process

Abstract

An improved hydrothermal process is developed to fabricate macroporous graphene monoliths (MGMs) using a soft template of organic droplets. The MGMs are constructed from closed-cell distorted spherical pores. This unique microstructure makes MGMs that have low weight densities, good electrical conductivities, and excellent elasticity with rapid recovery rates.

Three-dimensionally bonded spongy graphene material with super compressive elasticity and near-zero Poisson’s ratio

“…Substantially reversible deformation was retained even for a compression ratio (ratio of initial to final length) of 50 (corresponding to B98% strain) shown in the inset of Fig. 3a and Supplementary Movie 2, which appears to be largest isotropic elastic deformability reported so far for any form of carbon 2,4,7,9,42 . During 1,000 compression cycles in air to 90% strain (Fig.…”

Fluorosurfactants‐Directed Preparation of Homogeneous and Hierarchical‐Porosity CMP Aerogels for Gas Sorption and Oil Cleanup

“…To date, for almost all aerogels, the emphasis has been placed on the chemical composition,13 solvent,14, 15 and some general reaction conditions (temperature, time, and pressure) 16. The gel with homogeneous chemical composition can be easily obtained without considering environmental atmosphere in the reaction process.…”

High porosity scaffold composites of graphene and carbon nanotubes as microwave absorbing materials

“…During the hydrothermal process the graphene oxide sheets are reduced and assembled around the hexane droplets which act as soft templates for macroporous structures. 19 The hybrid aerogels exhibit a three-dimensional network structure composed of hierarchical distribution of pores. SEM images shown in Fig.…”

“…The strong p-p stacking interaction existing between graphene planar fragments and between graphene and CNTs provides an exceptional stability to the 3D network of the resulting hybrid material. 18 To control the pore size and to obtain hierarchical pore morphology we have modified an already reported hydrothermal method 19 which involves the preparation of stable aqueous emulsions of graphene oxide containing hexane droplets. A subsequent careful cold evaporation of hexane followed by lyophilisation of the aqueous phase allows us to achieve more consistent scaffold structures and displaces and compresses the CNT-rGO towards the walls of the ice crystal structure increasing the CNT connectivity and, consequently, the conductivity of the material.…”

“…The emulsion was sealed in a 20 mL Teflon autoclave and maintained at 180 1C for 10 h; afterwards the autoclave was naturally cooled to room temperature and the hexane containing gel was removed. Attempts to remove hexane solvent via the hot water treatment 19 were not successful because of the collapse of the macropores. Alternatively, we found that a previous hexane cold evaporation under vacuum with the scaffold, frozen at 10 1C, was a successful approach.…”