Discovering the Intrinsic Causes of Dendrite Formation in Zinc Metal Anodes: Lattice Defects and Residual Stress

Abstract

Developing a highly stable and dendrite-free zinc anode is essential to the commercial application of zinc metal batteries. However, the understanding of zinc dendrites formation mechanism is still insufficient. Herein, for the first time, we discover that the interfacial heterogeneous deposition induced by lattice defects and epitaxial growth limited by residual stress are intrinsic and critical causes for zinc dendrite formation. Therefore, an annealing reconstruction strategy was proposed to eliminate lattice defects and stresses in zinc crystals, which achieve dense epitaxial electrodeposition of zinc anode. The as-prepared annealed zinc anodes exhibit dendrite-free morphology and enhanced electrochemical cycling stability. This work first proves that lattice defects and residual stresses are also very important factors for epitaxial electrodeposition of zinc in addition to crystal orientation, which can provide a new mechanism for future researches on zinc anode modification.

A 3D-printed square-hole electrode for dendrite-free zinc–air batteries

“…In order to further investigate the potential of 3D Fe//Ni-Zn-X electrodes for commercial applications, the cycling stability of the cells was tested at different current densities (10,12,14,16,18, 20 mA cm −2 ). From Fig.…”

“…[4][5][6][7][8] The preferred zinc anode suffers from severe zinc dendritic growth and "dead Zn" 9 problems, which greatly restrict the practical application of zinc-air batteries. 10 During charging and discharging, uncontrolled dendrite growth may penetrate the separator and eventually connect the anode and cathode, leading to internal short circuits and cell failure. 11,12 The causes of zinc dendrites include inhomogeneous distribution of the electric field and ions, a high nucleation potential of zinc and irregular growth orientation at the electrode interface.…”

“…Zinc around these tips is provided with greater forces to nucleate, where this uneven nucleation results in the exacerbation of zinc dendrites. 10,[13][14][15] Meanwhile, some irregular zinc micro-spheres can also lead to uneven distribution of electric fields and ions, where partial nucleation could occur, and zinc dendrites and dead zinc appear consequently.…”

Engineering a Ni–Al Brucite-Based Interface Layer with Regulated Zn2+ Flux for Highly Reversible Zn Metal Anodes

“…11 Therefore, managing homogeneous Zn 2+ flux and engineering uniform nucleation sites are essential approaches to tackle the above issues. Several mitigative strategies have been implemented to enhance the electrochemical stability of the Zn anode by inhibiting Zn dendrite formation and eliminating interfacial side reactions, including electrolyte manipulation, 12,13 interfacial engineering, 14−16 substrates structural design, 17,18 etc. The available and implementable solution of employing a Zn anode interface layer has been considered promising in practical applications, including Ca 5 (PO 4 ) 3 (OH), 19 CaCO 3 , 20 TiO 2 , 21 ZrO 2 , 22 ZnS, 23 etc.…”