CSIRO Ultra Battery, page-10

https://ieeexplore.ieee.org/document/4601215/

Abstract:
The development of high density integrated capacitors is crucial for the implementation of high performance mixed-signal integrated circuits. In this paper, we propose three possible high density integrated capacitor configurations based on multi-walled carbon nanotubes (MWCNT). We develop an RLC model for the MWCNT-based capacitor configurations and examine the design trade-off between capacitance per area and losses due to parasitic resistance and inductance.
The results indicate that the proposed MWCNT based capacitor configurations can potentially offer orders of magnitude larger capacitance per area and comparable quality factors to traditional metal-based integrated capacitors.


Yes I admit this document is dated, but there is a lot more out there on the ieeexplore site that is much more recent, but I can't access it.