Nonuniform ion flux triggers uneven lithium (Li) deposition and continuous dendrite growth, severely restricting the lifetime of Li-metal batteries (LMBs). Herein, an electronegative poly(pentafluorophenyl acrylate) (PPFPA) polymer brush-grafted Celgard separator signed as PPFPA-g-Celgard is designed to precisely construct one-dimensionally directed Li + flux at the nanoscale so as to realize faster ion transport and ultra-stable Li deposition. The grafting of PPFPA polymer chains is enabled by the simple bio-inspired engineering of surface-initiated atom transfer radical polymerization chemistry. Both theoretical and experimental analyses demonstrate an obvious increase by almost two times in Li + affinity and ion transfer kinetics for PPFPA-g-Celgard over the Celgard separator. Reversible and stable Li plating/stripping can be realized by rapidly switching from 0.5 to 6 mA cm -2 . Besides, the Li | PPFPAg-Celgard | LiFePO 4 full cell exhibits universal and long-term cyclability with a capacity retention of 83% over 700 cycles in ether electrolyte and 92.9% for over 300 cycles in carbonate electrolyte as well. This study represents a new direction for the general design of advanced separators with typical surface topochemistry and self-limited ion transport channels in the application of high-performance LMBs.

Polyether-based composite electrolytes exhibit great promises to bridge the gap between solid polymer electrolytes (SPEs) and high-energy solid-state Li metal batteries. However, the practical application is still hindered by the...

Lithium–sulfur (Li–S) batteries have attracted numerous attention owing to their overwhelming theoretical capacity. However, the dissolution and shuttle effect of lithium polysulfides (LiPSs) have seriously limited the development of Li–S batteries. Herein, we rationally designed a dual-engineered nanofibrous composite separator with a Janus structure to both physically and chemically block LiPS shuttling in Li–S batteries. The separator, consisting of a cross-linked poly­(vinyl alcohol)/poly­(acrylic acid) (CPP) composite nanofiber matrix and the electrosprayed poly­(vinyl alcohol) (PVA)/zeolitic imidazolate framework-8 (ZIF-8) layer on the cathode side, is fabricated through a facile electrospinning–electrospray coupling approach and signed as CPP@PVA/ZIF-8. The intrinsic narrow size and opened Lewis acid sites of ZIF-8 both confine free transport of LiPS anions. Meanwhile, the cross-linked CPP layer with abundant electronegative groups (−COOH) can shield the LiPS shuttle while ensuring the integrity of the flexible separator. Benefiting from the unique Janus structure, the CPP@PVA/ZIF-8 separator demonstrates a high initial capacity of 1125 mAh g–1 at a good coulombic efficiency of 98% over 300 cycles at 0.1 C. This work not only establishes a combined strategy to immobilize LiPSs but also provides novel interfacial engineering modification ideas for the development of high-performance separators in Li–S batteries.

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