Unraveling the Volcano-Type Relationship in Polysulfides Adsorption-Catalysis over MoS ₂ for High-Performance Lithium–Sulfur Batteries

Molybdenum disulfide (MoS2) has shown great promise as a catalyst for lithium–sulfur (Li–S) batteries, yet the intrinsic relationship between polysulfide adsorption behavior and catalytic activity remains unclear, hindering rational catalyst design. Herein, we systematically modulate the electronic structure of MoS2 by introducing 3d transition metal cations and uncover a “volcano-type” correlation between adsorption strength and catalytic activity. Among the studied catalysts, Co-doped MoS2 exhibits moderate adsorption energy toward lithium polysulfides (LiPSs), which effectively reduces the energy barrier of sulfur redox reactions and facilitates rapid reaction kinetics. As a result, the Co-MoS2 cell delivers a high specific capacity of 626 mAh g–1 at 5.0C and maintains excellent cycling stability over 1200 cycles at 2.0C with a minimal decay rate of 0.041% per cycle. Combined electrochemical analysis and density functional theory (DFT) calculations reveal that optimal adsorption strength balances efficient LiPSs capture and facile product desorption. This work provides fundamental insights into the adsorption-catalysis interplay and offers a strategic principle for designing high-performance catalysts for Li–S batteries.