High‐Performance Zinc–Bromine Rechargeable Batteries Enabled by In‐Situ Formed Solid Electrolyte Interphase

Aqueous zinc-bromine batteries (ZBBs) are promising candidates for renewable energy storage, offering advantages over lithium-ion batteries. However, their widespread adoption is hindered by challenges such as zinc dendrite formation and water decomposition, which lead to short circuits, electrode degradation and reduced cycle life. Therefore, this study presents a facile strategy for in-situ construction of a fluorinated solid electrolyte interphase (SEI) formed via coating graphite current collectors with a lubricant hydrophobic perfluoropolyether interlayer. During the initial charging process, a fluoride-rich SEI layer forms to regulate Zn nucleation and suppress dendrite growth. This SEI promotes uniform zinc deposition and inhibits hydrogen evolution by limiting water access to the electrode surface, thereby enhancing cycle life and energy efficiency. As a result, ZBBs incorporating this SEI exhibit a substantial reduction in potential hysteresis from 285 to 60 mV, deliver an energy density of nearly 20 Wh L^-1 and an areal capacity of 10.7 mAh cm^-2, and maintain >79% energy efficiency over 1000 cycles. This work offers a scalable approach to achieving high-performance ZBBs, advancing the development of next-generation anode-free zinc batteries.