Graphene Micro-Supercapacitors
Co-I Garrett Frankson and Austin Jeffries
Current Status: Building Project Page
Project Overview
A capacitor is an electric energy storage device, often constructed with two layers of conducting foil separated by a paper-thin layer of insulator. The capacity is proportional to the area A and inversely proportional to the insulator thickness t, C~A/t. A supercapacitor has a atomic scale insulator thickness given by the solvation layer surrounding an ion in an electrolyte, and a large surface area. Supercapacitor values of 1-1000 F are now available commercially and approach the energy density of batteries while offering fast charge and discharge rates (high power density). For an introduction to graphene based supercapacitors, see http://vimeo.com/51873011. -duncan
Project Goals
Construct a supercapacitor.
Relevant Publications
Maher F. El-Kady & Richard B. Kaner
El-Kady and Kaner demonstrate a scalable fabrication of graphene micro-supercapacitors over large areas by direct laser writing on graphite oxide films. More than 100 micro-supercapacitors can be produced on a single disc in 30 min or less. The devices are built on flexible substrates for flexible electronics and on-chip uses. Remarkably, miniaturizing the devices to the microscale results in enhanced charge-storage capacity and rate capability. These microsupercapacitors demonstrate a power density of ~200 W cm-3, which is among the highest values achieved for any supercapacitor.
Preparation of Graphitic Oxide
William S. Hummers & Richard E. Offema
- The conventional method for the preparation of graphitic oxide is time consuming and hazardous. Hummers and Offema have developed a rapid, relatively safe method for preparing graphitic oxide from graphite in what is essentially an anhydrous mixture of sulfuric acid, sodium nitrate and potassium permanganate.
- Nina I. Kovtyukhova et al.
- For the synthesis of graphitic oxide, El-Kady and Kaner used a modified Hummers' method developed by Nina I. Kovtyukhova et al.