The partially filled d orbital of transition metal-based catalysts demonstrate excellent catalytic activity against polysulfides. However, an appropriate descriptor to reveal their structure-activity relationship is lacked. This study proposes a quantitative relationship between the eg occupancy of perovskite oxides and polysulfide catalytic activity, serving as an activity descriptor. LaCoO3, with a moderate eg occupation (t2g5eg1.08), demonstrates effective polysulfide anchoring and facilitated redox kinetics conversion compared to LaCrO3 (t2g3eg0) and LaFeO3 (t2g3eg2), showcasing exceptional catalytic performance. The degree of eg occupancy significantly influences the polysulfides adsorption strength, with empty or fully filled eg orbitals resulting in either strong or weak adsorption, respectively. LaCoO3-based batteries exhibit remarkable reversible capacity over 700 cycles at 1.0C, with a minimal capacity fading rate of 0.065 % per cycle. This work elucidates the crucial role of eg descriptor for evaluating the adsorption and conversion on polysulfides, offering insights into the development of innovative lithium-sulfur electrocatalysts.
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