Direct Graphene‐Carbon Nanotube Composite Ink Writing All‐Solid‐State Flexible Microsupercapacitors with High Areal Energy Density

Abstract The advancement of miniaturized electronic devices requires the development of high‐performance microsupercapacitors. The low areal energy density of microsupercapacitors with the interdigitated architecture is the major challenge hindering the application. Here, a simple method for the scalable fabrication of all‐solid‐state, flexible microsupercapacitors is demonstrated by direct graphene‐carbon nanotube composite ink writing technology. The microsupercapacitors demonstrate good electrochemical performance with a high areal energy density of 1.36 µWh cm –2 and power density of 0.25 mW cm –2 , good cycling stability, and excellent mechanical flexibility. The method developed here sheds light on the simple method of preparing high‐performance, all‐solid‐state, flexible microsupercapacitors in a straightforward and scalable process.