Multiplying Energy Storage Capacity : In Situ Polypyrrole Electrodeposition for Laser-Induced Graphene Electrodes

Scalability and automation are two cornerstones for advanced manufacturing where laser-induced graphene (LIG) can play a key role. However, it is well known that LIG, employed as an electrode material for electrochemical storage devices, has a severely limited energy storage capability, thus presenting a major roadblock to mass commercial adoption. Herein, a technique based on the in situ electrodeposition of polypyrrole (PPy) onto three-dimensional (3D) porous LIG (LIG@PPy) is proposed for overcoming the inherent charge storage limit of LIG. For demonstration, zinc-ion hybrid microsupercapacitors (ZHMSCs) have been realized by integrating LIG@PPy cathodes with Zn anodes. As a key advantage, the conformal deposition of PPy with high specific capacity significantly enhances the charge storage capacity of the LIG skeleton and improves conductivity while maintaining the structural integrity of the porous structure to ensure fast charge diffusion kinetics. Further benefiting from the use of multivalent ions and asymmetrical electrodes, the prototyped ZHMSC exhibits a wide voltage window (1.7 V) and a remarkable areal capacitance/energy density (149 mF cm^-2/54 μWh cm^-2), which represents a 200× enhancement from the pristine LIG counterpart. This work provides a simple strategy for unlocking the full energy storage potential of LIG without sacrificing any of its existing advantages, overcoming a major bottleneck that had plagued LIG as a practical cathode material for microsupercapacitors and other energy storage devices.