Printed supercapacitors were prepared to be applied as a part of a hybrid power source in printed electronics applications. The use of non-toxic materials was preferred. The supercapacitor structure consisting of current collectors and activated carbon electrodes was applied on paperboard substrate using silver, graphite and activated carbon inks. Aqueous electrolytes with NaCl salt limit the maximum potential to about 1.2 V but are environmentally friendly and provide low equivalent series resistance (ESR). The capacitance values of our printed supercapacitors were typically 0.1-0.5 F. With 2 cm(2) geometrical active area the ESR was below 1 Omega which is acceptable for 50 mA current output. The efficiency with 50 mA charge and discharge current was typically about 90% and with 10 mA about 95%. (C) 2012 Elsevier Ltd. All rights reserved.