Laser-Assisted Patterning of Co–Ni Alloy/Reduced Graphene Oxide Composite for Enhanced Micro-supercapacitor Performance

The development of methods for the facile fabrication of complex micro-supercapacitors (MSCs) has drawn much attention owing to the increment in their use in wearable and flexible microscale electronics. In particular, interdigitated MSCs with pseudocapacitive behavior have been attractive as energy storage for small-scale devices, owing to their potential to achieve high power density and excellent cycling durability within a limited area. However, complicated and multiple patterning processes are required to assemble pseudocapacitive materials and electrodes in microscale interdigitated designs. Therefore, a fabrication method is required that can be used to produce interdigitated MSCs in a facile and single-step manner. In this work, the one-pot patterning of an interdigitated Co-Ni/reduced graphene oxide (rGO) composite on a flexible substrate is presented via the infrared (IR) laser scribing of a layered double hydroxide (LDH)/graphene oxide (GO) precursor film. Owing to the homogeneous distribution of transition metal nanoparticles (NPs) within the rGO, the patterned Co-Ni/rGO electrodes show excellent electrical conductivity compared to bare rGO, which contributes toward its increased power density. In addition, the Co-Ni/rGO MSCs exhibit increased energy density compared to that of rGO MSCs due to the pseudocapacitive behavior of well-dispersed Co-Ni NPs.