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

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 in-plane 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 μW 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. •Photo-reduction technique was used for the first time to fabricate rG-O MSCs.•Selective electrodeposition of Co–Mn LDHs to fabricate HMSCs.•HMSCs exhibited high specific capacitance of 36.38 mF cm−2 and energy density of 6.82 μW h cm−2 at current density of 0.71 mA cm−2•HMSCs exhibited an excellent cycling stability up to 10,000 cycles.