Regulating lower hubbard band for tandem electrocatalytic lithium polysulfides conversion

Catalytic conversion of lithium polysulfides (LiPSs) is a promising avenue to suppress the shuttle effect and enhance the redox kinetics of lithium–sulfur (Li–S) batteries. However, the consecutive multiple LiPSs redox reactions make the activity prediction of electrocatalysts elusive. Herein, we propose a lower Hubbard band (LHB) descriptor to regulate tandem electrocatalytic LiPSs conversion for fast and robust Li–S batteries. Combined with theoretical calculations, the catalytic activity is jointly determined by the balance between LHB center position (Ɛ LHB ) and LHB width (Ꞷ LHB ). As a proof of concept, Fe 3 O 4 @FeP shows a balance of possessing a close Ɛ LHB to the Fermi level and a wide Ꞷ LHB simultaneously. An accelerated tandem electrocatalytic LiPSs conversion is achieved, where a close Ɛ LHB to Fermi level (with Fe 3 O 4 as the active center) benefits the adsorption of long-chain LiPSs and catalyzes S 8 -to-Li 2 S 4 process, while a wide Ꞷ LHB (with FeP as the active center) subsequently contributes to catalyze the Li 2 S 4 -to-Li 2 S reaction. Consequently, the elaborate Li–S batteries deliver outstanding cycle stability over 1000 cycles and superior rate performance over 10 C. Further, the constructed Ah-scale pouch cell delivers notable energy density of 360.6 Wh kg −1 . This work demonstrates the great promise of LHB regulation strategy for designing high-efficient electrocatalysts for Li–S batteries and beyond. • An electronic structure descriptor of lower Hubbard band (LHB) is proposed to realize tandem conversion of LiPSs. • The catalytic activity of electrocatalysts is determined by the LHB width (Ꞷ LHB ) and the LHB-band center position (Ɛ LHB ). • The rational designed Fe 3 O 4 @FeP shows a balance of possessing a close Ɛ LHB to the Fermi level and a wide Ꞷ LHB simultaneously. • The Li–S battery assembled with Fe 3 O 4 @FeP achieves excellent electrochemical performances and an Ah-scale pouch cell.