High-performance hybrid microsupercapacitors based on Co-Mn layered double hydroxide nanosheets

Abstract

Although miniaturized energy storage devices have emerging applications in portable and highly integrated electronic circuits, it is still challenging to develop fast and low-cost techniques to fabricate such micro-devices at an industrial scale. In this work, we report a novel, fast and environment-friendly photo-reduction technique to fabricate interdigitated graphene-based microelectrode patterns for inplane microsupercapacitors (rG-O MSCs). Further selective electrodeposition of Co-Mn layered double hydroxide (CMLDH) on the interdigitated graphene microelectrodes is carried out for the fabrication of hybrid MSCs (HMSCs). The uniform deposition of three-dimensional vertical nanosheets of CMLDH provide more assessable active sites for electrolyte ions, which lead to a fast redox reaction, short ion diffusion length, and one-dimensional electron transport. The as-fabricated CMLDH HMSC exhibit high specific capacitance (36.38 mF cm(-2)) and energy density (6.82 mu W h cm(-2)) at a current density of 0.71 mA cm(-2) in 2 M KOH aqueous electrolyte. In addition, the CMLDH HMSC exhibit an excellent cycling stability up to 10,000 cycles. These findings pave the way for scalable low-cost fabrication of flexible high-performance MSCs. (C) 2019 Elsevier Ltd. All rights reserved.