Direct Ink Writing-based 3D Printing of Supercapacitors for Flexible and Wearable Electronic Applications

Abstract

Direct ink writing-based 3D printing is one of the effective methods for sustainable manufacturing of flexible and wearable electronic devices. It is gaining wide attention for soft and wearable electronics fabrication due to its several attributes like processing of a wide range of materials, flexible form factors, high scalability, less material waste, and capability to produce complex intricate structures. Here, we have reported a solid-state, asymmetric, and flexible supercapacitor fabricated using Direct ink writing (DIW) technology. The numerical simulation was used to optimize the printing parameters, and the simulation results were in good agreement with the experimental results. The rheology of the inks was also optimized for better printability. Inks for positive and negative electrodes of supercapacitors were prepared by mixing silicone with graphene-carbon nanotube composite and MnO2, respectively. The 3D-printed supercapacitors exhibited outstanding electrochemical performance within a voltage range of 0–1.8 V with poly(vinyl alcohol)-LiCl gel electrolyte. The developed device demonstrated high flexibility, reliable cycle life performance, impressive rate capability, and a high energy density. It achieved a maximum specific capacitance of 92.72 mF/cm2 at a current density of 2 mA/cm2, maximum energy density of 0.041 mWh/cm2 at a power density of 1.8 mW/cm2, and capacity retention of 89.78% even after prolonged use. This work demonstrates the high potential of the DIW method for the sustainable fabrication of supercapacitors and other electronics for next-generation flexible and wearable devices.