EAPSI: Characterizing energy storage in supercapacitors using atomically thin carbon sheets (Graphene)

Huffstutler Jacob D, Carbondale IL

Investigators

Abstract

Current challenges in energy storage technology require more than batteries and capacitors. These devices suffer from several deficiencies when applications require simultaneously handling large amounts of energy and doing so quickly. Supercapacitors are a potential solution due to their strong performance in both power and energy comparisons. The flexibility of supercapacitors to handle moderate amounts of energy faster than batteries makes them ideal for use in a variety of applications. Recent studies show graphene, a single layer of carbon in a honeycomb arrangement, performs particularly well as the electrode material for supercapacitors. This project will seek to explore the behavior of graphene and map the behavior from single to multilayer. This research will be conducted at the National Synchrotron Research Laboratory, in collaboration with Dr. Li Song and will only be made possible through the finely-tuned graphene growth capabilities exhibited there. Carbon materials are commonly used as the electrode material for the construction of supercapacitors, and graphene stands out as a strong candidate given its 2D structure and vast specific surface area. However, graphene synthesis is complicated due to the Van der Waals interactions between the 2D layers, causing layers to agglomerate into a bulk material. The behavior as the system moves from the nanoscale to the macroscale changes significantly. Often methods are used to shear these layers apart mechanically, chemically, or through liquid-phase exfoliations. These "top down' processes are often limited in product quality or quantity. Samples will be characterized with Tunneling Electron Microscopy and X-Ray Photoelectron Microscopy. This study will allow for the accurate mapping of the behavior of devices using Cyclic Voltammetry, Galvanostatic Charge-discharge, and Electrochemical Impedance Spectroscopy. This NSF EAPSI award is funded in collaboration with the Chinese Ministry of Science and Technology.