Proton-Coupled Smart Interphase Engineering Enabling Adaptive SEI Formation for Ultrastable Zinc Metal Anode

The instability of the zinc/electrolyte interphase remains a critical bottleneck for advancing aqueous zinc-ion batteries (AZIBs). Here, we demonstrate a shift from passive surface protection to active “smart” interphase regulation by introducing BIS-TRIS hydrochloride (BT) as a dynamic multifunctional electrolyte additive. Unlike conventional additives, BT enables a proton-coupled mechanism within the electric double layer that dynamically buffers interfacial pH fluctuations and directs the in situ formation of an adaptive solid–electrolyte interphase (SEI). The resulting SEI features a conductive inorganic inner layer and is continuously self-stabilized under operating conditions, ensuring robust interphase integrity. In situ Raman spectroscopy intuitively captures the establishment of a dynamic steady-state interphase microenvironment, which effectively suppresses H 2 O– and SO 4 2– -induced parasitic reactions. Benefiting from this intelligently regulated interphase, Zn||Zn cells exhibit an extended lifespan exceeding 2500 h at 5 mA cm –2 and 5 mAh cm –2 , while Zn//Cu cells deliver more than 3100 cycles with an average coulombic efficiency (CE) of 99.90% at 2 mA cm –2 and 0.5 mAh cm –2 . This work introduces proton-coupled intelligent interphase regulation as a promising strategy for enabling next-generation durable metal batteries.