From Nano-Alloy to Nano-Laminated Interfaces for Highly Stable Alkali Metal Anodes.

Abstract

Metal anodes are considered as the holy grail for the next generation batteries because of their high gravimetric and volumetric specific capacity and low electrochemical potential. However, several unsolved challenges have impeded their practical applications, such as dendrite growth, interface side reaction, dead layer formation and volume change. An electrochemically, chemically, and mechanically stable artificial solid electrolyte interphase (SEI) is key to addressing the aforementioned issue with metal anodes. This study demonstrates a new concept of organic and inorganic hybrid interfaces for both Li and Na metal anodes. Through tailoring the compositions of the hybrid interfaces, we realize the nano-alloy structure to the nano-laminated structure. As a result, the nano-alloy interface (1Al2 O3 -1alucone or 2Al2 O3 -2alucone) presents the most stable electrochemical performances for both Li and Na metal anodes. The optimized thicknesses required for the nano-alloy interfaces for Li and Na metal anodes are different. A cohesive zone model was applied to interpret the underlying mechanism. Furthermore, the influence of the mechanical stabilities of the different interfaces on the electrochemical performances has been investigated experimentally and theoretically. Our approach provides a fundamental understanding and establishes the bridge between mechanical properties and electrochemical performance for alkali metal anodes. This article is protected by copyright. All rights reserved.