Indeed, I read the abstract: >we stabilize a rare monoclinic γ-sulfur phase within carbon nanofibers and my mind jumped to "sulfur inside a nanotube again". B

Indeed, I read the abstract: >we stabilize a rare monoclinic γ-sulfur phase within carbon nanofibers and my mind jumped to "sulfur inside a nanotube again". But the sulfur isn't "within" the carbon nanofibers, as they later specify, and this is new. >We demonstrate that despite an exposed “un-confined” deposition of this sulfur phase on the host carbon material, the carbonate-based battery exhibits high reversible capacity The sulfur is in contact with the electrolyte. And it works! That's not supposed to happen, but now it does. So the process you described doesn't make carbon nanotubes, it makes nanofibers, which are much simpler (you don't need axial concentric planes).