Revealing the Two‐Dimensional Surface Diffusion Mechanism for Zinc Dendrite Formation on Zinc Anode

Abstract

Aqueous zinc‐ion battery is regarded as one of the promising devices for large‐scale energy storage systems owing to its high safety, cost‐effectiveness, and competitive electrochemical properties. However, the dendrite growth on zinc metal anodes dramatically hinders its further practical applications, and the internal mechanism of dendrite evolution is still unclear. The introduction of a protective layer on the anode interface is an effective method to avoid zinc dendrite growth. Herein, a two‐dimensional (2D) atomic surface diffusion mechanism is proposed to reveal the evolution of zinc deposition from tiny protrusion to dendrite under uneven electric and ionic fields. Further, the conductive copper nitride (CN) protective layer is constructed on the zinc metal anode by a facile and scalable magnetron sputtering approach. Their protective layer possesses a high zinc affinity and high diffusion barrier for zinc atom migration, leading to spacious nucleation, and uniform zinc deposition, thus significantly boosting the electrochemical stability. For the first time, the role of the restricted 2D atomic surface diffusion mechanism in inhibiting the formation of zinc tiny protrusion that induces uneven electric and ionic fields is revealed. This work can provide a novel insight for future research on dendrite‐free zinc metal anodes by interfacial modification.

Atomically Dispersed Cu in Zeolitic Imidazolate Framework Nanoflake Array for Dendrite‐Free Zn Metal Anode

“…As shown by the migration structures (Figures 3f; Figure S16, Supporting Information) and the related energy profiles (Figures 3g), CuZIF-L exhibits a much higher Zn migration barrier (3.16 eV) between adjacent adsorption sites than the Zn (0.11 eV), which restricts Zn 2+ 2D atom diffusion on the surface. [24] Chronoamperograms in the symmetric cells tested at the overpotential of −150 mV also confirms the superiority of CuZIF-L over Zn with a faste formation of crystal nuclei (Figures 3h).…”

“…[13,14] To address these issues, numerous research efforts have been devoted to regulating the deposition behaviors via electrolyte optimization, [15][16][17] host design, [18][19][20] or interface engineering. [21][22][23][24] Especially, the utilization of 3D hosts has been considered as an effective method to alleviate the dendrite growth through the decrease of the local current density and the stabilization of Zn 2+ ion flux. [25][26][27] Moreover, the porous 3D hosts with enough space can accommodate the volumetric variation of Zn deposit.…”

“…[ 13,14 ] To address these issues, numerous research efforts have been devoted to regulating the deposition behaviors via electrolyte optimization, [ 15–17 ] host design, [ 18–20 ] or interface engineering. [ 21–24 ]…”

Effects of Adsorbate Diffusion and Edges in a Transition from Particle to Dendritic Morphology during Silver Electrodeposition

“…The modeling also advances in the quantitative description of the process, as we argue that the characteristic sizes of the deposited structures are set by the diffusion lengths of silver atoms and we use those lengths to estimate diffusion coefficients. For comparison, although several studies have already highlighted the importance of adsorbate relaxation in the initial stages of metal electrodeposition − and in the formation of dendritic films, − previous models − did not show the organized morphology of nanotrees or nanofeathers.…”

Nonionic Surfactant-Assisted In Situ Generation of Stable Passivation Protective Layer for Highly Stable Aqueous Zn Metal Anodes

“…Zn metal has attracted increasing interest as an anode for aqueous batteries owing to its high energy density (820 mAh/g and 5855 mAh/cm 3 ), low electrochemical potential (−0.762 V vs the standard hydrogen electrode (SHE)), material abundancy, and environmental friendliness. − However, Zn metal anodes meet a few challenging difficulties, including low reversibility, serious corrosion reactions, and rampant growth of dendrites; these limit their practical application. − The low reversibility and serious corrosion reactions result in a short lifespan of batteries, and the formation of Zn dendrites brings in a serious safety risk.…”