Bundaleska, N.Felizardo, E.Santhosh, N. M.Upadhyay, K. K.Bundaleski, N.Teodoro, O. M. N. D.Botelho do Rego, A. M.Ferraria, A. M.Zavašnik, J.Cvelbar, U.Abrashev, M.Kissovski, J.Mão de Ferro, A.Gonçalves, B.Alves, L. L.Montemor, M. F.Tatarova, E.2025-02-052025-02-052024-12-150169-4332PURE: 102068191PURE UUID: a14bdce3-8709-44ee-9df6-758e96cf5b54Scopus: 85201605128WOS: 001299930300001ORCID: /0000-0002-3424-2847/work/177441926http://hdl.handle.net/10362/178489UC, NMS and JZ acknowledge the Slovenian Research Agency ( ARIS ) for the projects Z2-4467 , J2-50074 and program No. P1-0417 and EU Graphene Flagship FLAG-ERA III JTC 2021 project VEGA ( PR-11938 ) and M-ERA.NET 3 project ANGSTROM (The project is funded by Ministrstvo za visoko solstvo, znanost in inovacije \u2013 MVZI, Slovenia). Publisher Copyright: © 2024 The Author(s)Self-standing vertically oriented carbon nanostructures (VCNs) were synthesized using a large-scale microwave plasma under low-pressure conditions, employing methane as a carbon precursor. The influence of plasma operational and substrate conditions on nanostructure growth and morphology were systematically studied. Furthermore, post-synthesis N-doping of VCNs with nitrogen content of 2.4 at% N was achieved using an Ar-N2 microwave plasma. Plasma-enabled direct deposition of VCNs, both doped and un-doped, onto nickel foils has been accomplished. The assessment of the developed nanostructures as electrodes in high-frequency AC filtering capacitors, has demonstrated an overall capacitance of approximately 480 µF at 100 Hz, with a cut-off frequency of 4 kHz for a phase angle of −45°. The excellent electrochemical performance can be attributed to the appropriate structural and morphological properties peculiar for the directly deposited on nickel foil VCNs providing binder-free electrode fabrication, thus enhancing the electrode's conductivity and charge transfer kinetics. This plasma-enabled approach for electrode design on a large scale, coupled with excellent filtering performance, paves the way for many applications in high-frequency scenarios, offering an environmentally friendly alternative to conventional electrolytic capacitors.129516688engBinder-free electrodesHigh-frequency AC filtering capacitorsMicrowave plasma growthPlasma post-synthesis N-dopingVertically oriented carbon nanostructuresCondensed Matter PhysicsSurfaces and InterfacesSurfaces, Coatings and Filmsjournal article10.1016/j.apsusc.2024.161002https://www.scopus.com/pages/publications/85201605128https://www.webofscience.com/api/gateway?GWVersion=2&SrcApp=nova_api&SrcAuth=WosAPI&KeyUT=WOS:001299930300001&DestLinkType=FullRecord&DestApp=WOS_CPL