Carbon Nanofibers (CNFs) Coated Ni Foam As 3D Integrated Current Collector and Sulfur Host in Li-S Batteries

Abstract

Tremendous attention has been paid to the energy conversion and storage devices for their rapidly growing market and more requirement for nowadays’ applications, ranging from portable electronics, electric tools to large renewable energy systems. The high theoretical capacity (1672 mAh g-1) and energy density (2600 Wh kg-1) for sulfur electrode make it be a very promising candidate for electric and hybrid electric vehicles among the various candidates. However, the commercialized process for this promising material is still greatly hindered by a series of issues, including the insulating of sulfur, large volume change, and the “shuttle effect” of polysulfides. With this in mind, we developed the CNFs coated Ni foam both as the sulfur host and the current collector. The Ni foam was coated with two types of carbon layers. The inner one is relatively compact carbon layer rich in micropores, and the outer one is carbon nanofiber layer. After heat treatment at elevated temperature, sulfur was either physically impregnated into the micropores or chemically bond to C and Ni atoms. The surface and cross-section morphology were characterized by SEM and TEM and the chemical bond states were analyzed by XPS. The 3D conductive network, micropores, and chemical binding synthetically resulted in the high stability and excellent rate capability of the electrode, showing the potential application in developing high-performance Li-S batteries.