Dual-Functional Interfacial Layer Enabled by Gating-Shielding Effects for Ultra-Stable Zn Anode.

Large-scale application of low-cost, high-safety and environment-compatible aqueous Zn metal batteries (ZMBs) is hindered by Zn dendrite failure and side reactions. Herein, highly reversible ZMBs are obtained by addition of trace D-pantothenate calcium additives to engineer a dual-functional interfacial layer, which is enabled by a bioinspired gating effect for excluding competitive free water near Zn surface due to the trapping and immobilization of water by hydroxyl groups, and guiding target Zn transport across interface through carboxyl groups of pantothenate anions, as well as a dynamic electrostatic shielding effect around Zn protuberances from Ca cations to ensure uniform Zn deposition. In consequence, interfacial side reactions are perfectly inhibited owing to reduced water molecules reaching Zn surface, and the uniform and compact deposition of Zn is achieved due to promoted Zn transport and deposition kinetics. The ultra-stable symmetric cells with beyond 9000 h at 0.5 mA cm with 0.5 mAh cm and over 5000 h at 5 mA cm with 1 mAh cm, and an average Coulombic efficiency of 99.8% at 1 mA cm with 1 mAh cm, are amazingly realized. The regulated-electrolyte demonstrates high compatibility with verified cathodes for stable full cells. This work opens a brand-new pathway to regulate Zn/electrolyte interface to promise reversible ZMBs.