Dried figs like nitrogen-doped graphene oxide anchored cobalt-doped Fe3O4 nanoparticle as sulfur host for high performance Li-S battery

Abstract

Lithium-sulfur batteries (LSBs) represent a prospective energy storage device because of their low cost and high theoretical energy density. However, the performance of LSBs was largely constrained by the kinetics of polysulfides (LiPSs) conversion and shuttle effect. Thus, a metal-doped metal oxide is proposed as an efficient adsorbent and catalyst for LiPSs. We designed cobalt-doped Fe3O4 nano-catalysts which was in situ grown on the N-doped graphene conductive network as a multifunctional sulfur host. Evidenced by experimental characterization, it is demonstrated that due to the appropriate doping amount (EGO/Co-Fe3O4 (700)), the host exhibits efficient adsorption and rapid catalytic conversion of LiPSs. Compared with the undoped Co catalyst (S@EGO/Fe3O4), The S@EGO/Co-Fe3O4 (700) electrode possesses high initial discharge specific capacity (1488.4 mAh/g, 0.2 C), and superior cycle stability (900.8 mAh/g after 100 cycles). Impressive performances are also attained at lean electrolyte conditions (electrolyte-to-sulfur (E/S) ratio ∼ 7 μL mg−1).