Electrochemical power sources that offer high energy and power densities and, can also withstand a harsh temperature range have become extremely desirable in applications ranging from civilian portable electronic devices to military weapons. In this report, we demonstrated a wide temperature withstanding supercapacitor which can be operated from 100 degrees C to -40 degrees C within a voltage window from -2 V to 2 V. The performance of the supercapacitor coin cells, assembled with nanostructured activated carbon fabric (ACF)as the electrode material and 1 M tetraethylammoniurn tetrafluoroborate(TEABF(4))in polypropylene carbonate (PC) solution as the electrolyte, was systematically studied within the set temperature window. The ACF supercapacitor yielded ideal rectangular shapes in cyclic voltammograms within 0-100 degrees C with an average mass capacitance of 90 Fg(-1) and, 60 Fg(-1) at -25 degrees C. The capacitance was still over 20 Fg(-1) at the extremely low temperature of -40 degrees C. Another exciting feature of the ACF supercapacitors was that they resumed their room temperature capacitance when cooled from 100 degrees C and defrosted from -40 degrees C, demonstrating an excellent repeatability and stability. The charge-discharge behavior of the ACF supercapacitors showed long-cycle stability at extreme temperatures. These high electrochemical performances make this type of supercapacitors very promising in many practical applications. (C) 2009 Elsevier B.V. All rights reserved.