Zinc-based energy storage has lately gained popularity due to natural abundance, operational safety, high energy density. Unfortunately, dendrite growth is a common and intractable issue faced in existing zinc-ion batteries to shorten cycle lifespan/stability. This review summarizes recent progress in assembly component (e. g., anode, electrolyte, separator) engineering for dendrite-free zinc-ion batteries. First, diversiform strategies of Zn surface modification and Zn host design are presented to shield the fundamental adverse effect aroused by uneven zinc deposition on the anode. Then, subtle deployments of electrolyte constituents are illustrated to optimize the Zn2+ solvation structure for ultimate dendrite control and Coulombic efficiency elevation in aqueous systems and beyond (e.g., eutectic electrolytes). Furthermore, rational manipulation of advanced separators and the upgrade of zinc metal-free Zn2+-storage devices are briefly discussed to explore the dendrite-free and high-level Zn2+-storage. Finally, challenges and perspectives are proposed to offer research inspirations toward safe, high-efficiency and long-lifespan zinc storage.

Dendrite-Free Engineering toward Efficient Zinc Storage: Recent Progress and Future Perspectives.

The reversibility and cyclability of aqueous zinc-ion batteries (ZIBs) are largely determined by the stabilization of the Zn anode. Therefore, a stable anode/electrolyte interface capable of inhibiting dendrites and side reactions is crucial for high-performing ZIBs. In this study, we investigated the adsorption of 1,4-dioxane (DX) to promote the exposure of Zn (002) facets and prevent dendrite growth. DX appears to reside at the interface and suppress the detrimental side reactions. ZIBs with the addition of DX demonstrated a long-term cycling stability of 1000 h in harsh conditions of 10 mA cm-2 with an ultrahigh cumulative plated capacity of 5 Ah cm-2 and shows a good reversibility with an average Coulombic efficiency of 99.7%. The Zn//NH4V4O10 full battery with DX achieves a high specific capacity (202 mAh g-1 at 5 A g-1) and capacity retention (90.6% after 5000 cycles), much better than that of ZIBs with the pristine ZnSO4 electrolyte. By selectively adjusting the Zn2+ deposition rate on the crystal facets with adsorbed molecules, this work provides a promising modulation strategy at the molecular level for high-performing Zn anodes and can potentially be applied to other metal anodes suffering from instability and irreversibility.

Addition of Dioxane in Electrolyte Promotes (002)-Textured Zinc Growth and Suppressed Side Reactions in Zinc-Ion Batteries.

The most commonly used zinc foil anode for aqueous zinc‐ion batteries suffers from poor cycle stability and low zinc utilization. Zinc‐plated anodes on the host materials with high zincophilicity and stability are receiving increasing attention to alleviate these above issues. Here, the high zinc deposition activity of Cu (2 2 0) is confirmed through experimental observations and theoretical calculations and then Cu (2 2 0) substrates are prepared with the highly preferred orientation through an industrial electrolysis strategy. The prepared Cu (2 2 0) substrate can consistently modulate dense zinc growth by inducing the Zn (0 0 1) growth with the lowest surface energy and exposing high‐index zinc facets due to its exceptional grain size, high deposition activity, and homogeneous crystal orientation, which result in the high zinc plating/stripping reversibility of this Cu (2 2 0) substrate. When assembled into the Zn//MnO2 battery, the zinc‐plated Cu (2 2 0) can deliver capacity retention of 93.9% after 640 cycles at high zinc utilization (≈20%). This scalable orientation design strategy provides a new perspective for realizing dendrite‐free metal deposition with special textures.

High‐Index Zinc Facet Exposure Induced by Preferentially Orientated Substrate for Dendrite‐Free Zinc Anode

Ultrathin separators are indispensable to high‐energy‐density zinc‐ion batteries (ZIBs), but their easy failure caused by zinc dendrites poses a great challenge. Herein, 23 µm‐thick functional ultrathin separators (FUSs), realizing superb electrochemical stability of zinc anodes and outstanding long‐term durability of ultrathin separators, are reported. In the FUSs, an ultrathin but mechanically strong nanoporous membrane substrate benefits fast and flux‐homogenized Zn2+ transport, while a metal–organic framework (MOF)‐derived C/Cu nanocomposite decoration layer provides rich low‐barrier zinc nucleation sites, thereby synergistically stabilizing zinc anodes to inhibit zinc dendrites and dendrite‐caused separator failure. Investigation of the zinc affinity of the MOF‐derived C/Cu nanocomposites unravels the high zincophilicity of heteroatom‐containing C/Cu interfaces. Zinc anodes coupled with the FUSs present superior electrochemical stability, whose operation lifetime exceeds 2000 h at 1 mA cm−2 and 600 h at 10 mA cm−2, 40–50 times longer than that of the zinc anodes using glass‐fiber separators. The reliability of the FUSs in ZIBs and zinc‐ion hybrid supercapacitors is also validated. This work proposes a new strategy to stabilize zinc anodes and provides theoretical guidance in developing ultrathin separators for high‐energy‐density zinc‐based energy storage.

Functional Ultrathin Separators Proactively Stabilizing Zinc Anodes for Zinc‐Based Energy Storage

Realizing durative flattened and dendrite-free zinc (Zn) metal configuration is the key to resolving premature battery failure caused by the internal short circuit, which is highly determined by the crystal growth in the electrocrystallization process. Herein, we report that regulating the molecular structure of the inner Helmholtz plane (HIP) can effectively convert the deposition into activation control by weakening the solvated ion adsorption at the interface. The moderated electrochemical reaction kinetics lower than the adatom self-diffusion rate steers conformal stratiform Zn growth and dominant Zn (0001) texture, achieving crystallographic optimization. Through in-situ mediation of electrolyte engineering, orientational plating and stripping behaviors at edge-sites and tailored solvation structure immensely improve the utilization efficiency and total charge passed of Zn metal, even under extreme conditions, including high areal capacity (3 mAh cm-2) and wide temperature range (-40~60 °C).

Electrocrystallization Regulation Enabled Stacked Hexagonal Platelet Growth toward Highly Reversible Zinc Anodes.

Resource‐abundant metal (e.g., zinc) batteries feature intrinsic advantages of safety and sustainability. Their practical feasibility, however, is impeded by the poor reversibility of metal anodes, typically caused by the uncontrollable dendrite enlargement. Significant effort is exerted to completely prevent dendrites from forming, but this seems less effective at high current densities. Herein, this work presents an alternative dendrite regulation strategy of forming tiny, homogeneously distributed, and identical zinc dendrites by facet matching, which effectively avoids undesirable dendrite enlargement. Confirmed by multiscale theoretical screening and characterization, the regularly exposed Cu(111) facets at the ridges of a copper nanowire are capable of such dendrite regulation by forming a low‐mismatched Zn(002)/Cu(111) interface. Consequently, reversible zinc electroplating/stripping is achieved at an unprecedentedly high rate of 100 mA cm−2 for over 30 000 cycles, corresponding to an accumulative areal capacity up to 30 Ah cm−2. A full cell using this anode shows a high capacity of 308.3 mAh g−1 and a high capacity retention of 91.4% after 800 cycles. This strategy is also viable for magnesium and aluminum anodes, thus opening up a promising and universal avenue toward long‐life and high‐rate metal anodes.

An Ultrahigh Rate and Stable Zinc Anode by Facet‐Matching‐Induced Dendrite Regulation

Layered vanadium oxides are promising cathode materials for zinc-ion batteries (ZIBs) owing to their high capacity, but the sluggish electron/ion migration kinetics and structural collapse/dissolution severely limit their Zn2+-storage performance. Herein, poly(3,4-ethylenedioxythiophene) coated and Mn2+-intercalated vanadium oxides with rich oxygen vacancies ([email protected]) are prepared as the cathodes for ZIBs. The PEDOT coating, synergistic with oxygen vacancies, tailors the electron conductivity, and the Mn2+-intercalation enlarges the interlayer spacing for rapid Zn2+-ions diffusion. In addition, the pre-intercalated Mn2+-ions act as “pillars” to stabilize the structure, and the PEDOT coating prevents the direct contact of vanadium oxides with electrolyte to inhibit its dissolution during cycling. Thus, the [email protected] cathode exhibits superior discharge capacity, favorable rate capability (336.0 mAh g−1 at 8 A g−1), and satisfying cyclic durability (84.8% capacity retention over 2000 cycles). This work offers a facile and synergistic design strategy for achieving favorable cathodes for ZIBs. 

https://onlinelibrary.wiley.com/doi/pdfdirect/10.1002/eom2.12326

Conductive coating, cation‐intercalation, and oxygen vacancies co‐modified vanadium oxides as high‐rate and stable cathodes for aqueous zinc‐ion batteries

Aqueous zinc-ion batteries (ZIBs) have been regarded as a promising alternative to traditional lithium-based batteries due to their intrinsic advantages of safety, low cost, and abundance. However, the strong electrostatic interaction between Zn2+ and the layer-structured cathodes is still a key issue that hinders the batteries from storing more Zn. Herein, we report partially nitrided and cation-doped vanadium oxide for improved Zn storage performance. Specifically, the defects and nitride species that are generated inside the material upon nitriding improve the conductivity of the material and introduce a new Zn storage mechanism. The intercalation of cations, in contrast, widens the interlayer spacing to store more Zn2+ ions and enhances the cycling stability of the material. These merits synergistically lead to significantly enhanced electrochemical Zn2+ ion storage performance, in terms of a high specific capacity of 418.5 mAh·g−1 at a current density of 0.1 A·g−1 and a capacity retention of 81.2% after 500 cycles at 2.0 A·g−1. The new modification strategy for V2O5 suggested in this work could provide insight into the development of high-performance ZIBs.

/pdf/anion-and-cation-co-modified-vanadium-oxide-for-cathode-3unrh4s9.pdf

Shandong Tan

Papers

An Ultrahigh Rate and Stable Zinc Anode by Facet‐Matching‐Induced Dendrite Regulation

Conductive coating, cation‐intercalation, and oxygen vacancies co‐modified vanadium oxides as high‐rate and stable cathodes for aqueous zinc‐ion batteries

Anion and Cation Co-Modified Vanadium Oxide for Cathode Material of Aqueous Zinc-Ion Battery

Dual-modification of oxygen vacancies and PEDOT coating on MnO2 nanowires for high-performance zinc ion battery

Polyethylene Glycol Coating on Zinc Powder Surface: Applications in Dendrite-Free Zinc Anodes with Enhanced Utilization Rate