Journal Article

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

Lang, Xing-You, Chao, Danming, Huang, Houhou, Zhong, Mengxiao, Bai, Fu-Quan, Zhu, Meihua, Xie, Yunfei, Lu, Geyu, Ran, Qing, Jia, Xiaoteng

2022

Overview

HighlightsAlternating positively and negatively charged surface controlled by pH expedites and homogenizes Zn2+ flux, endowing the Zn- silk fibroin (SF) anode with low polarization voltage and stable stripping/plating.Experimental analyses with theoretical calculations suggest that SF coating facilitates the desolvation of [Zn(H2O)6]2+ and provides nucleation sites for uniform deposition.Symmetric battery of Zn–SF anodes delivers high-rate performance (up to 20 mA cm−2) and excellent stability (1500 h at 1 mA cm−2; 500 h at 10 mA cm−2) with cumulative capacity of 2.5 Ah cm−2.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·nH2O (ZnVO) cathode achieves specific energy of ~ 270.5/150.6 Wh kg−1 (at 0.5/10 A g−1) with ~ 99.8% Coulombic efficiency and retains ~ 80.3% (at 5.0 A g−1) after 3000 cycles.

• Publisher: Springer Nature B.V
• Subject: Amphoterics / Anodes / Anodic polarization / Coating / Deposition / Electric fields / Electrode polarization / Low voltage / Mathematical analysis / Nucleation / Plating / Silk fibroin / Specific energy / Stability