Realizing Textured Zinc Metal Anodes through Regulating Electrodeposition Current for Aqueous Zinc Batteries

Abstract

Crystallography modulation of zinc (Zn) metal anode is promising to promote Zn reversibility in aqueous electrolytes, but efficiently constructing Zn with specific crystallographic texture remains challenging. Herein, we report a current‐controlled electrodeposition strategy to texture the Zn electrodeposits in conventional aqueous electrolytes. Using the electrolytic cell with low‐cost Zn(CH3COO)2 electrolyte and Cu substrate as a model system, the texture of as‐deposited Zn gradually transforms from (101) to (002) crystal plane as increasing the current density from 20 to 80 mA cm−2. Moreover, the high current accelerates the Zn nucleation rate with abundant nuclei, enabling uniform deposition. The (002) texture permits stronger resistance to dendrite growth and interfacial side reactions than the (101) texture. The resultant (002)‐textured Zn electrode achieves deep cycling stability and supports the stable operation of full batteries with conventional V/Mn‐based oxide cathodes.

Nonepitaxial Electrodeposition of (002)‐Textured Zn Anode on Textureless Substrates for Dendrite‐Free and Hydrogen Evolution‐Suppressed Zn Batteries

“…[ 55 ] Besides, some recent works discussed current density‐dependent texture development in Zn electrodeposits, whereas a comprehensive understanding of the fundamental mechanism is still missing. [ 19,24,56 ] Considering the HCP crystalline structure of Zn, the nucleus is assumed in uniform hexagonal platelet shape (Figure S8, Supporting information), and the varied Gibbs free energy (Δ G nucleation ) when forming a nucleus can be written as: $$\[\Delta {G_{{\rm{nucleation}}}} = - \frac{{3\sqrt 3 {R^2}h\rho nF}}{{2M}}\eta + 6Rh{\sigma _1} + \frac{{3\sqrt 3 {R^2}}}{2}\left( {{\sigma _1} + {\sigma _2} - {\sigma _3}} \right)\]$$where R is circumradius, h is the height of the platelet, ρ is density of Zn, n is the number of reaction electrons, F is Faraday's constant, η is overpotential, M is relative molecular mass of Zn, σ i ( i = 1, 2, 3) is interfacial energy between nuclei and solution, nuclei and substrate, solution and substrate, respectively. Then, the critical nucleus radius R c , calculated when $$\frac{{\partial \Delta G}}{{\partial R}} = 0$$, is written as follows: $$\[{R_{\rm{c}}} = \frac{{\frac{2}{{\sqrt 3 }}h{\sigma _1}}}{{\frac{{h\rho nF}}{M}\eta - \left( {{\sigma _1} + {\sigma _2} - {\sigma _3}} \right)}} = \frac{{\frac{2}{{\sqrt 3 }}C}}{{A\eta - B}}\]$$…”

“…d) 3D‐comparison of the plating–stripping performances (DOD, current density, and cumulative capacity) of our (002)‐Zn with some recent studies. [ 8,45,56,59–72 ] Respective details are listed in Table S1 (Supporting information) as well. e) XRD patterns of (002)‐Zn and Random‐Zn electrodes after specific plating–stripping cycles, and the corresponding SEM images of f–i) (002)‐Zn and j–m) Random‐Zn.…”

“…[55] Besides, some recent works discussed current densitydependent texture development in Zn electrodeposits, whereas a comprehensive understanding of the fundamental mechanism is still missing. [19,24,56] Considering the HCP crystalline structure of Zn, the nucleus is assumed in uniform hexagonal platelet shape (Figure S8, Supporting information), and the varied Gibbs free energy (ΔG nucleation ) when forming a nucleus can be written as:…”

“…Therefore, the suppressed hydrogen evolution of (002)-Zn can be ascribed to two reasons: 1) the (002) crystal plane is kinetically unfavorable for HER; 2) the low surface area due to the compact morphology; whereas, the mossy porous Random-Zn 002)-Zn with some recent studies. [8,45,56,[59][60][61][62][63][64][65][66][67][68][69][70][71][72] Respective details are listed in Table S1 (Supporting information) as well. e) XRD patterns of (002)-Zn and Random-Zn electrodes after specific plating-stripping cycles, and the corresponding SEM images of f-i) (002)-Zn and j-m) Random-Zn.…”

“…c) Rate performances at different current densities. d) 3D-comparison of the plating-stripping performances (DOD, current density, and cumulative capacity) of our (002)-Zn with some recent studies [8,45,56,[59][60][61][62][63][64][65][66][67][68][69][70][71][72]. Respective details are listed in TableS1(Supporting information) as well.…”