Self-Assembled Protein Nanofilm Regulating Uniform Zn Nucleation and Deposition Enabling Long-Life Zn Anodes.

Abstract

Rechargeable zinc-ion batteries (RZIBs) have gained promising attention as a feasible alternative for large-scale energy storage by the virtue of their intrinsic security, environmental benignity, low cost, and high volumetric capacity (5849mAhcm-3 ). Nevertheless, the deep-rooted issues of dendrite formation and side reactions in unstable Zn metal anode have impeded RZIBs from being dependably deployed in their proposed applications. Herein, silk fibroin (SF) and lysozyme (ly), as natural biomacromolecules with abundant polar groups arranged in polypeptide backbones, are in situ self-assembled on the Zn anode surface to construct a homogeneous and compact protein nanofilm. Such protein nanofilm protecting layer presents a negative charge surface and significantly regulates Zn2+ deposition behavior. Meanwhile, synergistic flexible and robust features of protein nanofilm function as artificial solid electrolyte interface (SEI), accommodates the dynamic volume deformation during deposition/dissolution, and blocks corrosion of side reactions. Consequently, the electrochemical stability of protein nanofilm-modified Zn anode is greatly improved, with an excellent extended lifespan of over 1100h at a high current density of 10mAcm-2 and a high cycling capacity of 10mAhcm-2 , corresponding to a high depth of discharge (83% DODZn ). Furthermore, the highly reversible Zn electrode remarkably improved the overall performance of MnO2 ||Zn full-cells.