posted on 2021-09-07, 19:34authored byStefano Tagliaferri, Goli Nagaraju, Apostolos Panagiotopoulos, Mauro Och, Gang Cheng, Francesco Iacoviello, Cecilia Mattevi
Three-dimensional
(3D) printing is gaining importance as a sustainable
route for the fabrication of high-performance energy storage devices.
It enables the streamlined manufacture of devices with programmable
geometry at different length scales down to micron-sized dimensions.
Miniaturized energy storage devices are fundamental components for
on-chip technologies to enable energy autonomy. In this work, we demonstrate
3D printed microsupercapacitor electrodes from aqueous inks of pristine
graphene without the need of high temperature processing and functional
additives. With an intrinsic electrical conductivity of ∼1370
S m–1 and rationally designed architectures, the
symmetric microsupercapacitors exhibit an exceptional areal capacitance
of 1.57 F cm–2 at 2 mA cm–2 which
is retained over 72% after repeated voltage holding tests. The areal
power density (0.968 mW cm–2) and areal energy density
(51.2 μWh cm–2) outperform the ones of previously
reported carbon-based supercapacitors which have been either 3D or
inkjet printed. Moreover, a current collector-free interdigitated
microsupercapacitor combined with a gel electrolyte provides electrochemical
performance approaching the one of devices with liquid-like ion transport
properties. Our studies provide a sustainable and low-cost approach
to fabricate efficient energy storage devices with programmable geometry.