ABSTRACT The liquid‐solid conversion of lithium polysulfides (LiPSs) to Li 2 S 2 /Li 2 S (Li 2 S x ⇄Li 2 S) impedes the sulfur reduction reaction (SRR) in lithium–sulfur (Li–S) batteries due to the slow kinetics and a high energy barrier. Herein, a heterostructure catalyst composed of Fe‐NC modified ZnCo 2 O 4 (Fe‐NC@ZnCo 2 O 4 ) is designed to accelerate LiPSs conversion (especially, Li 2 S 4 ⇄Li 2 S) via modulating the electron environment of the central atomic 3d‐orbital. Based on experimental results and DFT calculations, the introduction of Fe‐NC induces electron delocalization in the Co 3d orbital and eliminates the original bandgap of ZnCo 2 O 4 (1.98 eV). These delocalized electrons serve as electronic active centers, strengthening coupling between the metal 3d orbital and S n 2 − species in LiPSs and resulting in faster LiPSs redox kinetics. As a result, the S/Fe‐NC@ZnCo 2 O 4 cathode delivers a high capacity of 1449.7 mAh g − 1 at 0.1C and outstanding cycling stability with a decay rate of 0.057% per cycle over 600 cycles at 1.0C. Even under a high sulfur loading of 8.97 mg cm − 2 , a remarkable capacity of 917.5 mAh g − 1 is achieved. This work provides deep insights into orbital modulation for designing high‐performance Li–S catalysts.
Sun et al. (Sun,) studied this question.