Synchronous Dual Electrolyte Additive Sustains Zn Metal Anode with 5600 h Lifespan

Abstract

Despite conspicuous merits of Zn metal anodes, the commercialization is still handicapped by rampant dendrite formation and notorious side reaction. Manipulating the nucleation mode and deposition orientation of Zn is a key to rendering stabilized Zn anodes. Here, a dual electrolyte additive strategy is put forward via the direct cooperation of xylitol (XY) and graphene oxide (GO) species into typical zinc sulfate electrolyte. As verified by molecular dynamics simulations, the incorporated XY molecules could regulate the solvation structure of Zn2+, thus inhibiting hydrogen evolution and side reactions. The self‐assembled GO layer is in favor of facilitating the desolvation process to accelerate reaction kinetics. Progressive nucleation and orientational deposition can be realized under the synergistic modulation, enabling a dense and uniform Zn deposition. Consequently, symmetric cell based on dual additives harvests a highly reversible cycling of 5600 h at 1.0 mA cm−2/1.0 mAh cm−2.

Polycation‐Regulated Electrolyte and Interfacial Electric Fields for Stable Zinc Metal Batteries

“…Currently, most of the research on Zn anode focuses on macroscopic improvement of the reversibility and lifetime of Zn electrodes through electrolyte formulation with small molecule additives. It has been diffusely reported that the solvation structure of Zn 2+ can be easily changed through small molecule additives, such as methanol, glucose, saccharin, N‐methyl pyrrolidone, ethylene diamine tetraacetic acid, etc, and even the specific additives are decomposed to build a stable interphase or form an electrostatic shield layer to inhibit dendrite growth and side reactions [33–45] . Although these small molecule additives are effective in stabilizing the Zn anode, regulating the solvation sheath is ineluctably accompanied by low‐grade Zn 2+ deposition/dissolution kinetics, because of the strong intrinsic coupling between Zn 2+ and additive.…”

“…It has been diffusely reported that the solvation structure of Zn 2 + can be easily changed through small molecule additives, such as methanol, glucose, saccharin, N-methyl pyrrolidone, ethylene diamine tetraacetic acid, etc, and even the specific additives are decomposed to build a stable interphase or form an electrostatic shield layer to inhibit dendrite growth and side reactions. [33][34][35][36][37][38][39][40][41][42][43][44][45] Although these small molecule additives are effective in stabilizing the Zn anode, regulating the solvation sheath is ineluctably accompanied by lowgrade Zn 2 + deposition/dissolution kinetics, because of the strong intrinsic coupling between Zn 2 + and additive. Moreover, these additives cannot fundamentally restrain Zn anodes from contacting water owing to the inability to form a high-quality protective layer in a short time, and some may consume electrons from Zn anodes and be decomposed, which would result in a inferior CE and reversibility.…”

Hetero‐Polyionic Hydrogels Enable Dendrites‐Free Aqueous Zn‐I2 Batteries with Fast Kinetics

“…Some iodine hosts such as 2D MXenes, doped porous carbon materials, Prussian blue analogues, starch, and single atom catalysts were employed to construct efficient physical confinement and chemical adsorption for iodine species. [9][10][11][12][13][14][15][16][17][18] For Zn metal anode protection, effective approaches reported so far include surface coating layers (e.g., oxides, polymers, and metals), [19][20][21][22][23][24] optimized electrolytes (e.g., eutectic solution, water-in-salt, and gel-based electrolyte), [25][26][27][28][29][30][31][32][33][34] and threedimensional Zn hosts. [35] Apart from the dendrites prohibition, coating layers and separators could block the polyiodides shuttling via electrostatic repulsion effect or size limitation.…”

Fast Ionic Conducting Hydroxyapatite Solid Electrolyte Interphase Enables Ultra-Stable Zinc Metal Anodes

“…To conquer the aforementioned challenges, tremendous approaches have been proposed to improve the stability of the Zn anode, including anode structure design, , electrolyte optimization, − novel separators, , and interfacial modification. − Among these strategies, interfacial modification has been extensively researched due to its handleability and effectiveness in enhancing the performance of the Zn anode. A protective layer constructed on the Zn anode can physically isolate electrolyte; the side reactions and dendrite growth are extremely inhibited. , …”