3D printing of high-performance micro-supercapacitors with patterned exfoliated graphene/carbon nanotube/silver nanowire electrodes

Micro-supercapacitors (MSCs) show great potential as on-chip energy storage devices for portable electronics. The major flaw of thin-film MSCs is their low energy density. To improve the energy density, thicker electrodes are required. However, the fabrication of MSCs with thick electrodes remains a challenge. In this work, a novel 3D printing method is employed to fabricate high-performance MSCs with interdigitated exfoliated graphene (EG)/carbon nanotube (CNT)/silver nanowire (AgNW) electrodes. The nanowelding of AgNW junction plays a critical role in the realization of 3D printing. To enhance the electrochemical performances of EG, phosphorus atoms are incorporated into the carbon framework with 1.7 at%. The areal capacitance of the 3D printed MSC is 21.6 mF cm−2 at a scan rate of 0.01 Vs−1. The areal energy density of the MSC ranges from 0.5 to 2 µWh cm−2 with a maximum power density of 2.5 mW cm−2.