Aqueous Zinc Batteries Research Articles

A Fluorine-Free Organic/Inorganic Interphase for Highly Reversible Aqueous Zinc Batteries.

Construction of robust solid electrolyte interphases (SEIs) has proved effective in mitigating dendrite growth and side reactions of zinc (Zn) anodes in aqueous electrolytes. Fluorinated SEIs, in particular, have garnered significant attention due to their exceptional electrochemical stability and high Zn2+ conductivity. However, the formation of such SEIs typically relies on the use of fluorine (F)-containing precursors, which inadvertently raise environmental and biological concerns because they show high resistance to degradation in natural environments. Herein, we develop an F-free organic/inorganic hybrid SEI for aqueous Zn batteries using a low-cost N-acetyl-D-glucosamine (NAG) electrolyte additive. The NAG additive not only modulates the solvation structure of Zn2+ but also preferentially adsorbs on the Zn anode to promote the in situ formation of a robust organic (Zn chelates)/inorganic (ZnS and ZnCO3) hybrid SEI layer, thereby enhancing Zn2+ de-solvation kinetics and Zn plating/stripping reversibility. Consequently, the Zn anode exhibits a long-term cycling over 6500h at 0.5mAcm‒2, a high average Coulombic efficiency of 99.6% at 1mAcm‒2, and greatly extended cycling stability in full cells (up to 2000 cycles). Our electrolyte design paves a promising avenue toward practical Zn batteries that combine performance, cost-effectiveness, and eco-friendliness.

Hydrophilic or Hydrophobic: Revealing the Role of an Ionic Liquid by an Interfacial Hydrogen Bond in an Aqueous Zinc Battery.

Hydrogen evolution reaction (HER) on Zn-metal constrains the development of aqueous zinc batteries. Ionic liquid (IL) additives are proposed to isolate interfacial H2O and suppress HER. However, whether the addition of either hydrophilic or hydrophobic ILs can effectively suppress HER seems "contradictory". Herein, although the disproportionation of hydrophilic/hydrophobic properties leads to an interfacial H2O content difference, we demonstrate that both hydrophilic and hydrophobic ILs present a consistent influence on the configuration of interfacial hydrogen bonds. Specifically, they both decrease the amount of weak hydrogen bonds and increase the number of strong hydrogen bonds simultaneously, which makes the deprotonation of H2O (related to HER) more difficult. In addition, by capturing the dynamic evolution of interfacial hydrogen bonds through in situ spectroscopy, we successfully correlate the evolution of interfacial hydrogen bonds with detrimental HER parasitic reaction on the Zn-metal surface. This study enhances the understanding of interface engineering from the perspective of interfacial hydrogen bond dynamic evolution.

Chelation Effect Induced Robust Biomass Protective Layer for Aqueous Zn Metal Anode

AbstractThe detrimental dendrite growth and hydrogen evolution corrosion on Zn metal anode greatly hinder the implement of aqueous zinc batteries. Constructing a stable solid electrolyte interphase (SEI) on Zn anode is considered an effective strategy to prolong the cells life. Herein, by using poly(N‐[2‐(3,4‐dihydroxyphenyl)ethyl]‐2‐methylacrylamide) (PDMA) as a case study, the impact of Zn2+ chelation effect on SEI layer generation is systematically investigated. The DMA monomer tends to form a robust PDMA layer on Zn anode with a higher crosslinking degree with the assistant of Zn2+. The Zn─O interaction between Zn metal and PDMA guarantees the long‐term protection efficiency of the SEI layer and uniformizes the Zn nucleation. Moreover, the Zn2+ desolvation can be propelled by the zincophilic hydroxyl groups in PDMA. As expected, the Zn symmetric cell with in‐PDMA showcases an extended lifespan of over 3800 h. The Zn||NVO full cell maintains a capacity of 150 mAh g−1 after 1000 cycles at 1 A g−1. This work is believed to guide the future aqueous Zn anode design based on the protective layer engineering.

Regulating Extra-Layer Ion Channels in the Conductive V2O5 Hydrogel Cathode.

High-power energy storage devices rely on the synergistic coordination of ion and electron transport. Here, an extra-layer channels engineering strategy is presented for developing high power and energy density cathode materials for aqueous zinc batteries (AZIBs). This approach utilizes a cation-induced self-assembly process to form conductive hydrogels with extra-layer channels by adding diverse cations (Li+, Na+, K+, Mg2+, Zn2+, Al3+, and NH4 +) into the carbon nanotubes (CNTs) ink dispersed hydrated V2O5 (h-V2O5) nanowires. The cations bridge h-V2O5 nanowires and create self-assembly network on the CNT surfaces, providing extra-layer ion channels beyond the intrinsic interlayer of h-V2O5. These external channels exhibit distinct properties depending on the cations, significantly influencing the performance of V2O5 hydrogel cathode for AZIBs. Larger cations reduce Zn2+ migration resistance enhancing diffusion kinetics; smaller cations strengthen the M─O bond, improving structural stability. For instance, K-V2O5/CNT demonstrates an initial specific capacity of up to 618 mAh g-1 at 0.2 A g-1 and retains a capacity of 248 mAh g-1 even at 20 A g-1. In contrast, the Zn-V2O5/CNT maintains excellent cycling stability, with 230 mAh g-1 after 700 cycles at 1 A g-1. This offers a versatile platform for tailoring ion transport channels in hydrogel cathodes for ZIBs.

Engineering Artificial Protrusions of Zn Anodes for Aqueous Zinc Batteries.

Uncontrollable dendrite growth can jeopardize the cycle life of aqueous Zn batteries. Here, we propose a general strategy of engineering artificial protrusions (APs) on the electrode surface to regulate the distribution of the electrode interface electric field and induce stable Zn plating/stripping for Zn batteries. The junction-free AP-Cu network is constructed on Cu foil by an ultrafast Joule-heating-welding method. COMSOL simulation reveals that a stronger microelectric field is formed around the individual AP, which can effectively regulate a uniform nucleation of Zn on the AP-Cu network. Guided by the structural advantages of the AP design, the AP-Cu∥Zn cell delivers an average Coulombic efficiency (CE) of 99.85% at 2 C with an areal capacity of 1.77 mAh cm-2 for over 3000 cycles. Moreover, the AP design enables stable cycling of both Zn|AP-Cu∥V2O5 and anode-free AP-Cu∥Br2 full cells, providing a promising strategy for the development of high-performance energy storage devices.

Six-electron-conversion selenium cathodes stabilized by dead-selenium revitalizer for aqueous zinc batteries

Aqueous zinc batteries are attractive for large-scale energy storage due to their inherent safety and sustainability. However, their widespread application has been constrained by limited energy density, underscoring a high demand of advanced cathodes with large capacity and high redox potential. Here, we report a reversible high-capacity six-electron-conversion Se cathode undergoing a ZnSe↔Se↔SeCl4 reaction, with Br−/Brn− redox couple effectively stabilizes the Zn | |Se cell. This Se conversion, initiated in a ZnCl2-based hydrogel electrolyte, presents rapid capacity decay (from 1937.3 to 394.1 mAh gSe−1 after only 50 cycles at 0.5 A gSe−1) primarily due to the dissolution of SeCl4 and its subsequent migration to the Zn anode, resulting in dead Se passivation. To address this, we incorporate the Br−/Brn− redox couple into the Zn | |Se cell by introducing bromide salt as an electrolyte additive. The generated Brn− species acts as a dead-Se revitalizer by reacting with Se passivation on the Zn anode and regenerating active Se for the cathode reaction. Consequently, the cycling stability of the Zn | |Se cell is improved, maintaining 1246.8 mAh gSe−1 after 50 cycles. Moreover, the Zn | |Se cell exhibits a specific capacity of 2077.6 mAh gSe−1 and specific energy of 404.2 Wh kg−1 based on the overall cell reaction.

Optimizing Amphoteric Cellulose Additives with Complexation-Adsorption Mechanisms to Stabilize the Zn Anode.

The growth of Zn dendrites and interfacial side reactions are two critical challenges impeding the commercial application of aqueous zinc batteries (AZBs). The amphoteric electrolyte additive is considered a convenient and efficient strategy to stabilize the Zn anode. However, most studies overlook the critical impacts of their charge compositions and the corresponding mechanisms on Zn2+ electroplating behavior. Here, we use amphoteric cellulose as an exemplary research object, as the number of positive/negative groups can be easily and effectively controlled. We elucidate in detail the interplay between the complexation and adsorption mechanisms of the amphoteric cellulose additive in AZBs. Specifically, the amphoteric cellulose additive not only guides and regulates Zn2+ deposition but also forms a uniform protective layer on the Zn surface. As a result, the optimal additive enables dendrite-free and side-reaction-suppressed AZBs, leading to a Zn||Zn cell with a high depth of discharge of 68.4%, and a Zn||NH4V4O10 cell with a high reversible specific capacity of 310 mAh g-1. This work demonstrates a promising strategy by elucidating the role of charge composition in electrolyte additive design, advancing the development of stable AZBs.

General Oxygen Vacancy Engineering by Molten Zinc to Regulate Anode Redox for Durable Aqueous Zinc-Iodine Batteries.

Oxygen vacancy engineering plays a crucial role in regulating surface chemistry for managing redox behaviors. However, controllable implantation of oxygen vacancy and safe and cost-effective production remain challenging. Herein, we report a general molten zinc reduction technology to prepare oxygen-deficient oxides with tunable vacancy content, synthetic universality, and industrial compatibility under mildly elevated temperature. Taking TiO2 as an example, theoretical study demonstrates thermodynamically favorable zinc affinity on TiO2 with increasing surface coverage supporting molten Zn supply. Featuring favorable electronic structures and inferior hydrogen evolution activity, TiO2-x nanoparticles were used to decorate aqueous Zn anodes, which demonstrate much improved cycling stability, verified by theoretical and in situ and ex situ investigations. Eventually, zinc-iodine batteries were assembled using modified Zn anodes, which achieved favorable cycling performance due to the regulated anode redox and alleviated self-discharge behaviors. This work provides a general oxygen vacancy engineering technology with an in-depth understanding for durable aqueous zinc batteries and related systems.

Salt-Based Electrolyte Additives for Regulating the Interface Chemistry of Zinc Metal Anodes in High-Performance Aqueous Zinc Batteries.

Aqueous zinc-metal batteries (AZMBs) are emerging as a promising green and low-cost energy storage solution, distinguished by their high safety and environmental friendliness. However, the industrialization of AZMBs is currently hindered by significant challenges, particularly uncontrollable dendritic growth and side reactions at the zinc metal anode interface, which severely limit their large-scale application. To address these issues, salt-based electrolyte additives have emerged as a straightforward, economical, and practical solution. This review systematically classifies and analyzes the working mechanisms of inorganic, organic, and ammonium salt-based additives, elucidating their roles in regulating solvation structures, hydrogen bond networks, pH levels, interfacial protective layers, electric fields, and Zn2+ deposition behaviors. These additives enhance anode stability and mitigate side reactions, thereby improving overall electrochemical performance. Additionally, the review offers valuable insights into future directions for the development of salt-based electrolyte additives, providing essential guidance for advancing research in this field.

Synergistic Gradient Design of a Sandwich‐Structured Heterogeneous Anode for Improved Stability in Aqueous Zinc‐Ion Batteries

AbstractAqueous Zn‐ion batteries provide a low‐cost energy storage solution but face challenges such as dendrite formation and interface instability, which become more pronounced at high currents and capacities. Herein, a scalable sandwich‐structured heterogeneous anode is proposed for aqueous zinc batteries that integrate three functionally synergistic layers. A robust 3D ZnO@C substrate (from calcined Bio‐MOF‐100, BMC) with dense nucleation sites guides orderly Zn deposition, while a controllable pre‐deposited Zn intermediate layer precisely regulates Zn2⁺ flux. An artificial indium‐based protective top‐layer that chemically isolates the active Zn from the electrolyte, effectively suppresses interfacial corrosion, and enhances interlayer contact to minimize impedance while maintaining structural integrity during cycling. The structural synergies endow the symmetric cell with an ultra‐long cycle life exceeding 2000 h and stable Zn plating/stripping at a remarkable depth of discharge (76%) under high current/areal capacity conditions (6 mA cm−2/12 mAh cm−2). Additionally, the BMC@Zn@In//(NH4)2V10O25·8H2O full battery achieves a stable lifespan of 5000 cycles, while the BMC@Zn@In//activated carbon hybrid supercapacitor demonstrates an impressive cycle life of 16 000 cycles. This study identifies a synergistic mechanism for an ultra‐stable Zn anode with promising applications in aqueous Zn‐ion batteries.

Towards High-Performance Aqueous Zn-Organic Batteries via Using I--Based Active Electrolyte.

Organic cathodes possess inherent structural diversity and fast redox kinetics, showing great application prospects in aqueous Zn batteries. Nevertheless, most of the reported organic cathodes display low average working voltage resulting in poor energy density. Herein, diquinoxalino [2,3-a:2',3'-c] phenazine (HATN)@CMK-3 composite is utilized as cathode for aqueous zinc battery, which combines the Zn2+ and H+ co-storage and I-/I0 conversion by introducing I--based active additive into 0.5M Zn(OTf)2 electrolyte. The in situ/ex situ analyses and computational studies disclose that HATN@CMK-3 with C═N groups not only stores Zn2+ and H+ ions at low potential but also acts as a substrate to promote the conversion reaction of I-/I0 at high potential. Accordingly, the Zn//HATN@CMK-3 cell delivers a high average voltage of 0.75V, prominent long-life (10000 cycles) and, high energy density (198Wh kg-1). Remarkably, under high mass loading (10mgcm-2) or low-temperature conditions, the cell still achieves decent capacity and cycle stability.

Towards High‐Performance Aqueous Zn‐Organic Batteries via Using I‐‐Based Active Electrolyte

Organic cathodes possess inherent structural diversity and fast redox kinetics, showing great application prospects in aqueous Zn batteries. Nevertheless, most of the reported organic cathodes display low average working voltage resulting in poor energy density. Herein, diquinoxalino [2,3‐a:2’,3’‐c] phenazine (HATN)@CMK‐3 composite is utilized as cathode for aqueous zinc battery, which combines the Zn2+ and H+ co‐storage and I‐/I0 conversion by introducing I‐‐based active additive into 0.5 M Zn(OTf)2 electrolyte. The in‐situ/ex‐situ analyses and computational studies disclose that HATN@CMK‐3 with C=N groups not only stores Zn2+ and H+ ions at low potential, but also acts as a substrate to promote the conversion reaction of I‐/I0 at high potential. Accordingly, the Zn//HATN@CMK‐3 cell delivers a high average voltage of 0.75 V, prominent long‐life (10000 cycles) and high energy density (198 Wh kg‐1). Remarkably, under high mass‐loading (10 mg cm‐2) or low‐temperature conditions, the cell still achieves decent capacity and cycle stability.

Non-destructive electrochemical diagnosis of failure mechanisms in aqueous zinc batteries

Non-destructive electrochemical diagnosis of failure mechanisms in aqueous zinc batteries

Hydrogel electrolyte design for long-lifespan aqueous zinc batteries to realize a 99% Coulombic efficiency at 90°C

Hydrogel electrolyte design for long-lifespan aqueous zinc batteries to realize a 99% Coulombic efficiency at 90°C

Perinone with fast proton insertion chemistry for durable aqueous zinc battery

Perinone with fast proton insertion chemistry for durable aqueous zinc battery

Photo-driven rechargeable aqueous zinc batteries based on NiCo-layered double hydroxide nano composite cathodes

Photo-driven rechargeable aqueous zinc batteries based on NiCo-layered double hydroxide nano composite cathodes

Screening and Design of Aqueous Zinc Battery Electrolytes Based on the Multimodal Optimization of Molecular Simulation.

Aqueous batteries, such as aqueous zinc-ion batteries (AZIB), have garnered significant attention because of their advantages in intrinsic safety, low cost, and eco-friendliness. However, aqueous electrolytes tend to freeze at low temperatures, which limits their potential industrial applications. Thus, one of the core challenges in aqueous electrolyte design is optimizing the formula to prevent freezing while maintaining good ion conductivity. However, the experimental trial-and-error approach is inefficient for this purpose, and existing simulation tools are either inaccurate or too expensive for high-throughput phase transition predictions. In this work, we employ a small amount of experimental data and differentiable simulation techniques to develop a multimodal optimization workflow. With minimal human intervention, this workflow significantly enhances the prediction power of classical force fields for electrical conductivity. Most importantly, the simulated electrical conductivity can serve as an effective predictor of electrolyte freezing at low temperatures. Generally, the workflow developed in this work introduces a new paradigm for electrolyte design. This paradigm leverages both easily measurable experimental data and fast simulation techniques to predict properties that are challenging to access by using either approach alone.

Dynamic Modulation of Keto-Enol Tautomerism in Electrolytes for Aqueous Zinc Batteries.

The reversibility of zinc (Zn) anode is subject to adverse reactions. Herein we design a dynamic modulation strategy via enol-keto tautomerism to inhibit the side reactions, thus improving the reversibility of the Zn anode. Density functional theory calculations and experimental results demonstrate the keto form of additives can be adsorbed on the Zn anode, inhibiting dendrites' growth, while the enol form can serve as a bidentate ligand to participate in the construction of solvation sheath for Zn2+, enhancing the kinetics of Zn2+ transport, simultaneously suppressing water activity and reducing HER and corrosion. After desolvation, the enol form of additives can react with by-products, further weakening passivation and morphological variation. Consequently, the Zn anode with optimal additive achieves high reversibility, where Zn||Zn symmetric cells operate over 4000 h at 10 mA cm-2/10 mAh cm-2, Zn||Cu asymmetric cells have a life for 930 h at 10 mA cm-2/10 mAh cm-2. Further, this dynamic modulation enables Zn||V2O5 full cells to work over 5000 cycles with a capacity retention of 83% at 5 A g-1, and the Zn||Br2 pouch cells deliver a high capacity of ~ 180 mAh. This study offers an original perspective on the dynamic regulation of the Zn anode.

Sustainable Release of Zincophilic Metal Ions from Separator Proactively Drives Interfacial Stabilization for Durable Zinc Anode

AbstractOne of the important challenges in advancing aqueous zinc‐ion batteries is the separator, which is crucial for promoting stable electrode‐electrolyte interface and energy density of the battery. Herein, this study introduces a metal ion‐activated air‐laid paper (ALP Act) as an alternative for traditional glass fiber separators with big thickness and weight. Notably, the sustainable release of metal ions facilitates in situ interface engineering, thus creating a surface layer with high zinc affinity to promote the uniform migration and deposition of zinc ions. By continuously adjusting the electrode‐electrolyte interface, the behaviors of dendrite growth and side reactions are effectively suppressed. Consequently, the ALP Act with continuous metal‐ion release function enables the zinc anode to attain a 21‐fold increase in running life beyond 3700 h compared with the conventional glass fiber separator at 1 mA cm−2 and l mAh cm−2. The Zn||Cu battery also achieves a remarkable Coulombic efficiency of 99.18% for 2000 h (1 mA cm−2/1 mAh cm−2). The assembled Zn||NVO battery exhibits a lifespan of 3000 cycles for the charge and discharge cycles at 3 A g−1. This research offers a new avenue for the separator to achieve low‐cost, long‐lasting, and energy‐dense aqueous zinc batteries.

Polyacrylic Acid‐Modified Gel Electrolytes for Enhanced Electrochemical Performance in Aqueous Zinc Batteries

AbstractGel electrolytes are widely used in aqueous zinc batteries to alleviate water‐related issues. In this study, we develop a new gel electrolyte by introducing a small amount of polymer additive, inspired by electrolyte additives in liquid electrolytes. The introduction of polyacrylic acid (PAA) additive improves the ionic diffusion coefficient inside the gel electrolyte and enables uniform Zn deposition, enhancing the reversibility of Zn batteries. As a result, the Zn||Mg0.1V2O5 batteries using the modified electrolyte show a maximum capacity of 300 mAh g−1 at a current density of 0.5 A g−1 and remain stable over 300 cycles. In contrast, the batteries without the PAA additive suffer from rapid capacity decay within 150 cycles under the same conditions. This study presents a simple and cost‐effective method of gel electrolyte additive engineering to enhance the performance of aqueous zinc batteries.