Abstract
Vertical graphene (VG), possessing superior chemical, physical, and structural peculiarities, holds great promise as a building block for constructing a high-energy density lithium-sulfur (Li-S) battery. Therefore, it is desirable to develop a new VG growth technique with a novel structure to enable wide applications. Herein, we devise a novel complex permittivity-dependent plasma confinement-assisted VG growth technique, via asymmetric growing a VG layer on one side of N-doped carbon nanofibers for the first time, using a unique lab-built high flux plasma-enhanced chemical vapor deposition system, as a bifunctional nanofiber membrane to construct Li-S batteries with low negative/positive (N/P) and electrolyte/sulfur (E/S) ratios. The unique nanofiber membrane could simultaneously protect the cathode and anode, enabling an excellent electrochemical performance with low N/P and E/S ratios in Li-S batteries. Such a full cell delivers high gravimetric energy density and volumetric energy density of 340 Wh kg(-1) and 547 Wh L-1, respectively, at low N/P (2:1) and E/S (4:1) ratios. Furthermore, a pouch cell achieves a high areal capacity of 7.1 mAh cm(-2) at a sulfur loading of 6 mg cm(-2). This work put forward a novel pathway for the design of high-energy density Li-S batteries.