Graphene-Based Inks for Flexible Supercapacitor Electrodes: A Review

In the world of consumer electronics, flexible and wearable electronic devices have witnessed a remarkable transformation, and flexible supercapacitors (SCs) hold tremendous potential as a power source for these electronic devices. Printing technologies, such as inkjet and screen printing, have emerged as cost-effective and scalable manufacturing techniques for the fabrication of flexible SC electrodes. As a key element of printing technology, ink must have the right balance of conductivity and rheological properties to fabricate high-performance flexible electrodes. Graphene stands out as a promising active pigment for conductive ink due to its remarkable characteristics such as high surface area, excellent electrical conductivity, and mechanical properties. Recently, extensive research has been conducted on the development of graphene-based inks for their effective utilization in SC printing methods. This review summarizes these advances and systematically connects the graphene ink formulation with its rheological properties and correlates finally with the electrochemical performance of inkjet- and screen-printed SC electrodes.