Ferrous sulfide-assisted hollow carbon spheres as sulfur host for advanced lithium-sulfur batteries

Lithium-sulfur (Li-S) batteries have attracted extensive interests for its high theoretical energy density, but its further applications are blocked by capacity loss as a result of the shuttling of lithium polysulfides (LiPSs). A ferrous sulfide-stabilized S-hollow carbon sphere group (BP2000-FeS-S) was fabricated by supporting conductive ferrous sulfide (FeS) into a hollow carbon sphere group (BP2000), followed by traditional wet-impregnating of S. The BP2000 host physically confines LiPSs while FeS is anchored inside BP2000 and further chemically interact with LiPSs through bonding with FeS. Meanwhile, FeS acts as the filling inside the hole of BP2000 adjusting an appropriate aperture size to restricting the drain of S/LiPSs. The BP2000-FeS-S cathode displayed reversible capacity of 1206.2 mA h g (1) at 0.1 C and capacity could be maintained at 691.7 mA h g (1) after more than 500 progressive cycles at a current density of 0.5 C. What's more, the BP2000-FeS-S cathode could output a capacity up to 659.2 mA h g (1) even at a current density of 2 C. This strategy can be widely extended to other kinds of metal sulfides or nitrides and probably be used widely. (C) 2017 Elsevier B.V. All rights reserved.