Ultracapacitors, electronic double layer capacitors (EDLCs) or supercapacitors, are energy storage devices for high power and high cycling applications. Unlike batteries, which use a chemical reaction to store energy, ultracapacitors use a static charge. This enables ultracapacitors to fully charge and discharge in seconds while enjoying a life of up to a million or more charge and discharge cycles.
Inside the Ultracapacitor
The ultracapacitor is a relatively simple device, consisting of two symmetric carbon electrodes attached to metallic current collectors, separated by a separator material. Ultracapacitors store electric charge by separating positive and negative charges on the massive surface areas created by porous carbon electrodes. The device stores energy as static charge in the electric field the ions in the electrolyte and the surface of the carbon electrode. Electrolyte ions are attracted to the surface area of the carbon electrode; the more surface area, the greater the charge stored. In addition, larger channels in the carbon allow rapid release of the ions to improve the power performance of the device. The ultracapacitor can store orders of magnitude more energy than a conventional capacitor because the carbon electrode has an extremely high usable surface area.
Performance from Materials
Ultracapacitor performance is dictated by the performance of the ingredient materials, particularly of the carbon and the electrolyte. The high surface area activated carbons inside an ultracapacitor can contain 2,000 square meters of surface area in a single gram of material. The key to maximizing the energy in an ultracapacitor is to maximize the available surface area in the carbon.
In addition, energy stored is proportional to the square of the voltage. Voltage in ultracapacitors is limited by the presence of impurities that catalyze the breakdown of the electrolyte solvent. High purity carbons enable higher voltage and higher energy devices.
The EnerG2 Advantage
At EnerG2, we have developed the ability to tune the pore size distribution of ultrapure carbons for optimized use in ultracapacitor electrodes. EnerG2 carbons offer higher surface areas and higher levels of purity than any competing carbon, and the result is higher energy performance than in traditional ultracapacitors. Through purity levels previously unobtainable in the industry, EnerG2 materials will enable new voltage ratings on devices incorporating our products.