Engineering Spatially Adjacent Sites with Synergistic Spin Polarization Effect to Promote Sulfur Redox Kinetics in...

The kinetics of sulfur catalytic reactions serve as a fundamental cornerstone for maximizing both the capacity and stability of lithium-sulfur batteries (LSBs). Recently, investigations into Li-S catalysts predominantly center around the optimization of energy levels to bolster adsorption and catalytic conversion processes. However, a significant oversight persists, as the profound influence of electron spin states on charge transfer dynamics and orbital interactions is frequently neglected. Herein, NH₄MnF₃ is synthesized as a sulfur host due to the strongly polarized Mn-F bonds, which generate a stronger ligand field and endow it with remarkable electrochemical activity. By capitalizing on the electric field-induced effect exerted by adjacent Co atoms, the crystal structure of NH₄MnF₃ is optimized, successfully inducing spin-orbit splitting at the Mn centers. This achievement significantly enhances the overlap with the p_z orbitals of polysulfides, effectively expediting the kinetic processes of sulfur redox reactions within LSBs. Notably, the Co-NH₄MnF₃ demonstrates exceptional electrochemical performance. Specifically, at a high rate of 2 C, it retains a remarkable specific capacity of 686 mAh g^-1 even after 1000 cycles. This work unveils the pivotal role played by the electron spin states of active centers in sulfur catalytic conversion.