Paper-based all-solid-state flexible asymmetric micro-supercapacitors fabricated by a simple pencil drawing methodology

Flexible micro-scale energy storage devices as the key component to power the flexible miniaturized electronic devices are attracting extensive attention. In this study, interdigitated asymmetric all-solid-state flexible micro-supercapacitors (MSCs) were fabricated by a simple pencil drawing process followed by electrodepositing MnO2 on one of the as-drawn graphite electrode as anode and the other as cathode. The as-prepared electrodes showed high areal specific capacitance of 220 mu F/cm(2) at 2.5 mu A/cm(2). The energy density and the corresponding power density of the resultant asymmetrical flexible MSCs were up to 110 mu Wh/cm(2) and 1.2 mu W/cm(2), respectively. Furthermore, excellent cycling performance (91% retention of capacity after 1000 cycles) was achieved. The resultant devices also exhibited good electrochemical stability under bending conditions, demonstrating superior flexibility. This study provides a simple yet efficient methodology for designing and fabricating flexible supercapacitors applicable for portable and wearable electronics. (C) 2018 Chinese Chemical Society and Institute of Materia Medica, Chinese Academy of Medical Sciences. Published by Elsevier B.V. All rights reserved.