High-Spin Sulfur-Mediated Phosphorous Activation Enables Safe and Fast Phosphorus Anodes for Sodium-Ion Batteries

Evaporation-condensation of red phosphorous to prepare phosphorous-based anodes inevitably generates white P residual, severely limiting its practical application due to the serious safety concern. Rather than removing the white P residual by complicated post-treatments, essentially prohibiting the generation of white P is a more meaningful alternative, but unfortunately it has been rarely studied so far. Herein, we demonstrate that the generation of white P can be substantially suppressed via sulfur-mediated phosphorous activation. Moreover, the prepared sulfur-doped P also exhibits the ever-reported fastest redox kinetics for sodium-ion storage. Electron spin resonance spectra and density functional theory calculations reveal that the introduced sulfur lives in the high-spin state during the evaporation-condensation process, which could activate P₄ for polymerization. Meanwhile, sulfur-induced electron delocalization can also accelerate the Na-P redox kinetics. The capability to modulate phosphorus polymerization via the high-spin mediator could revolutionize the application of phosphorous for batteries and beyond.