Crystal Plane Reconstruction and Thin Protective Coatings Formation for Superior Stable Zn Anodes Cycling 1300 h

Abstract

820 mAh g −1 ), which is attractive as the anode for aqueous batteries. [1] Based on these advantages, various zinc-metal batteries employing aqueous electrolyte with high safety (such as Zn-ion batteries, Zn-air batteries, and Zn-redox-flow batteries) have been intensively investigated. [2] Unfortunately, the poor chemical stability and electrochemical irreversibility of the Zn metal anode limit the practical applications of Zn rechargeable batteries. [3] Undesired side reactions and dendrite growth are two main challenges for aqueous Zn metal batteries.The nonuniform Zn 2+ flux of the interfacial layer on Zn can cause variations in the localized current density and ion depletion during cycling, thus resulting in large overpotentials and dendrite growth. [4] Continued dendrite growth can lead to penetration of the separator and cause short circuiting of cells. Moreover, nonuniform Zn plating/stripping may lead to further undesired side reactions between Zn and aqueous electrolytes. [5] To solve this problem, the interfacial coatings on the Zn surface are used to regulate Zn 2+ flux and suppress Zn dendrite growth, which finally avoids the well-known "tip effect." [6] In addition, the texture designs of the Zn metal surface play an important role in the orientation of the zinc crystal by plating. [7] Due to the smooth equipotential surface of Zn-(001) planes and the stronger adsorption energy of parallel direction between the (001) plane surface and Zn atom, the (001) crystal plane can guide plating sequentially parallel to it. [8] For example, Archer's group and Liang's group reported that the Zn foil exhibiting a preferred (001) texture by plastic deformation could suppress the rough plating/stripping landscape and promote uniform deposition along (001) planes. [9] Undesirable side reactions including chemical corrosion and hydrogen evolution mainly occurred at the interface between the Zn metal surface and electrolytes. [10] They would block the utilization of Zn, and then lead to electrolytes consumption and low Coulombic efficiency. [11] To solve this problem, various kinds of coatings have been made, which mainly include inorganic coating, polymer coating, organic, and inorganic composite coating. [12] They could block water molecules from reaching the Zn surface, and then improve the stability and reversibility of Zn metal anode. [13] However, thicker coatings were usually chosen to guarantee long-acting anticorrosion effect and retard the growth of dendrites, which meant the long route of ionic Some new insights into traditional metal pretreatment of anticorrosion for high stable Zn metal anodes are provided. A developed pretreatment methodology is employed to prefer the crystal plane of polycrystalline Zn and create 3.26 µm protective coatings mainly consisting of organic polymers and zinc salts on Zn foils (ROZ@Zn). In this process, Zn metal exhibits a surface-preferred (001) crystal plane proved by electron backscattered diffraction. Preferred (001) crystal planes and ROZ coatings can regulate ...

In Situ Growth of a Metal–Organic Framework-Based Solid Electrolyte Interphase for Highly Reversible Zn Anodes

“…Therefore, constructing an artificial SEI (ASEI) on the surface is a feasible approach to enhancing the stability of Zn metal anodes . A successfully designed ASEI can not only increase the kinetic overpotential for HER but also guide uniform Zn 2+ flux. , Moreover, a robust ASEI is highly desirable to restrain the dendrite growth of Zn …”

“…Apparently, the wettability of the Zn anode has been improved by the MOF ASEI, and the ZSB@Zn shows the smallest contact angle owing to the hydrophilic sulfonate groups. A small contact angle indicates good electrolyte–anode contact for charge transfer, and thus, better redox activity can be envisaged for the ZSB@Zn sample . Symmetric cells were assembled and tested to study the electrochemical performance of the anodes.…”

“…12 A successfully designed ASEI can not only increase the kinetic overpotential for HER but also guide uniform Zn 2+ flux. 13,14 Moreover, a robust ASEI is highly desirable to restrain the dendrite growth of Zn. 15 One routine strategy to introduce an ASEI is directly coating functional (in)organic materials on the surface of Zn.…”

“…A small contact angle indicates good electrolyte−anode contact for charge transfer, and thus, better redox activity can be envisaged for the ZSB@Zn sample. 14 Symmetric cells were assembled and tested to study the electrochemical performance of the anodes. Figure 2a shows the cyclic voltammetry (CV) curves of the symmetric cells.…”

Highly Stable Zn Anodes Modulated by Selenizing In Situ Grown Metal–Organic Frameworks

“…A smaller contact angle implies more uniform transport of Zn 2+ at the interface. 32,33 The contact angles of bare Zn, SCM@Zn, and CM@Zn reach 119.49°, 93.19°, and 101.80°, respectively (Figures 1j,k and S3). The good wettability of SCM@Zn could be attributed to the presence of CuSe decoration.…”