3D solid-state supercapacitors obtained by ALD coating of high-density carbon nanotubes bundles

A three-dimensional solid-state miniaturized supercapacitor based on double conformal coating of Multiwalled Carbon Nanotubes (MWCNTs) bundles is presented. Atomic Layer Deposition (ALD) is used to deposit Al
2
O
3
as dielectric layer and TiN as high aspect-ratio conformal counter-electrode on 2μm long MWCNTs bundles. The devices are realized using an IC wafer-scale manufacturing process and show a remarkable volumetric capacitance density value of 12mF/cm
³
with high reproducibility (≤0.3E-12F deviation). The small footprint (100μm
²
to 625μm
²
), a thickness of only 2μm, the extremely high capacitance density and the novel and easy-to-integrate fabrication process make it possible to realize high performance energy storage micro-devices.