Non-Dendritic Zn Electrodeposition Enabled by Zincophilic Graphene Substrates

Abstract

Rechargeable zinc (Zn) batteries suffer from poor cycling performance that can be attributed to dendrite growth and surface-originated side reactions. Herein, we report that cycling performance of Zn metal anode can be improved significantly by utilizing monolayer graphene (Gr) as the electrodeposition substrate. Utilizing microscopy and X-ray diffraction techniques, we demonstrate that electrodeposited Zn on Gr substrate has a compact, uniform, and nondendritic character. The Gr layer, due to its high lattice compatibility with Zn, provides low nucleation overpotential sites for Zn electrodeposition. Atomistic calculations indicate that Gr has strong affinity to Zn (binding energy of 4.41 eV for Gr with four defect sites), leading to uniform distribution of Zinc adatoms all over the Gr surface. This synergistic compatibility between Gr and Zn promotes subsequent homogeneous and planar Zn deposits with low interfacial energy (0.212 J/m2) conformal with the current collector surface.

Controlling electrochemical growth of metallic zinc electrodes: Toward affordable rechargeable energy storage systems

“…3A). The origin of the energy release is manifold-(i) The possible binding between the metal deposit and a "metal-philic" substrate provides a chemical driving force (76), and (ii) the possible difference between surface tensions acts as a physical driving force. It has been argued in many studies that Mg metal does not form dendrites because of its "vanishing small" on January 10, 2021 http://advances.sciencemag.org/ Downloaded from surface diffusion barrier E diff that gives rise to a very large surface diffusivity D s (77).…”

“…This heteroepitaxy provides an effective manipulator for regulating the electrodeposition morphology of metals. We showed recently that horizontally aligned graphene layer, which has a  = 7% with Zn, can effectively promote the formation of horizontally aligned, (002)-textured Zn plate-like electrodeposits that claim plating/stripping efficiencies of >99.6% over thousands of cycles (22,76). In the early exploration of a group of powder-based Zn electrodes used in alkaline batteries (140), it has been suggested that the addition of some metal oxides (e.g., PbO or SnO) introduces a similar epitaxial effect (141).…”

Dendritic Zn Deposition in Zinc‐Metal Batteries and Mitigation Strategies

“…[ 64–68 ] Cu foil coated with monolayer graphene (Gr) via chemical vapor deposition (CVD) is shown as an effective approach to control crystal growth behavior of Zn. [ 69 ] As shown by SEM and X‐ray powder diffraction (XRD) analyses in Figure , the electrochemically platted Zn is grown in the (001) direction parallel to the Gr‐modified electrode surface. Density‐functional theory (DFT) calculations (Figure 11f‐j) show that Gr layer shows a high affinity toward Zn and can serve as a zincophilic substrate by absorbing Zn 2+ ions to the inherent defect sites of Gr.…”

Recent Advances of Emerging 2D MXene for Stable and Dendrite‐Free Metal Anodes

“…The modification strategies for Zn-metal anodes are similar to those of alkali-metal anodes. Up to now, a great deal of strategies have been proposed, such as constructing 3D current collectors, [121][122][123] providing a host for the "hostless" Zn anode, [124][125][126] modifying liquid electrolytes, [127][128][129] utilizing solid-state electrolytes, [130][131][132] alloy engineering, [133] using zincophilic substrates, [134] interfacial design, [135][136][137] adding seeds to regulate Zn deposition, [138] and designing multifunctional separators. [139]…”