Basically I just want this to be as light as possible as it is only serving as an electrode scaffold. I already have fiber paper with 6 micron fibers that is 200 microns thick (Hollingsworth and Vose) and Lydall Technimat.
Commercial carbon fibres are normally > 6 um diameter, so I doubt there are CF formats that meet your requirement. hHve you considered nano-tubes or graphene papers?