Construction of spontaneous built-in electric field on heterointerface furnishing continuous efficient adsorption-directional migration-conversion of polysulfides.

Integrating sulfur with efficient electrocatalysts remains a pressing need in lithium-sulfur (Li-S) batteries for modulating the sluggish conversion kinetics and restricting the shuttle behavior of lithium polysulfides (LiPSs). Herein, a compact p-type FeO and n-type MoS heterostructure embedded on nitrogen-doped porous carbon (FeO-MoS-NPC-0.5) is meticulously constructed as dual-functional hosts that can facilitate continuous catalytic conversion of LiPSs. The p-type FeO exhibits a high affinity for polysulfides, while n-type MoS enables effective catalysis of LiPSs. The successful migration of LiPSs from FeO to MoS is bridged due to a spontaneous built-in electric field (BIEF) at the p-n heterojunction interface. The synergistic effect prevents the passivation of adsorption sites on FeO and enhances the efficient catalytic conversion capabilities of MoS. Consequently, the battery with FeO-MoS-NPC-0.5/S exhibits a prominent initial capacity of 1120.6 mAh g at 2 C, maintains outstanding cyclability with a capacity attenuation rate of 0.045 % per cycle at 0.5 C, and high sulfur utilization at large sulfur loadings. This work offers insights into optimizing the performance-enhanced Li-S battery electrodes by the formation of a dynamic "trapping-directional migration-conversion" reaction.