Atomically Dispersed Ni Site Catalysts Accelerating Sluggish Sulfur Redox Kinetics in Nonaqueous Zn‐S Batteries

ABSTRACT

Aqueous zinc‐ion batteries are hindered by parasitic water‐induced side reactions and a narrow electrochemical stability window. Transitioning to nonaqueous electrolytes offers a solution to these challenges, yet sluggish redox kinetics and poor sulfur conversion efficiency remain significant obstacles for practical Zn─S systems. Herein, we report a Ni single‐atom catalyst supported on Ketjen black (Ni‐SAC) as a high‐efficiency sulfur host for nonaqueous Zn─S batteries. By utilizing stable 1 

Zn(CF ₃ SO ₃ ) ₂ in acetonitrile electrolyte, we achieve highly reversible Zn plating/stripping with a Coulombic efficiency up to 99.9%. Consequently, the Ni‐SAC cathode delivers a high initial discharge capacity of 1068.4 mAh g ⁻¹ with improved long‐term stability over 400 cycles at 0.05 A g ⁻¹ , and 559.4 mAh g ⁻¹ over 150 cycles at 0.2 A g ⁻¹ . Notably, the cell achieves an areal capacity exceeding 4 mAh cm ⁻² under high sulfur loading up to 7.0 mg cm ⁻² . As validated by DFT calculations, Ni‐N ₄ active sites significantly lower activation energy barriers for rate‐limiting steps in the sulfur redox reaction. Furthermore, the efficacy of Ni‐SAC is demonstrated by operando wide‐angle X‐ray scattering analysis capturing reversible S ₈ /ZnS phase transformation and post‐mortem analysis revealing formation of robust ZnF ₂ ‐rich cathode‐electrolyte interphase. This study provides a strategy for bridging atomic‐scale catalysts with macroscopic performance in nonaqueous Zn─S chemistries.