CoO nanoflowers woven by CNT network for high energy density flexible micro-supercapacitor

Miniaturized energy storage devices have attracted considerable research attention due to their promising applications such as power-on-chip units in various smart electronic devices. In this work, a printable micro-supercapacitor (MSC) device was designed and fabricated wherein a novel three dimensional (3D) nanocomposite consisting of cobalt oxide (CoO) nanoflowers woven with carbon nanotubes (CNTs) networks were used as the active material. The CoO/CNT nanocomposites were synthesized via a high-throughput hydrothermal method. High capacitance of 17.4 F/cm(3) and energy density of similar to 3.48 mWh/cm(3) were achieved for the CoO/CNT MSC at a current density of 0.25 A/cm(3). The high volumetric energy density is attributed to the widened operation voltage window ranging from 0 to 1.2 V. Moreover, the printed CoO/CNT MSCs also showed remarkable cycling stability with similar to 85% energy density retention after 1700 cycles and high mechanical flexibility which can function well even after bending up to 180 degrees. As a result, the printed CoO/CNT MSC is a possible contender in future energy storage devices for low-cost on-chip power applications. (C) 2013 Elsevier Ltd. All rights reserved.