Boosting polysulfide conversion with a built–in electric field in Bi2S3@MnO2 heterostructure electrocatalysts

Lithium–sulfur (Li–S) batteries are hindered by sluggish lithium polysulfides (LiPSs) conversion kinetics and severe polysulfide shuttling, limiting their practical applications. To address these challenges, we designed a Bi 2 S 3 @MnO 2 CNFs composite via a two–step synthesis strategy, which synergistically enhances LiPSs adsorption and catalytic conversion. The built–in electric field (BIEF) at the Bi 2 S 3 /MnO 2 heterointerface drives the directional movement of LiPSs from the Bi 2 S 3 to the MnO 2 regions. This spatially restricted redox process effectively confines LiPSs within the carbon nanofibers (CNFs), suppressing their dissolution into the electrolyte and considerably reducing the shuttle effect. The Bi 2 S 3 @MnO 2 CNFs cathode delivers a high discharge capacity of 1569.7 mAh g −1 at 0.1 C, retaining 833.8 mAh g −1 at 3 C, and demonstrates remarkable cycling stability with 513.0 mAh g −1 after 1000 cycles (decay rate: 0.038 % per cycle). This study offers valuable insights for the design of high–performance Li–S battery materials.