Interface Reversible Electric Field Regulated by Amphoteric Charged Protein-Based Coating Toward High-Rate and Robust Zn Anode

Metallic interface engineering is a promising strategy to stabilize Zn anode via promoting Zn2+ uniform deposition. However, strong interactions between the coating and Zn2+ and sluggish transport of Zn2+ lead to high anodic polarization. Here, we present a bio-inspired silk fibroin (SF) coating with amphoteric charges to construct an interface reversible electric field, which manipulates the transfer kinetics of Zn2+ and reduces anodic polarization. The alternating positively and negatively charged surface as a build-in driving force can expedite and homogenize Zn2+ flux via the interplay between the charged coating and adsorbed ions, endowing the Zn-SF anode with low polarization voltage and stable plating/stripping. Experimental analyses with theoretical calculations suggest that SF can facilitate the desolvation of [Zn(H2O)(6)](2+) and provide nucleation sites for uniform deposition. Consequently, the Zn-SF anode delivers a high-rate performance with low voltage polarization (83 mV at 20 mA cm(-2)) and excellent stability (1500 h at 1 mA cm(-2); 500 h at 10 mA cm(-2)), realizing exceptional cumulative capacity of 2.5 Ah cm(-2). The full cell coupled with ZnxV2O5 center dot nH(2)O (ZnVO) cathode achieves specific energy of similar to 270.5/150.6 Wh kg(-1) (at 0.5/10 A g(-1)) with similar to 99.8% Coulombic efficiency and retains similar to 80.3% (at 5.0 A g(-1)) after 3000 cycles.

Automated summary

This study presents a bio-inspired silk fibroin (SF) coating to stabilize Zn anode via constructing an interface reversible electric field. The SF coating with amphoteric charges can manipulate the transfer kinetics of Zn2+ and reduce anodic polarization. Experimental and theoretical analyses demonstrate that the SF coating facilitates the desolvation of [Zn(H2O)6]2+ and provides nucleation sites for uniform deposition.