A research group led by WU Zhongshuai, in collaboration with WU Ren’an and BAO Xinhe from the Dalian Institute of Chemical Physics (DICP) of the Chinese Academy of Sciences (CAS), developed one-step scalable fabrication of graphene integrated micro-supercapacitors through laser scribing commercial polyimide membrane. This work was published online in Advanced Functional Materials.

The unprecedented boom of portable and wearable electronics has stimulated the demand for micro-supercapacitors (MSCs) with various properties, especially flexibility, tailored performance according to actual situations and seamless integration with existing electronics industry systems.

So far, advances of MSCs have been achieved in the development of nanostructured active materials and microfabrication techniques. However, the preparation of active materials, patterning microelectrodes and subsequent modular integration of the reported MSCs are normally separated, and involved in multiple complex steps, largely complicating fabrication process. Therefore, one-step scalable fabrication of integrated MSCs is required.

Schematic of one-step fabrication of graphene integrated micro-supercapacitors through laser scribing commercial polyimide membrane. (Image by SHI Xiaoyu and HOU Xiaocheng) 

Through laser scribing commercial polyimide membrane for simultaneous fabrication and patterning of laser induced graphene (LIG) films, the scientists demonstrated one-step, cost-effective, and scalable production of LIG micro-patterns for highly integrated MSCs (LIG-MSCs), free of metal current collectors, interconnects and extra substrate.

The produced LIG film was consisting of randomly stacked graphene nanosheets, and displayed 3D interconnected porous network, large surface area, and high electrical conductivity.

Moreover, the resulting all-solid-state LIG-MSCs not only exhibited favorable electrochemical performance, shape and size diversity, and outstanding flexibility, but also represented the fast modularization feature of producing highly integrated LIG-MSCs with adjustable voltage and current output. This was realized through customized serial and parallel arrangement of tens to hundreds of individual cells, indicative of great potential as on-chip power sources for miniaturized electronics.

Remarkably, the LIG-MSCs working in ionic liquid electrolyte could operate stably at a high temperature of 100°C for a significant long time, demonstrating their exceptional safety reliability and wide applicability.