Multiscale simulations of surface adsorption characteristics of amino acids on zinc metal anode

Abstract

Aqueous zinc-ion batteries (ZIBs) are considered promising power sources for grid storage, but they face several issues, including dendrite growth, corrosion, hydrogen evolution, etc., which are related to the Zn metal/liquid electrolyte interface. To address these challenges, many researchers have focused on modifying the Zn anode with surface adsorption. However, the underlying mechanism between the Zn surface and adsorbed/protective molecules has not been thoroughly explored. In this study, we built a multiscale simulation platform that integrates state-of-art simulation methods to comprehensively investigate the adsorption process of amino acids on the Zn metal surface. Our major finding is that adsorption sites, adsorbate–surface angle, and average distance are critical parameters for the stability and strength of surface adsorption. Additionally, ab initio molecular dynamics reveal the kinetics of the surface adsorption and molecule reorientation processes. Specifically, it can be discovered that the amino acids prefer to align parallel to the Zn metal surface, leading to better surface protection against corrosion and preventing dendrite growth. These findings pave the way for an in-depth understanding of the surface adsorption process, as well as providing concrete design principles for stable Zn metal anodes.