Investigation on Gd Doped BFO as a Stabilizer for Capacity Retention of CNT-Sulfur Composite Electrodes of Li-S Batteries

In this work, bismuth ferrite powder modified via Gadolinium (Gd) with spontaneous polarization is adopted to modify the carbon nanotube (CNT)-sulfur composite cathode owing to its special interaction with polysulfides. We synthesized these composite cathodes via ball milling of Sulfur and CNTs and Gd-doped BiFeO3 (BFO) was coated on a polypropylene separator. As a matter of fact, Gd-modified BFO in interaction with CNT-sulfur composite acts as a stabilizer to develop a stable cathode. However, carbon nanotubes have distinct qualities like high aspect ratios, increased surface area, and high surface-to-volume ratio. Our results show that Gd-modified BFO in interaction with CNT-sulfur composite cathode can effectively suppress the shuttling of polysulfides and then greatly improve the electrochemical properties of the lithium-sulfur battery in terms of cycle stability, rate performance, reaction kinetics, self-discharge behavior.