Bi‐Functional Agarose‐Filled Porous Polysulfone Protective Layer for Dendrite‐Free Zn Anode

Abstract The uneven electric field and slow Zn ²⁺ desolvation lead to rapid dendrite growth during Zn plating and stripping, which severely deteriorates the performance of Zn metal anodes (ZMAs) in Zn‐ion batteries (ZIBs). Although polymer‐based artificial protective (PBAP) layers are widely applied to homogenize the electric field of ZMAs, they often fail to promote the desolvation process that eventually induces Zn dendrite growth. Herein, a bi‐functional protective layer, comprising a finger‐like porous matrix of polysulfone (PSF) and a hydroxyl‐rich filler of agarose (AG), is constructed to suppress Zn dendrite growth. COMSOL simulation demonstrates the ZMAs with bi‐functional protective layers (Zn@PSF/AG) exhibit uniform electric field and Zn ²⁺ distribution. Besides, the Zn@PSF/AG has both low desolvation energy and nucleation overpotential, effectively promoting the desolvation of Zn ²⁺ . Therefore, the Zn@PSF/AG symmetric cell exhibits excellent cycling performance, achieving 4200 h at 1 mA cm ⁻² /1 mAh cm ⁻² and 1000 h at 5 mA cm ⁻² /5 mAh cm ⁻² . When coupling with Zn _x V ₂ O ₅ (ZnVO) cathode, the ZnVO‖Zn@PSF/AG full cell shows similarly high cycling stability, maintaining 72% of its capacity after 7000 cycles at 10 A g ⁻¹ . This research highlights the positive roles of PBAP layer with multi‐functional matrix‐filler structure in developing long‐life ZIBs.