Synthesis and Characterization of Nanowire-Graphene Aerogel for Energy Storage Devices

Abstract

The study of graphene has become one of the most exhilarating topics in both academia and industry for being highly promising in various applications. Because of its excellent mechanical, electrical, thermal and nontoxic properties, graphene has shown promising application in energy storage devices such as lithium-ion-battery (LIB), super capacitor and solar cell. In lithium ion battery, graphite is the most commonly used material as anode. However, due to the limited specific surface area of graphite materials, the diffusion of the Li ions in the anode graphite is relatively slow, leading to limited energy storage density. In order to further increase the capacity, nano-structured materials have been extensively studied due to its potential in reducing Li-ion diffusion pathway. To date, one of the most promising approaches to improve the Li-ion diffusion rate is to introduce hybrid nanostructured electrodes that connect the nonconductive high surface area nanowire with nanostructured carbon materials. While there have been several research efforts investigated to fabricate nanowire-graphene hybrids, all the them were focused on randomly distributed nanostructures thus the LIB performance enhancement was limited. Therefore, this paper will introduce a novel hybrid structure with vertically aligned nanowire on graphene aerogel aiming to further increase the performance of LIB. The aligned nanowire array provides a higher specific surface area and could lead to high electrodeelectrolyte contact area and fast lithium ion diffusion rate. While the graphene aerogel structure is electrically conductive and mechanically robust, as well as has low specific density. The developed nanowire/graphene hybrid structure could have the potential to enhance the specific capacity and charge-discharge rate. Scanning Electron Microscopy (SEM) and X-Ray Diffraction (XRD) measurements were used for the initial characterization of this nanowire/graphene aerogel hybrid material system.