Boosting the performance of flexible in-plane micro-supercapacitors by engineering MoS2 nanoparticles embedded in laser-induced graphene

As an essential miniature energy storage device, flexible in-plane micro-supercapacitors (MSCs) have the advantages of rapid charge and discharge, instantaneously high power output, long cycle stability and easy integration. However, the synthesis of electrode materials, the preparation of patterned microelectrodes and the subsequent modular integration are usually carried out independently, and the steps are very complicated. Accordingly, an effective and fast fabrication process involving laser direct writing technique is introduced to prepare shape-controllable MoS2 nanoparticle-embedded laser-induced graphene (MoS2/LIG) patterned electrodes on various substrates for flexible planar MSCs. The embedding of MoS2 nanoparticles can effectively improve the hydrophobic properties of MoS2/LIG hybrid electrodes, which is more conducive to the adsorption and desorption of aqueous electrolyte ions. Benefiting from the engineering of pseudocapacitive MoS2 nanoparticles uniformly embedded in good conductive LIG with 3D porous structure, our flexible planar MoS2/LIG MSC demonstrates a superior areal capacitance of 35.3 mF cm(-2), a high energy density of 4.91 mW h cm(-2) at a power density of 0.18 mW cm(-2), good cycle stability, outstanding mechanical flexibility, and prominent modular integration. The universal process route developed in this work can be used for controllable assembly of many similar flexible planar integrated MSCs, and may accelerate their potential application in flexible and wearable electronics. (C) 2021 Elsevier B.V. All rights reserved.