Polyphenol-Gated Composite Electrolytes with Enhanced Cross-Phase Lithium-Ion Transport for Solid-State Lithium Batteries

Highlights A biomimetic polyphenol-gated strategy is proposed to promote interfacial Li + - selective transport in composite solid electrolytes by chemically bonding the polymer matrix and ceramic nanofibers. The polyphenol interlayers serve as the chemical gates with –OH and –NH groups to immobilize lithium salt anions and carbonyl groups to coordinate Li + , thus lowering the energy barrier and promoting rapid Li + transport at interface. The assembled Li||LiFePO 4 batteries exhibits an impressive capacity of 151.6 mAh g −1 and long lifespan over 600 cycles. Abstract Solid-state lithium (Li) batteries offer high-energy density and operational safety but face sluggish Li + transport in polymer/ceramic composite solid-state electrolytes. Herein, we propose a bioinspired polyphenol-gated interfacial engineering that mimics ion-selective protein channels to enhance Li + -selective transport across the polymer–ceramic interface. Polyphenols such as polydopamine, poly-tannic acid, and poly-gallic acid chemically couple La 0.56 Li 0.33 TiO 3 ceramic nanofibers and glycidyl polyether matrix. Within this interface, carbonyl groups selectively coordinate Li⁺ and facilitate directional migration. On the other hand, hydroxyl and amino groups immobilize anions via hydrogen bonding. This chemical gating nearly doubles interfacial Li + concentration and boosts transference number to 0.68. The corresponding Li||LiFePO 4 battery exhibits stable cycling over 600 cycles with 85.5% capacity retention at 1 C, while the pouch cell delivers reliable operation under mechanical stress caused by bending and puncturing. This work demonstrates that polyphenol-gated interfaces are essential for promoting selective and efficient cross-phase Li⁺ transport for high-performance solid-state lithium-metal batteries.