An aqueous electrolyte densified by perovskite SrTiO3 enabling high-voltage zinc-ion batteries

Simultaneous Manipulation of Anions and Water Molecules by Lewis Acid-Base for Highly Stable Zn Anodes

In aqueous zinc-ion batteries (ZIBs), Zn anodes often suffer from Zn dendrite and hydrogen evolution reaction (HER) in traditional electrolytes. Herein, fumed silica with both Lewis acid-base functional groups were introduced into traditional electrolytes. Owing to the strong Lewis acid-base interactions between Si─O─Si functional groups and SO4 2- ions, the Zn2+ ion transference number is significantly increased in electrolyte, and thus more Zn2+ ions reach the Zn anode surface. As a result, the distribution of Zn2+ ions will be more homogeneous and dendrites growth will be suppressed on the Zn anode surface. In addition, Si─OH functional groups on fumed silica can also constrain the free and solvated H2O molecules in electrolyte simultaneously through Lewis acid-base interactions between electronegative O atoms in Si─OH functional groups and electropositive H atoms in H2O molecules, ensuring that the HER is inhibited on Zn anodes. Therefore, in the fumed silica-contained electrolyte, the Zn anodes exhibit a high reversibility and Zn||MnO2 full batteries demonstrate a superior cycling performance.

Tailoring Zn-ion Solvation Structures for Enhanced Durability and Efficiency in Zinc-Bromine Flow Batteries

Aqueous zinc-bromine flow batteries (ZBFBs) are among the most appealing technologies for large-scale stationary energy storage due to their scalability, cost-effectiveness, safety and sustainability. However, their long-term durability is challenged by issues like the hydrogen evolution reaction (HER) and dendritic zinc electroplating. Herein, we address these challenges by reshaping the Zn2+ ion solvation structures in zinc bromide (ZnBr2) aqueous electrolytes using a robust hydrogen bond acceptor as a cosolvent additive. Our findings highlight the critical role of interactions within the first and second Zn2+ solvation shells in determining electrochemical performance. By selectively incorporating a low volume percentage of organic additive into the second coordination shell of Zn2+, we achieve effective proton capture, electrolyte pH stabilization during the Zn0 electroplating, and mitigation of ion transport resistance. This approach prevents the formation of a passivation interphase layer on the electrode surface, which typically occurs with higher additive concentrations, leading to increased interphase resistance and cell polarization. This work opens a new avenue in modulating Zn2+ reactivity and stability through precise solvation structure design, enabling efficient and reversible Zn0/2+ plating/stripping in aqueous electrolytes with suppressed H2 evolution. These findings pave the way for the development of commercially viable, high-performance ZBFBs for energy storage applications.

Suspension Electrolytes with Catalytically Self-Expediating Desolvation Kinetics for Low-Temperature Zinc Metal Batteries

The conventional electrolyte for rechargeable aqueous zinc metal batteries (AZMBs) breeds many problems such as Zn dendrite growth and side reaction of hydrogen evolution reaction, which are fundamentally attributed to the uneven ion flux owing to the high barriers of desolvation and diffusion of Zn[(H2O)6]2+ clusters. Herein, to modulate the [Zn(H2O)6]2+ solvation structure, the suspension electrolyte engineering employed with electron-delocalized catalytic nanoparticles is initially proposed to expedite desolvation kinetics. As a proof, the electron-density-adjustable CeO2- x is introduced into the commercial electrolyte and preferentially adsorbed on the Zn surface, regulating the Zn[(H2O)6]2+ structure. Meanwhile, the defect-rich CeO2- x redistributes the localized space electric field to uniformize ion flux kinetics and inhibits dendrite growth, as confirmed by a series of theoretical simulations, spectroscopical and experimental measurements. Encouragingly, the CeO2- x decorated suspension electrolyte enables a long stability over 1200 cycles at 5 mA cm-2 and an extended lifespan exceeding 6500 h with lower overpotentials of 34 mV under 0 °C. Matched with polyaniline cathodes, the full cells with suspension electrolyte exhibit a capacity-retention of 96.75% at 1 A g-1 under -20 °C as well as a long lifespan of up to 400 cycles in a large-areal pouch cell, showcasing promising potentials of suspension electrolyte for practical AZMBs.

Engineering Aqueous Electrolytes with Vicinal S-based Organic Additives for Highly Reversible Zinc-Ion Batteries

The commercial deployment of aqueous zinc-ion batteries (AZIBs) is hampered by dendrites, the hydrogen evolution reaction (HER), and corrosion reactions. To tackle these challenges, we have introduced 3,3'-dithiobis-1-propanesulfonic acid disodium salt (SPS), a symmetrical sulfur-based organic salt, as an electrolyte additive for AZIBs. Unlike conventional electrolyte additives that favor (002) deposition, SPS enables dense (100) growth through a unique symmetrically aligned concentration-controlled adsorption network, affording structural uniformity and compactness to the Zn deposit layer. The dual-action symmetrical SPS additive adsorbs onto the Zn surface via vicinal sulfur atoms, blocking electrolyte access to the Zn anode, enhancing the transportation kinetics of Zn2+, and simultaneously promoting desolvation by displacing water molecules from the solvation shell. This synergistic effect improves the stability of the Zn anode by mitigating HER and corrosion, resulting in over 1100 h of cycling at 5 mA cm-2, 5 mAh cm-2, stable operation at even 15 mA cm-2, 15 mAh cm-2, and achieving impressive Coulombic efficiency (CE) of 99.41%. As validation, the Zn/NaV3O8·1.35H2O cell with SPS-additive afforded high cycling stabilization and excellent capacity retention of 95.5%. This study offers valuable insights for advancing AZIBs and other metal-based batteries.

Turning Zn(PO3)2-Enriched Inorganic/Organic Hybrid Interfacial Chemistry with Chelating Ligands toward Robust Aqueous Zn Anodes

Due to the inherent redox potential of the zinc metal anode (ZMA), it is susceptible to corrosion and dendrite formation in aqueous electrolytes. These issues compromise the electroplating-stripping process at the electrolyte-electrode interface, adversely affecting the reversibility of aqueous zinc-ion batteries (AZIBs). Here, we propose a chelating-ligand additive (i.e., DS) strategy to construct in situ an inorganic/organic hybrid bilayer interface. The organic molecule enriched in -PO3 groups is calculated to preferentially adsorb onto the surface of ZMA. During subsequent reactions, these adsorbed molecules decompose preferentially due to their low lowest unoccupied molecular orbital energy level (0.34 eV), forming a Zn(PO3)2-enriched inorganic solid electrolyte interphase (SEI) layer. Simultaneously, the intermediate carbon skeleton cross-links, creating an organic layer atop the SEI, thereby forming an inorganic/organic hybrid SEI bilayer interface. This bilayer SEI interface effectively inhibits corrosion and hydrogen evolution reactions (HERs) while regulating the Zn2+ ion flux at the interface, inducing uniform Zn depositions. Consequently, the Zn||Zn symmetric battery demonstrates a long-term cycling lifespan exceeding 1700 h at 5 mA cm-2. The Zn||I2 pouch battery yielded a capacity retention of 71.3% after 1100 cycles. This synergistic modulation strategy offers insights into the development of ZMA stabilizer additives, potentially advancing the performance and durability of AZIBs.

Electrolyte Regulation toward Cathodes with Enhanced-Performance in Aqueous Zinc Ion Batteries

Enhancing cathodic performance is crucial for aqueous zinc-ion batteries, with the primary focus of research efforts being the regulation of the intrinsic material structure. Electrolyte regulation is also widely used to improve full-cell performance, whose main optimization mechanisms have been extensively discussed only in regard to the metallic anode. Considering that ionic transport begins in the electrolyte, the modulation of the electrolyte must influence the cathodic performance or even the reaction mechanism. Despite its importance, the discussion of the optimization effects of electrolyte regulation on the cathode has not garnered the attention it deserves. To fill this gap and raise awareness of the importance of electrolyte regulation on cathodic reaction mechanisms, this review comprehensively combs the underlying mechanisms of the electrolyte regulation strategies and classifies the regulation mechanisms into three main categories according to their commonalities for the first time, which are ion effect, solvating effect, and interfacial modulation effect, revealing the missing puzzle piece of the mechanisms of electrolyte regulation in optimizing the cathode.

Elimination of Concentration Polarization Under Ultra-High Current Density Zinc Deposition by Nanofluid Self-Driven Ion Enrichment

The commercialization of zinc metal batteries aims at high-rate capability and lightweight, which requires zinc anodes working at high current density, high areal capacity, and high depth of discharge. However, frequent zinc anode fades drastically under extreme conditions. Herein, it is revealed that the primary reason for the anode instability is the severe concentration polarization caused by the imbalanced consumption rate and transfer rate of Zn2+ under extreme conditions. Based on this finding, a nanofluid layer is constructed to rapidly absorb Zn2+ and mitigate the polarization induced by the nonlinear transport of interfacial ions. The modified zinc anode sustains at extreme conditions for over 1573 h (40 mA cm-2, 40 mAh cm-2, DOD = 75.97%) and 490 h (100 mA cm-2, 100 mAh cm-2, DOD = 90.91%), and achieving an unprecedented cumulative capacity of 62.92 Ah cm-2. This work offers both fundamental and practical insights for the interface design in energy storage devices.

High-Entropy Electrolytes with High Disordered Solvation Structures for Ultra-Stable Zinc Metal Anodes

Aqueous zinc-ion batteries (ZIBs) are playing an increasingly important role in the field of energy storage owing to their low cost, high safety, and environmental friendliness. However, their practical applications are still handicapped by severe dendrite formation and side reactions (e.g., hydrogen evolution reaction and corrosion) on the zinc anodes. Herein, a low-concentration high-entropy (HE) electrolyte strategy is proposed to achieve high reversibility and ultra-durable zinc metal anode. Specifically, this HE electrolyte features multiple anions participating in coordination and highly disordered solvation shells, which would disrupt the intrinsic H-bond network between water molecules and suppress interfacial side reactions. Moreover, these diversified weakly solvated structures can lower the solvation energy of Zn2+ solvation configurations and enhance zinc ion diffusion kinetics, thereby promoting uniform Zn deposition and electrode interface stability. Consequently, Zn||Zn symmetric cells exhibit over 2,000 hours of cycling stability, and Zn||Cu asymmetric cells achieve a high average Coulombic efficiency of 99.9 % over 500 cycles. Furthermore, the Zn||PANI full cell with the optimized HE-50 mM electrolyte delivers a high specific capacity of 110.7 mAh g-1 over 2,000 cycles at 0.5 A g-1 and a capacity retention of 70.4 % at 15 A g-1 after 10,000 cycles. Remarkably, even at a low temperature of -20 °C, the Zn||PANI full cells equipped with HE-50 mM electrolyte still demonstrate long-term cycling stability over 600 cycles with a high-capacity retention of 93.5 %. This research provides a promising strategy for the design of aqueous electrolytes, aiding in the development of low-cost, high-safety, and high-performance aqueous batteries.

In-situ positive electrode-electrolyte interphase construction enables stable Ah-level Zn-MnO2 batteries

Engineering the formulation of an Mn-based positive electrode is a viable strategy for producing an efficient aqueous zinc-ion battery. However, Mn dissolution and the byproducts result in capacity fading, thus limiting its electrochemical performances. To solve the undesirable issues, the concept of in-situ forming the positive electrode/electrolyte interface on the commercial MnO2 is designed, with the help of introducing the Dioctyl Phthalate into the ZS-based electrolyte (2 M ZnSO4 + 0.2 M MnSO4), designated as ZS-DOP electrolyte. An advanced three-dimensional chemical and imaging analysis on a model material reveals the dynamic formation of positive electrode/electrolyte interface. The formed organic interface effectively suppresses the corrosion of the electrolytes with its hydrophobicity, and adjusts the pH value according to Le Chatelier's Principle to inhibit the production of by-products. Specifically, the pouch cell assembled with the ZS-DOP electrolyte attains a reversible capacity of ~2.5 Ah and powers the unmanned aerial vehicle. Furthermore, photovoltaic energy storage applications deliver a stable capacity of 0.5 Ah and realize the power supply for mobile phones and other electronic devices. Our results facilitate the development of in-situ surface protection on the positive electrode in aqueous zinc-ion battery, providing insights into its practical application.

Reviving Zn Dendrites to Electroactive Zn2+ by Ion Sieve Interface

Zn0 dendrite formation during repeated plating/stripping processes limits the practical use of Zn-metal anodes in reliable and affordable energy storage. Traditional methods, including dendrite suppression and dendrite regulation, fail under demanding performance conditions due to Zn2+ diffusion limitations and concentration gradients. Here, using an in situ pre-zincation approach, a Li2ZnxTi3-xO8 (LZTO, 0 Collapse

Key Words

• Zn anode
• Zn2+ ion sieve
• dendrite‐free
• interface engineering

Collapse

MESH Headings Collapse

Grants

• 52162036 National Natural Science Foundation of China
• 22378342 National Natural Science Foundation of China
• 2021D01D08 Nature Science Foundation of Xinjiang Province
• 2022A01005-4 Xinjiang Autonomous Region Major Projects
• 2021A01001-1 Xinjiang Autonomous Region Major Projects
• No. 202006750014 China Scholarship Council
• FL210100050 Australian Research Council
• DE240100159 Australian Research Council

Collapse

Affiliation(s)

Zhenjie Liu State Key Laboratory of Chemistry and Utilization of Carbon Based Energy Resources, College of Chemistry, Xinjiang University, Urumqi, Xinjiang, 830017, China
Murong Xi State Key Laboratory of Chemistry and Utilization of Carbon Based Energy Resources, College of Chemistry, Xinjiang University, Urumqi, Xinjiang, 830017, China
Guanjie Li School of Chemical Engineering, The University of Adelaide, Engineering North, North Terrace Campus, The University of Adelaide, Adelaide, South Australia, 5069, Australia
Yudai Huang State Key Laboratory of Chemistry and Utilization of Carbon Based Energy Resources, College of Chemistry, Xinjiang University, Urumqi, Xinjiang, 830017, China
Lei Mao School of Chemical Engineering, The University of Adelaide, Engineering North, North Terrace Campus, The University of Adelaide, Adelaide, South Australia, 5069, Australia
Jun Xu School of Chemical Engineering, The University of Adelaide, Engineering North, North Terrace Campus, The University of Adelaide, Adelaide, South Australia, 5069, Australia
Wei Wang State Key Laboratory of Chemistry and Utilization of Carbon Based Energy Resources, College of Chemistry, Xinjiang University, Urumqi, Xinjiang, 830017, China
Zihan Qi State Key Laboratory of Chemistry and Utilization of Carbon Based Energy Resources, College of Chemistry, Xinjiang University, Urumqi, Xinjiang, 830017, China
Juan Ding State Key Laboratory of Chemistry and Utilization of Carbon Based Energy Resources, College of Chemistry, Xinjiang University, Urumqi, Xinjiang, 830017, China
Shilin Zhang School of Chemical Engineering, The University of Adelaide, Engineering North, North Terrace Campus, The University of Adelaide, Adelaide, South Australia, 5069, Australia
Zaiping Guo School of Chemical Engineering, The University of Adelaide, Engineering North, North Terrace Campus, The University of Adelaide, Adelaide, South Australia, 5069, Australia

Collapse

Collaborators Collapse

Transforming Detrimental Crystalline Zinc Hydroxide Sulfate to Homogeneous Fluorinated Amorphous Solid-Electrolyte Interphase on Zinc Anode

The formation of non-ion conducting byproducts on zinc anode is notoriously detrimental to aqueous zinc-ion batteries (AZIBs). Herein, we successfully transform a representative detrimental byproduct, crystalline zinc hydroxide sulfate (ZHS) to fast-ion conducting solid-electrolyte interphase (SEI) via amorphization and fluorination induced by suspending CaF2 nanoparticles in dilute sulfate electrolytes. Distinct from widely reported nonhomogeneous organic-inorganic hybrid SEIs that exhibit structural and chemical instability, the designed single-phase SEI is homogeneous, mechanically robust, and chemically stable. These characteristics of the SEI facilitate the prevention of zinc dendrite growth and reduction of capacity loss during long-term cycling. Importantly, AZIB full cells based on this SEI-forming electrolyte exhibit exceptional stability over 20,000 cycles at 3 A/g with a charging voltage of 2.2 V without short circuits and electrolyte dry-out. This work suggests avenues for designing SEIs on a metal anode and provides insights into associated SEI chemistry.

Design of asymmetric electrolytes for aqueous zinc batteries

Aqueous Zn batteries are gaining increasing research attention in the energy storage area due to their intrinsic safety, potentially low cost and environmental friendliness; however, the zinc dendrite formation, zinc corrosion, passivation and the hydrogen evolution reaction induced by water at the anode side, and materials dissolution as well as intrinsic poor reaction kinetics at cathode side in aqueous systems, seriously shorten the cycling life and decrease energy density of batteries and greatly hinder their development. Recent advancements in asymmetric electrolytes with various functions are promising to overcome such challenges for zinc batteries at the same time. It has been proved that the applications of asymmetric electrolytes show significant contributions in the field of zinc-based batteries in suppressing side reactions while maintaining electrochemical performance to satisfy both anode and cathode. Therefore, this perspective summarizes recent advancements in asymmetric electrolytes' design and applications for zinc batteries and outlines opportunities and future challenges, expecting continued research attention in this area.

A tellurium iodide perovskite structure enabling eleven-electron transfer in zinc ion batteries

The growing potential of low-dimensional metal-halide perovskites as conversion-type cathode materials is limited by electrochemically inert B-site cations, diminishing the battery capacity and energy density. Here, we design a benzyltriethylammonium tellurium iodide perovskite, (BzTEA)2TeI6, as the cathode material, enabling X- and B-site elements with highly reversible chalcogen- and halogen-related redox reactions, respectively. The engineered perovskite can confine active elements, alleviate the shuttle effect and promote the transfer of Cl- on its surface. This allows for the utilization of inert high-valent tellurium cations, eventually realizing a special eleven-electron transfer mode (Te6+/Te4+/Te2-, I+/I0/I-, and Cl0/Cl-) in suitable electrolytes. The Zn||(BzTEA)2TeI6 battery exhibited a high capacity of up to 473 mAh g-1Te/I and a large energy density of 577 Wh kg-1 Te/I at 0.5 A g-1, with capacity retention up to 82% after 500 cycles at 3 A g-1. The work sheds light on the design of high-energy batteries utilizing chalcogen-halide perovskite cathodes.

Engineering of Charge Density at the Anode/Electrolyte Interface for Long-Life Zn Anode in Aqueous Zinc Ion Battery

The aqueous zinc ion battery emerges as the promising candidate applied in large-scale energy storage system. However, Zn anode suffers from the issues including Zn dendrite, Hydrogen evolution reaction and corrosion. These challenges are primarily derived from the instability of anode/electrolyte interface, which is associated with the interfacial charge density distribution. In this context, the recent advancements concentrating on the strategies and mechanisms to regulate charge density at the Zn anode/electrolyte interface are summarized. Different characterization techniques for charge density distribution have been analysed, which can be applied to assess the interfacial zinc ion transport. Additionally, the charge density regulations at the Zn anode/electrolyte interface are discussed, elucidating their roles in modulating electrostatic interactions, electric field, structure of solvated zinc ion and electric double layer, respectively. Finally, the perspectives and challenges on the further research are provided to establish the stable anode/electrolyte interface by focusing on charge density modifications, which is expected to facilitate the development of aqueous zinc ion battery.

Unraveling Energy Storage Performance and Mechanism of Metal-Organic Framework-Derived Copper Vanadium Oxides with Tunable Composition for Aqueous Zinc-Ion Batteries

Achieving high-performance aqueous zinc (Zn)-ion batteries (AZIBs) requires stable and efficient cathode materials capable of reversible Zn-ion intercalation. Although layered vanadium oxides possess high Zn-ion storage capacity, their sluggish kinetics and poor conductivity present significant hurdles for further enhancing the performance of AZIBs. In response to this challenge, a dissolution-regrowth and conversion approach is formulated using metal-organic frameworks (MOFs) as a sacrificial template, which enables the in situ creation of copper vanadium oxides (CuVOx) with porous 1D channels and distinctive nanoarchitectures. Owing to their distinctive structure, the optimized CuVOx cathode experiences a reaction involving the synergistic insertion/extraction of Zn2+, resulting in rapid Zn2+ diffusion kinetics and enhanced electrochemical activity postactivation. Specifically, the activated electrode delivers a reversible capacity of 519 mAh g-1 at 0.5 A g-1 for AZIBs. It is noteworthy that the electrode exhibits a remarkable reversible rate capacity of 220 mAh g-1 at 5 A g-1 with excellent durable cycleability, retaining 88% of its capacity even after 3000 cycles. Various ex situ testing methods endorse the reversible insertion/extraction of Zn2+ in the CuVOx cathode. This study provides a novel insight into high-performance MOF-derived unique structure designs for AZIB electrodes.

Iron-Free Anode Boosting High Energy Efficiency Aqueous Full Iron-Ion Batteries

Aqueous iron-ion batteries with reversible storage of Fe2+ have undergone rapid development in recent years. Consistently throughout these studies, metallic iron is selected as the anode material. However, the large overpotential (250 mV) associated with the plating/stripping process of iron in aqueous solutions leads to unsatisfactory energy efficiency of the battery, although high capacity and Coulomb efficiency can be achieved. Herein, an iron-free anode material, 9,10-anthraquinone (AQ) is proposed in aqueous iron-ion batteries, which shows a low reaction potential and minimal polarization during storing iron ions. The organic anode exhibits favorable specific capacity of 106 mAh g-1 at 0.5 A g-1 and excellent cycling stability (92.6% retention after 500 cycles). In addition, an aqueous full iron-ion battery is constructed using AQ as the anode and 9,10-phenanthraquinone (PQ) as the cathode. The full battery demonstrates an enhanced energy efficiency of 72%, which is 206% higher than that of metal iron anode, and shows excellent cycling stability and Coulombic efficiency. This work provides a viable route to overcome the high polarization of metallic iron anode and promote the development of aqueous iron-ion batteries.

A liquid-infiltrated Al2O3 framework electrolyte enables aqueous zinc batteries

Aqueous zinc-ion battery anodes face the twin challenges of dendrite growth and severe side reactions. Here a liquid-infiltrated Al2O3 framework electrolyte (LIAFE) is developed to address these issues and enables stable long-life Zn anodes for over 4000 hours. The LIAFE shows a uniform morphology and exhibits enhanced performance.

An Ion-Pumping Quasi-Solid Electrolyte Enabled by Electrokinetic Effects for Stable Aqueous Zinc Metal Batteries

The practical application of aqueous zinc (Zn) metal batteries (ZMBs) is hindered by the complicated hydrogen evolution, passivation reactions, and dendrite growth of Zn metal anodes. Here, an ion-pumping quasi-solid electrolyte (IPQSE) with high Zn2+ transport kinetics enabled by the electrokinetic phenomena to realize high-performance quasi-solid state Zn metal batteries (QSSZMBs) is reported. The IPQSE is prepared through the in situ ring-opening polymerization of tetramethylolmethane-tri-β-aziridinylpropionate in the aqueous electrolyte. The porous polymer framework with high zeta potential provides the IPQSE with an electrokinetic ion-pumping feature enabled by the electrokinetic effects (electro-osmosis and electrokinetic surface conduction), which significantly accelerates the Zn2+ transport, reduces the concentration polarization and overcomes the diffusion-limited current. Moreover, the Zn2+ affinity of the polymer and hydrogen bonding interactions in the IPQSE changes the Zn2+ coordination environment and reduces the amount of free H2O, which lowers the H2O activity and inhibits H2O-induced side reactions. Consequently, the highly reversible and stable Zn metal anodes are achieved. The assembled QSSZMBs based on the IPQSE display excellent cycling stability with high capacity retention and Coulombic efficiency. The high-performance quasi-solid state Zn metal pouch cells are demonstrated, showing great promise for the practical application of the IPQSE.

Atomic Level-Macroscopic Structure-Activity of Inhomogeneous Localized Aggregates Enabled Ultra-Low Temperature Hybrid Aqueous Batteries

The utilization of hybrid aqueous electrolytes has significantly broadened the electrochemical and temperature ranges of aqueous batteries, such as aqueous zinc and lithium-ion batteries, but the design principles for extreme operating conditions remain poorly understood. Here, we systematically unveil the ternary interaction involving salt-water-organic co-solvents and its intricate impacts on both the atomic-level and macroscopic structural features of the hybrid electrolytes. This highlights a distinct category of micelle-like structure electrolytes featuring organic-enriched phases and nanosized aqueous electrolyte aggregates, enabled by appropriate low donor number co-solvents and amphiphilic anions. Remarkably, the electrolyte enables exceptional high solubility, accommodating up to 29.8 m zinc triflate within aqueous micelles. This configuration maintains an intra-micellar salt-in-water setup, allowing for a broad electrochemical window (up to 3.86 V), low viscosity, and state-of-the-art ultralow-temperature zinc ion conductivity (1.58 mS cm-1 at -80 °C). Building upon the unique nature of the inhomogeneous localized aggregates, this micelle-like electrolyte facilitates dendrite-free Zn plating/stripping, even at -80 °C. The assembled Zn||PANI battery showcases an impressive capacity of 71.8 mAh g-1 and an extended lifespan of over 3000 cycles at -80 °C. This study opens up a promising approach in electrolyte design that transcends conventional local atomic solvation structures, broadening the water-in-salt electrolyte concept.

In Situ Constructing Metal-Organic Complex Interface Layer Using Biomolecule Enabling Stabilize Zn Anode

Aqueous zinc-ion batteries (ZIBs) are considered as a promising candidate for next-generation large-scale energy storage due to their high safety, low cost, and eco-friendliness. Unfortunately, commercialization of ZIBs is severely hindered owing to rampant dendrite growth and detrimental side reactions on the Zn anode. Herein, inspired by the metal-organic complex interphase strategy, the authors apply adenosine triphosphate (ATP) to in situ construct a multifunctional film on the metal Zn surface (marked as ATP@Zn) by a facile etching method. The ATP-induced interfacial layer enhances lipophilicity, promoting uniform Zn2+ flux and further homogenizing Zn deposition. Meanwhile, the functional interlayer improves the anticorrosion ability of the Zn anode, effectively suppressing corrosion and hydrogen evolution. Consequently, the as-prepared ATP@Zn anode in the symmetric cell exhibits eminent plating/stripping reversibility for over 2800 h at 5.0 mA cm-2 and 1 mAh cm-2. Furthermore, the assembled ATP@Zn||MnO2 full cells are investigated to evaluate practical feasibilities. This work provides an efficient and simple strategy to prepare stabilized Zn anode toward high-performance ZIBs.

A Cu/MnOx Composite with Copper-Doping-Induced Oxygen Vacancies as a Cathode for Aqueous Zinc-Ion Batteries

Aqueous zinc-ion batteries are anticipated to be the next generation of important energy storage devices to replace lithium-ion batteries due to the ongoing use of lithium resources and the safety hazards associated with organic electrolytes in lithium-ion batteries. Manganese-based compounds, including MnOx materials, have prominent places among the many zinc-ion battery cathode materials. Additionally, Cu doping can cause the creation of an oxygen vacancy, which increases the material's internal electric field and enhances cycle stability. MnOx also has great cyclic stability and promotes ion transport. At a current density of 0.2 A g-1, the Cu/MnOx nanocomposite obtained a high specific capacitance of 304.4 mAh g-1. In addition, Cu/MnOx nanocomposites showed A high specific capacity of 198.9 mAh g-1 after 1000 cycles at a current density of 0.5 A g-1. Therefore, Cu/MnOx nanocomposites are expected to be a strong contender for the next generation of zinc-ion battery cathode materials in high energy density storage systems.

Industrial Waste Derived Separators for Zn-Ion Batteries Achieve Homogeneous Zn(002) Deposition Through Low Chemical Affinity Effects

Designing a cost-effective and multifunctional separator that ensures dendrite-free and stable Zn metal anode remains a significant challenge. Herein, a multifunctional cellulose-based separator is presented consisting of industrial waste-fly ash particles and cellulose nanofiber using a facile solution-coating method. The resulting fly ash-cellulose (FACNF) separators enable a high ion conductivity (5.76 mS cm-1) and low desolvation energy barrier of hydrated Zn2+. These features facilitate fast ion transfer kinetics and inhibit water-induced side reactions. Furthermore, experimental results and theoretical simulations confirm that the presence of fly ash particles in FACNF separators effectively accommodate the preferential deposition of Zn(002) planes, due to the weak chemical affinity between Zn(002) plane and fly ash, to mitigate dendrite formation and growth. Consequently, the utilization of FACNF separators causes an impressive cycling performance in both Zn||Zn symmetric cells (1600 h at 2 mA cm-2/1 mAh cm-2) and Zn||(NH4)2V10O25 (NVO) full cells (4000 cycles with the capacity retention of 92.1% at 5 A g-1). Furthermore, the assembled pouch cells can steadily support digital thermometer over two months without generating gas and volume expansion. This work provides new insights for achieving crystallographic uniformity in Zn anodes and realizing cost-effective and long-lasting aqueous zinc-ion batteries (AZIBs).

Establishing Pinhole Deposition Mode of Zn via Scalable Monolayer Graphene Film

The uneven texture evolution of Zn during electrodeposition would adversely impact upon the lifespan of aqueous Zn metal batteries. To address this issue, tremendous endeavors are made to induce Zn(002) orientational deposition employing graphene and its derivatives. Nevertheless, the effect of prototype graphene film over Zn deposition behavior has garnered less attention. Here, it is attempted to solve such a puzzle via utilizing transferred high-quality graphene film with controllable layer numbers in a scalable manner on a Zn foil. The multilayer graphene fails to facilitate a Zn epitaxial deposition, whereas the monolayer film with slight breakages steers a unique pinhole deposition mode. In-depth electrochemical measurements and theoretical simulations discover that the transferred graphene film not only acts as an armor to inhibit side reactions but also serves as a buffer layer to homogenize initial Zn nucleation and decrease Zn migration barrier, accordingly enabling a smooth deposition layer with closely stacked polycrystalline domains. As a result, both assembled symmetric and full cells manage to deliver satisfactory electrochemical performances. This study proposes a concept of "pinhole deposition" to dictate Zn electrodeposition and broadens the horizons of graphene-modified Zn anodes.

"Soggy-Sand" Chemistry for High-Voltage Aqueous Zinc-Ion Batteries

The narrow electrochemical stability window, deleterious side reactions, and zinc dendrites prevent the use of aqueous zinc-ion batteries. Here, aqueous "soggy-sand" electrolytes (synergistic electrolyte-insulator dispersions) are developed for achieving high-voltage Zn-ion batteries. How these electrolytes bring a unique combination of benefits, synergizing the advantages of solid and liquid electrolytes is revealed. The oxide additions adsorb water molecules and trap anions, causing a network of space charge layers with increased Zn2+ transference number and reduced interfacial resistance. They beneficially modify the hydrogen bond network and solvation structures, thereby influencing the mechanical and electrochemical properties, and causing the Mn2+ in the solution to be oxidized. As a result, the best performing Al2 O3 -based "soggy-sand" electrolyte exhibits a long life of 2500 h in Zn||Zn cells. Furthermore, it increases the charging cut-off voltage for Zn/MnO2 cells to 2 V, achieving higher specific capacities. Even with amass loading of 10 mgMnO2 cm-2 , it yields a promising specific capacity of 189 mAh g-1 at 1 A g-1 after 500 cycles. The concept of "soggy-sand" chemistry provides a new approach to design powerful and universal electrolytes for aqueous batteries.

Dendrite-Free Zn Anode Endowed by Facile Al-Complex Coating for Long-Cycled Aqueous Zn-Ion Batteries

Side reactions and dendrite growth on the zinc metal anode surface seriously damage the shelf life and calendar life of Zn-based batteries. Here, an Al-complexed artificial interfacial layer is constructed on the Zn surface (denoted as Al-complex@Zn) by a low-cost, facile, and scalable chemical method. The Al-complex interfacial layer improves the wettability of the electrolyte. Meanwhile, the Al-complex layer not only inhibits the side reaction by a physical barrier on the Zn surface but also regulates the zinc-ion flux to realize the uniform deposition of Zn2+. The Zn//Zn symmetric cell with an Al-complex layer has realized an ultralong cycle life of 2400 h and an extremely low polarization voltage of 20 mV (1 mA cm-2, 0.5 mAh cm-2), surpassing those reported in most literature. Furthermore, when an Al-complex@Zn//NaV3O8·1.5H2O (NVO) full cell is assembled, a high capacity retention of 92.5% is achieved over 1000 cycles at a current density of 4 A g-1. This work provides a facile and low-cost strategy on the modification of zinc anode to realize long-cycled aqueous Zn-ion batteries.