3D graphene oxide gel assembly: Effects of nanosheet morphology and ammonia on gel properties and their use as structural electrodes for energy storage
Smit A. Shah (1), Dorsa Parviz (2), Morgan G. Odom (3), Wanmei Sun (1), Devon Kulhanek (1), Micah J. Green (1,3)
1. Chemical Engineering, Texas A&M University, College Station, TX
2. Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA
3. Materials Science and Engineering, Texas A&M University, College Station, TX
3D graphene oxide (GO) based gels synthesized using sol-gel technique have gained remarkable interest because of their ability to retain individual nanosheet properties. The high specific surface area and electrical conductivity of these 3D gel networks makes them suitable active material for electrochemical energy storage applications. However, 3D GO gel’s electrical conductivity, surface area and density depend on the crosslink type and density. Here we investigate the role of ammonia and precursor nanosheet morphology on the crosslink type and density of 3D GO gels. Our results indicate that ammonia strongly affects the formation of inter-sheet bridging structures as well as the deoxygenation and reduction of nanosheets during gelation. Thermal annealing of GO gels result in an increase in their electrical conductivity and displacement of nitrogen. We also altered the GO nanosheet morphology to obtain crumpled GO (CGO) nanosheets and prepared 3D aerogels with mixtures of GO-CGO nanosheet dispersions. The properties of these gels demonstrate how the GO morphology can allow for an additional handle in creating GO-based gels with tunable density, electrical conductivity, and surface area. We investigated the composites of GO gel with aramid nanofibers (ANFs) to obtain improved mechanical properties for their application as structural supercapacitor electrodes.
Keywords: Sol-gel synthesis, Polymer-nanomaterial composites, Structural electrodes