Electron Spin as a Descriptor for Sulfur Electrochemistry: Principles, Characterization, and Regulation Strategies in Sulfur-Based Batteries

• • Electron spin regulation offers a novel descriptor for sulfur electrocatalysis, addressing sluggish redox kinetics and polysulfide shuttling that limit sulfur-based batteries to below theoretical capacity (1675 mAh/g). • • Spectroscopic and magnetic characterization techniques (e.g., EPR, SQUID) enable direct probing of spin states, providing quantitative spin polarization data essential for rational catalyst design. • • Heteroatom doping, defect engineering, and coordination modulation can tune d-band spin splitting, enhancing d-p hybridization with sulfur species and improving interfacial charge transfer kinetics. • • Chirality-induced spin selectivity and external magnetic fields present non-invasive, scalable strategies to control spin polarization, potentially increasing sulfur utilization and cycle life in practical cells.