Cations Coordination‐Regulated Reversibility Enhancement for Aqueous Zn‐Ion Battery

Abstract

Aqueous Zn‐ion batteries are emerging as a promising candidate for large‐scale energy storage, while the short lifetime and poor reversibility of Zn anodes limit their further development. When attempting to enhance reversibility, most reported methods involve toxic and pollutive substances and decreased water content, which inevitably sacrificed safety level, rate performance, and environmentally benign characteristics. Herein, a series of low‐cost and “green” molecules are introduced into the aqueous (ZnCl2, ZnSO4) electrolytes, featured with cations coordination capability, which can significantly inhibit the hydration step of Zn2+ and delay the formation of the key by‐products (Zn5(OH)8Cl2·H2O, 3Zn(OH)3·ZnSO4·5H2O) in aqueous electrolytes via regulating the coordination status of Zn2+. In the optimized electrolyte system, a highly reversible Zn metal anode presents excellent electrochemical performance, featured with a long lifespan over 1185 h at 1 mA cm−2 and smooth deposition morphology. Furthermore, Zn–MnO2 batteries based on the electrolyte deliver high capacity retention of 82.9% after 200 cycles. These breakthroughs suggest that this method offers a versatile toolbox toward developing future advanced multivalent metal batteries for large‐scale energy storage.

Highly reversible zinc metal anodes enabled by protonated melamine

“…It should be pointed out that since the coordination capability of Mel is inferior to that of NH 3 that cannot coordinate with Zn 2+ in weak acid solutions, the formation of the Zn 2+ -Mel complex is impossible in ZnSO 4 electrolyte. 26,27 To illustrate the positive role of MelH + , Tafel curves of the Zn anode in Mel/ZnSO 4 and ZnSO 4 electrolytes are collected using a threeelectrode system (Fig. 1c).…”

In Situ Constructing Coordination Compounds Interphase to Stabilize Zn Metal Anode for High‐Performance Aqueous Zn–SeS2 Batteries

“…However, the large-scale application of AZMBs is still hindered by the unstable Zn anode and fast capacity fade, resulting from the uncontrollable dendrite growth and water-induced side reactions during repeated plating/stripping cycles. [5][6][7][8][9][10] To date, various strategies have been employed to solve above-mentioned challenges, such as artificial protective layer, 3D structural design, electrolyte engineering, and separators modification. [11,12] Among, modifying an artificial solid 1850 h (1.0 mA cm −2 , 1.0 mAh cm −2 ).…”

“…However, the large‐scale application of AZMBs is still hindered by the unstable Zn anode and fast capacity fade, resulting from the uncontrollable dendrite growth and water‐induced side reactions during repeated plating/stripping cycles. [ 5–10 ]…”

Interfacial Engineering Strategy for High-Performance Zn Metal Anodes

“…f 3D snapshot of the molecular dynamics simulation and solvation structure of Zn 2+ at 3–1 0.5 M TEHC. Copyright 2021 Wiley-VCH [ 110 ]. g Scheme depicting the proposed columnar structure formation of the deposited Zn on the substrate by Zn(OTf) 2 .…”

“…Recently, Yang et al . [ 110 ] proposed the introduction of a series of low-cost "green" molecules with a cation coordination ability into aqueous (ZnCl 2 and ZnSO 4 ) electrolytes. Triethylamine hydrochloride (TEHC) delivered the lowest binding energy of − 6.56 eV according to DFT simulations, indicating that the binding between TEHC and Zn 2+ was the most stable.…”