应用于水系锌离子电池正极的钒基材料和锰基材料的形貌调控

Conspectus Zinc-ion batteries (ZIBs) are highly promising for large-scale energy storage because of their safety, high energy/power density, low cost, and eco-friendliness. Vanadium-based compounds are attractive cathodes because of their versatile structures and multielectron redox processes (+5 to +3), leading to high capacity. Layered structures or 3-dimensional open tunnel frameworks allow easy movement of zinc-ions without breaking the structure apart, offering superior rate-performance. However, challenges such as dissolution and phase transformation hinder the long-term stability of vanadium-based cathodes in ZIBs. Although significant research has been dedicated to understanding the mechanisms and developing high-performance vanadium-based cathodes, uncertainties still exist regarding the critical mechanisms of energy storage and dissolution, the actual active phase and the specific optimization strategy. For example, it is unclear whether materials such as α-V2O5, VO2, and V2O3 serve as the active phase or undergo phase transformations during cycling. Additionally, the root cause of V-dissolution and the role of byproducts such as Zn3(OH)2V2O7·2H2O in ZIBs are debated. In this account, we aim to outline a clear and comprehensive roadmap for V-based cathodes in ZIBs. On the basis of our studies, we analyzed intrinsic crystal structures and their correlation with performance to guide the design of V-based materials with high-capacity and high-stability for ZIBs. Then, we revealed the underlying mechanisms of energy storage and instability, enabling more effective design and optimization of V-based cathodes. After identifying the key challenges, we proposed effective design principles to achieve high cycling performance of V-based cathodes and outlined future development directions toward their practical application. Vanadium-based compounds include [VO4] tetrahedrons, [VO5] square pyramids, and [VO6] octahedra, which are connected through a cocorner, coedge and coplane. The [VO4] tetrahedron is inactive, and the [VO5] square pyramid is unstable in aqueous solutions because water attacks the exposed vanadium, whereas stable [VO6] octahedra are desirable because of their ability to reduce from +5 to +3 with minimal structural distortion. Therefore, high-performance vanadium-based oxides in ZIBs should maintain intact [VO6] octahedra while avoiding [VO4] tetrahedra or [VO5] square pyramids. The energy storage mechanism involves H2O/H+/Zn2+ coinsertion. The existence of interlayer water in V-based cathodes significantly improves the rate and cycling performance by expanding galleries, screening Zn2+ electrostatically via solvation, reducing ion diffusion energy barriers, and increasing layer flexibility. The insertion of H+/Zn2+ and the instability of V-based cathodes lead to the formation of byproducts such as basic zinc salts (i.e., Zn4SO4(OH)6·nH2O) and dead vanadium (Zn3(OH)2V2O7·2H2O), whose reversibility strongly affects long-term stability. To increase the cycling stability of vanadium-based cathodes, strategies such as electrolyte modulation and coating have been proposed to decrease water attack on the surface of V-oxides, thereby affecting the formation of byproducts. Additionally, in situ electrochemical transformation, ion preintercalation, and ion exchange were explored to prepare intrinsically stable V-based cathodes with enhanced performance. Furthermore, future research should focus on revealing atomic-scale mechanisms through advanced in situ characterization and theoretical calculations, enhancing rate-performance by facilitating ion/electron diffusion, promoting cycling stability by developing highly stable cathodes and refining interface engineering, and scaling up vanadium-based cathodes for practical ZIB applications.

… high-energy-density cathode materials for aqueous Zn-ion batteries is still challenging. Here… of a carbon-confined vanadium trioxide (V 2 O 3 @C) microsphere cathode is demonstrated. …

… the capacity decay of vanadium-based cathodes. Through a … dissolved vanadium ions react with zinc salts or layered zinc … cycling of vanadium-based cathodes in aqueous electrolytes, …

… material for aqueous zinc ion batteries (… Zn 2+ deintercalation kinetics and lead to poor cycling stability. This study explores the enhancement of vanadium pentoxide (V 2 O 5 ) cathodes …

Abstract The growing demand for energy storage has inspired researchers’ exploration of advanced batteries. Aqueous zinc ion batteries (ZIBs) are promising secondary chemical battery system that can be selected and pursued. Rechargeable ZIBs possess merits of high security, low cost, environmental friendliness, and competitive performance, and they are received a lot of attention. However, the development of suitable zinc ion intercalation-type cathode materials is still a big challenge, resulting in failing to meet the commercial needs of ZIBs. Both vanadium-based and manganese-based compounds are representative of the most advanced and most widely used rechargeable ZIBs electrodes. The valence state of vanadium is +2 ∼ +5, which can realize multi-electron transfer in the redox reaction and has a high specific capacity. Most of the manganese-based compounds have tunnel structure or three-dimensional space frame, with enough space to accommodate zinc ions. In order to understand the energy storage mechanism and electrochemical performance of these two materials, a specialized review focusing on state-of-the-art developments is needed. This review offers access for researchers to keep abreast of the research progress of cathode materials for ZIBs. The latest advanced researches in vanadium-based and manganese-based cathode materials applied in aqueous ZIBs are highlighted. This article will provide useful guidance for future studies on cathode materials and aqueous ZIBs.

… -intercalating vanadium oxides cathodes, analyzes their crystal structure changes and Zn 2… on the electrochemical capacity of vanadium oxides cathodes. Additionally, this review …

… the recent progress in developments of vanadium-based materials, … and Zn-ion transport mechanism. Finally, we presented the future prospects of developing aqueous zinc-ion batteries …

… Exploring suitable high-capacity V 2 O 5 -based cathode materials is essential for the rapid advancement of aqueous zinc ion batteries (ZIBs). However, the typical problem of slow Zn 2…

… In conclusion, the insertion of various metal ions into vanadium … on the electrochemical performance of vanadium oxide. … for the development of vanadium-based cathode materials with …

Aqueous zinc ion batteries (AZIBs) are an ideal choice for a new generation of large energy storage devices because of their high safety and low cost. Vanadium oxide-based materials have attracted great attention in the field of AZIB cathode materials due to their high theoretical capacity resulting from their rich oxidation states. However, the serious structural collapse and low intrinsic conductivity of vanadium oxide-based materials cause rapid capacity fading, which hinders their further applications in AZIB cathode materials. Here, the structural characteristics and energy storage mechanisms of vanadium oxide-based materials are reviewed, and the optimization strategies of vanadium oxide-based cathode materials are summarized, including substitutional doping, vacancy engineering, interlayer engineering, and structural composite. Finally, the future research and development direction of vanadium oxide-based AZIBs are prospected in terms of cathode, anode, electrolyte, non-electrode components, and recovery technology.

In recent years, aqueous zinc‐ion batteries (AZIBs) have become an ideal candidate technology for large‐scale energy storage systems due to their high safety, low cost, and environmentally friendly characteristics. However, problems such as the dissolution of cathode materials and low conductivity have hindered the practical application of AZIBs. Vanadium‐based cathode materials exhibit significant advantages in AZIBs by their multivalent redox activity (V2+/V5+), tunable layered/tunneled crystal structure, and high theoretical capacity (589 mAh g−1). In this paper, the energy storage mechanism of vanadium‐based cathode materials, material classification, and their modification strategies, including pre‐intercalation, defect engineering, ion doping, nanostructure design, and composite construction are systematically reviewed. Through these in‐depth analyses and summaries, it is expected to provide guidance and reference for the design and development of cathodes for high‐performance zinc‐ion batteries in the future.

Abstract Aqueous zinc-ion batteries (ZIBs) have got wide attention with the increasing demands for energy resource recently. It has a number of merits compared with lithium-ion batteries, such as enhanced safety, low cost and environmental friendliness. Vanadium-based materials have been developed to serve as the cathodes of ZIBs for many years. But there are also some challenges to construct high performance ZIBs in the future. Herein, we reviewed the research progress of vanadium-based cathodes and discussed the energy storage mechanisms in ZIBs. In addition, we summarized the major challenges faced by vanadium-based cathodes and the corresponding ways to improve electrochemical performance of ZIBs. Finally, some excellent vanadium-based cathodes are summarized to pave the way for future research in ZIBs.

… During the discharged process of ZIB, the zinc ions can embed in the vanadium oxide cathode with ease, due to the structures of vanadium oxides with a large layered or tunnel-like …

… cathode materials for aqueous Zn-ion batteries with satisfactory electrochemical performance. Nevertheless, the NHVO cathode is … vanadium (V) and oxygen (O) dual defects into NHVO …

This review summarizes the recent research progress in vanadium/manganese-based composite materials, focusing on green synthesis strategies employing the composite support materials CNTs, GO, MOF-derived carbon, MXenes and other hybrid carriers.

… vanadium oxide cathode material is widely regarded as a promising candidate for aqueous zinc-ion batteries … spacing for fast Zn 2+ transport, and facilitating the exposure of more Zn 2+ …

… encapsulation may be another efficient strategy for alleviating the vanadium dissolution. Some carbon coated vanadium oxides as cathode were also reported with superior zinc-storage …

Aqueous zinc‐ion batteries (AZIBs) are regarded as promising electrochemical energy storage devices owing to its low cost, intrinsic safety, abundant zinc reserves, and ideal specific capacity. Compared with other cathode materials, manganese dioxide with high voltage, environmental protection, and high theoretical specific capacity receives considerable attention. However, the problems of structural instability, manganese dissolution, and poor electrical conductivity make the exploration of high‐performance manganese dioxide still a great challenge and impede its practical applications. Besides, zinc storage mechanisms involved are complex and somewhat controversial. To address these issues, tremendous efforts, such as surface engineering, heteroatoms doping, defect engineering, electrolyte modification, and some advanced characterization technologies, have been devoted to improving its electrochemical performance and illustrating zinc storage mechanism. In this review, we particularly focus on the classification of manganese dioxide based on crystal structures, zinc ions storage mechanisms, the existing challenges, and corresponding optimization strategies as well as structure–performance relationship. In the final section, the application perspectives of manganese oxide cathode materials in AZIBs are prospected.

Among various energy storage systems, aqueous zinc-ion batteries (AZIBs) are widely regarded as a promising option due to their high theoretical capacity, cost-effectiveness, and …

Safety issues of energy storage devices in daily life are receiving growing attention, together with resources and environmental concerns. Aqueous zinc ion batteries (AZIBs) have emerged as promising alternatives for extensive energy storage due to their ultra-high capacity, safety, and eco-friendliness. Manganese-based compounds are key to the functioning of AZIBs as the cathode materials thanks to their high operating voltage, substantial charge storage capacity, and eco-friendly characteristics. Despite these advantages, the development of high-performance Mn-based cathodes still faces the critical challenges of structural instability, manganese dissolution, and the relatively low conductivity. Primarily, the charge storage mechanism of manganese-based AZIBs is complex and subject to debate. In view of the above, this review focuses on the mostly investigated MnO2-based cathodes and comprehensively outlines the charge storage mechanisms of MnO2-based AZIBs. Current optimization strategies are systematically summarized and discussed. At last, the perspectives on elucidating advancing MnO2 cathodes are provided from the mechanistic, synthetic, and application-oriented aspects.

Layered manganese oxides adopting pre‐accommodated cations have drawn tremendous interest for the application as cathodes in aqueous zinc‐ion batteries (AZIBs) owing to their open 2D channels for fast ion‐diffusion and mild phase transition upon topochemical (de)intercalation processes. However, it is inevitable to see these “pillar” cations leaching from the hosts owing to the loose interaction with negatively charged Helmholtz planes within the hosts and shearing/bulking effects in 2D structures upon guest species (de)intercalation, which implies a limited modulation to prevent them from rapid performance decay. Herein, a new class of layered manganese oxides, Mg0.9Mn3O7·2.7H2O, is proposed for the first time, aims to achieve a robust cathode for high‐performance AZIBs. The cathode can deliver a high capacity of 312 mAh g−1 at 0.2 A g−1 and exceptional cycling stability with 92% capacity retention after 5 000 cycles at 5 A g−1. The comprehensive characterizations elucidate its peculiar motif of pined Mg‐□Mn‐Mg dumbbell configuration along with interstratified hydrogen bond responsible for less Mn migration/dissolution and quasi‐zero‐strain characters. The revealed new structure‐function insights can open up an avenue toward the rational design of superstructural cathodes for reversible AZIBs.

… the transport kinetics of zinc ions. From the perspective of … Zinc-ion storage mechanisms: the reversible Zn 2+ insertion/extraction; the reversible interposition and deintercalation of Zn …

Abstract Aqueous zinc-ion batteries (AZIBs) have emerged … , manganese-based oxides are promising cathode materials … -induced manganese dissolution, slow diffusion kinetics of Zn 2…

Conspectus Frequent safety accidents of lithium-ion batteries (LIBs) originating from the utilization of flammable electrolytes urges the battery community to develop a safe substitute. This safety background is a boom for aqueous batteries (ABs) which employ aqueous electrolytes to address safety concerns. Recently, ABs have experienced a rapid advance because various battery chemistries have been successively developed, e.g., aqueous Zn batteries (AZBs), aqueous LIBs, aqueous sodium-ion battery, etc. Impeded by the narrow voltage window of aqueous electrolytes, however, the majorities of cathode materials with high operation potential employed in traditional nonaqueous batteries are excluded from the range of ABs cathodes, leading to a low energy density. Directly using metal as an anode is likely to improve the energy density, whereas most of the reported metal anodes, e.g., lithium, sodium, magnesium, etc., cannot run in aqueous electrolytes. One exceptional case is the Zn metal anode that permits theoretically high energy density AZBs due to triple merits: (1) the Zn metal anode exhibits a low redox potential (-0.76 V vs standard hydrogen electrode, SHE), taking the best advantage of the limited voltage window of aqueous electrolytes; (2) Zn metal anode with mild protection can easily maintain its chemical stability in aqueous medium; (3) Zn metal anode releases a high specific capacity of 820 mAh g-1. AZBs thus exhibit a rapid development, especially in developing high specific capacity cathode materials such as MnO2and V2O5, and the corresponding structure modification. Despite these spurring achievements, the overall energy density of the whole AZB device is still unsatisfactory.In this Account, we initially present the energy density state of AZBs, where a detailed discussion is given to the energy bottleneck of current cathode materials. Meanwhile, the corresponding strategies that are considered as the first-stage attempt to enhance energy density are discussed, including mediating interlayer spacing, introducing oxygen vacancy, and using high-voltage cathode materials. Due to the unsatisfactory energy density, we then propose a systemic methodology of cathode engineering to renew the energy blueprint of AZBs. Specifically, we show the high possibility of employing conversion-type cathodes with the capability of multiple-electron transfer reaction, e.g., sulfur, selenium, iodine, etc., to remarkably enhance the energy density of AZBs. In addition, strengthening the utilization of cathode active material such as the activation, stabilization, or introduction of metal active centers is highlighted as a branch of cathode engineering to address the energy density issue of AZBs. Finally, we attempt to summarize the remaining challenges and possible solutions to address the energy density issue of AZBs, such as reducing the proportion of electrochemically inactive materials, increasing the cathode loading mass, and avoiding the excessive usage of Zn anode. Overall, we believe this Account can shed light on the promising directions to design a practical high energy density AZBs.

Aqueous zinc-ion batteries (AZIBs), as one of the most promising energy storage devices, have attracted widespread attention owing to their abundant resources, environmental friendliness, and high safety. As a crucial component of AZIBs, the electrochemical performance of cathode materials plays a decisive role in battery performance, thus necessitating in-depth investigations into the structure and properties of cathode materials. Manganese dioxide (MnO2), as a cathode material for AZIBs, has garnered significant interest owing to advantages such as the low cost of manganese, stable structure, simple synthesis process, and abundant raw materials. Additionally, it exhibits high specific capacity and tunable cycling performance. However, MnO2 as a cathode in AZIBs is plagued by structural deformation, side reactions, and the Jahn-Teller effect during cycling. Therefore, it is essential to comprehensively review the research progress, reaction mechanisms, and optimization strategies of MnO2 in AZIBs. Herein, MnO2 is taken as the research focus. Firstly, we comprehensively summarize the development status and research progress of MnO2 materials as cathodes for AZIBs. Subsequently, we conduct an in-depth analysis of the structural evolution and Zn2+ storage mechanisms of MnO2 during cycling, including the conversion reaction mechanism, Zn2+ intercalation mechanism, dissolution-deposition mechanism, and H+/Zn2+ co-intercalation mechanism. Building on this, various optimization strategies such as structural control, morphological regulation, defect engineering, and electrolyte development are systematically reviewed. Finally, we outline future research directions for high-performance MnO2 cathodes, put forward a rational research roadmap to maximize the electrochemical properties of MnO2, and facilitate the construction of stable AZIBs.

Aqueous zinc‐ion batteries (AZIBs) have emerged as a promising energy storage solution due to their eco‐friendly aqueous electrolytes, high theoretical capacity of zinc anodes, and abundant global zinc reserves. Among the reported cathode materials, manganese‐based cathodes are widely used in AZIBs due to their high theoretical capacity and low cost. However, practical applications of manganese‐based cathodes face several challenges, including structural instability, low electrical conductivity, and slow diffusion kinetics. This review begins by exploring the crystalline structures of manganese‐based compounds commonly used in AZIBs, systematically analyzing their reaction mechanisms. Furthermore, it examines the main challenges currently encountered by manganese‐based compounds in AZIBs. Addressing these challenges, this review summarizes corresponding optimization strategies, providing valuable references and insights for the development and application of manganese‐based cathodes in AZIBs.

This research reports the presence of a synergistic effect among vacancies, lattice water and nickel ions on enhancing the hydrated protons hopping via the Grotthuss mechanism for high performance zinc ion battery cathodes.

… The K 0.32 MnO 2 ∙0·15H 2 O is a promising cathode material for aqueous zinc-ion batteries… of layered MnO 2 as a cathode material for aqueous zinc-ion batteries (ZIBs) and elucidate …

… Aqueous zinc ion batteries (ZIBs) are attracting considerable attentions for … manganese oxide cathode materials suffer from the low intrinsic electronic conductivity, sluggish ions …

… Manganese oxides are ideal cathode materials for aqueous zinc ion batteries (AZIBs) due to their … Despite their promising characteristics, manganese oxides suffer from inherently low …

Aqueous zinc-ion batteries (AZIBs) are gaining significant attention due to their excellent safety, cost-effectiveness, and environmental friendliness, making them highly competitive energy storage solutions. Despite these advantages, the commercial application of AZIBs faces substantial challenges, particularly those related to performance limitations of cathode materials. Among potential candidates, vanadium dioxide (VO2) stands out due to its exceptional electrochemical properties and unique crystal structure, rendering it a promising cathode material for AZIB applications. The review summarizes the recent research progress on VO2 in AZIBs, analyzes its crystal structures (tetragonal VO2(A), monoclinic VO2(B, D, M), and rutile VO2(R)), morphology and energy storage mechanisms (Zn2+ insertion/extraction, H+/Zn2+ co-insertion/extraction, and chemical reaction mechanism), and discusses the relationship between the structure and performance. The review also addresses key challenges associated with VO2 as a cathode material, including dissolution, by-product formation, and limited ion diffusion kinetics. To overcome these issues, various optimization strategies are systematically discussed, such as ion/molecule pre-intercalation, composite material fabrication, defect engineering, and elemental doping. Finally, potential research directions and strategies to further enhance the performance and commercial viability of VO2-based cathodes are proposed.

Rechargeable aqueous zinc-ion batteries (ZIBs) are promising systems for energy storage due to their operational safety, low cost, and environmental friendliness. However, the development of suitable cathode materials is plagued by the sluggish dynamics of Zn2+ with strong electrostatic interaction. Herein, an Al3+-doped tremella-like layered Al0.15V2O5·1.01H2O (A-VOH) cathode material with a large pore diameter and high specific surface area is demonstrated to greatly boost electrochemical performance as ZIB cathodes. Resultant ZIBs with a 3 M Zn(CF3SO3)2 electrolyte deliver a high specific discharge capacity of 510.5 mAh g-1 (0.05 A g-1), and an excellent energy storage performance is well maintained with a specific capacity of 144 mAh g-1 (10 A g-1) even after ultralong 10,000 cycles. The decent electrochemical performance roots in the novel tremella-like structure and the interlayer of Al3+ ions and water molecules, which could improve the electrochemical reaction kinetics and structural long cycle stability. Furthermore, the assembled coin-type cells could power a light-emitting diode (LED) lamp for 2 days. We believed that the design philosophy of unique morphology with abundant active sites for Zn2+ storage will boost the development of competitive cathodes for high-performance aqueous batteries.

Accordion-like V10O24·12H2O was prepared via one-step reduction of commercial V2O5. Benefiting from the interlayer spacing, mixed valence, and superstructure, a superior performance was obtained for V10O24·12H2O as compared to that of V2O5.

… It is speculated that these irregular morphologies may be … nucleation, the absence of morphological control at the molecular … 2g–i show the morphological characterization of the …

The rapid depletion of lithium resources and the increasing demand for electrical energy storage have stimulated the pursuit of emerging electrochemical energy storage. Aqueous zinc ion batteries (ZIBs) are highly sought after for their low cost, high safety, and increased environmental compatibility. However, the search for suitable cathode materials is still tricky for a wide range of researchers. Vanadium oxides (VxOy), with their abundant vanadium valence, easily deformable V−O polyhedrons, and tunable chemical compositions, are of significant advantage in developing emerging materials. This work provides a detailed review of different VxOy for the application in aqueous ZIBs. The current problems and optimization strategies of VxOy cathode materials are systematically discussed. Finally, the current challenges and possible directions for future research of VxOy cathode materials in aqueous ZIBs are presented.

… cathode materials for AZIBs. The prepared PANI-VOH exhibits a 3D sponge-like morphology … Among V-based cathode materials, layered hydrated vanadium pentoxide (V 2 O 5 ·nH 2 O, …

… morphological evolution of the V2O5 cathode. As shown in Figure 6a, after the 5th charging (1.6V), the peaks assigned to V2O5 (PDF# 41-1426) and V2O5·nH2O (PDF #40-1296) can …

Vanadium oxides are excellent cathode materials with large storage capacities for aqueous zinc-ion batteries, but their further development has been hampered by their low electronic conductivity and slow Zn2+ diffusion. Here, an electrochemically induced phase transformation strategy is proposed to mitigate and overcome these barriers. In situ X-ray diffraction analysis confirms the complete transformation of tunnel-like structural V6O13 into layered V5O12·6H2O during the initial electrochemical charging process. Theoretical calculations reveal that the phase transformation is crucial to reducing the Zn2+ migration energy barrier and facilitating fast charge storage kinetics. The calculated band structures indicate that the bandgap of V5O12·6H2O (0.0006 eV) is lower than that of V6O13 (0.5010 eV), which enhanced the excitation of charge carriers to the conduction band, favoring electron transfer in redox reactions. As a result, the transformed V5O12·6H2O delivers a high capacity of 609 mA h g–1 at 0.1 A g–1, superior rate performance (300 mA h g–1 at 20 A g–1), fast-charging capability (<7 min charging for 465 mA h g–1), and excellent cycling stability with a reversible capacity of 346 mA h g–1 at 5 A g–1 after 5000 cycles.

Aqueous zinc-ion batteries (AZIBs) are considered to be highly promising electrochemical energy storage device due to their affordability, inherent safety, large zinc resources, and optimal specific capacity. Among various cathode materials, manganese dioxide (MnO2) stands out for its high voltage, environmental benignity, and theoretical specific capacity. This study systematically investigates the phase formation and structural parameters of α-MnO2, β-MnO2, and δ-MnO2 synthesized via hydrothermal method, employing Rietveld refinement. FTIR and Raman spectroscopy confirms Mn-O and O-H bond formation. BET analysis reveals surface areas, and pore size distribution is calculated with BJH method. High-resolution XPS spectra exhibit a spin energy split of ~ 11.9 eV for Mn 2p confirming the presence of MnO2. Electrochemical studies shows an initial discharge capacities of 230.5, 188.74 and 263.30 mAh g− 1 at 0.1 A g− 1 for α-MnO2, β-MnO2 and δ-MnO2. The EIS spectra revealed the capacitive behaviour and electrode reaction kinetics where a RcT value of 484.14, 327.6, 162.5 Ω for α-MnO2, β-MnO2 and δ-MnO2. These study give insights into relation of various properties of MnO2 with electrochemical performance and its viability in grid storage applications.

Abstract For manganese-based oxides to be used as one of the most promising aqueous zinc-ion batteries (ZIBs) cathode materials, improvements in cycling stability are required. In this work, manganese oxides (MnOx) hierarchical microspheres, including MnO, γ-MnO2 (MnO2), Mn2O3 and Mn3O4, are prepared, and their electrochemical performances are systematically investigated as cathode materials for aqueous ZIBs. The MnOx hierarchical structures can effectively shorten the diffusion pathway of Zn2+, tolerate the structural stress caused by Zn2+ insertion/extraction and restrain the self-aggregation of nanomaterials. Among MnOx, MnO hierarchical microspheres displays a high reversible capacity of 376.7 mAh g−1, good rate capability and excellent cycling stability with capacity retention of 99.37% over 1000 cycles. Finally, the zinc ion storage mechanism of MnO cathode is revealed. The results show that the remarkable electrochemical performance of MnO cathode is attributed to layered-type MnO2 structure formed during the initial few cycles, which is conducive to the insertion/extraction of zinc ions. This work is expected to deepen the understanding of the energy storage mechanism of MnO and helped to choose the ideal manganese-based cathode materials for aqueous ZIBs.

Manganese oxides are a promising cathode material for aqueous zinc-ion batteries (AZIBs), but thin-film configurations remain underexplored. This study investigates the electrochemical dynamics of 60 nm thin Mn3O4 thin films, fabricated via RF magnetron reactive sputtering. It addresses the highest reported capacity (25 mAh/g) in thin film form, stability over 500 cycles, effective performance across varying current rates, surpassing previous studies and challenges such as phase stability, and capacity fading over extended cycling, aiming to enhance uniformity, minimizing diffusion barriers for improved performance. EIS reveals Zn2+ diffusion coefficients of 1.503 × 10–7, 1.336 × 10–16, and 1.947 × 10–20 cm2/s in precycle, charged, and discharged states, respectively, highlighting evolving diffusion dynamics during cycling. Structural instability during discharge leads to a decline in diffusion performance, emphasizing the need for material and interfacial optimizations to enhance stability and mitigate degradation. These findings underscore the critical role of interfacial engineering and structural stability in maintaining high ion diffusion rates and minimizing morphological degradation during cycling. The present study explores the critical role of targeted engineering in unlocking their full potential for lightweight, miniaturized, high-performance microbatteries for energy storage applications.

… cathode material, or α-MnO2 more specifically. We show that Zn2+ insertion into the cathode is … in the electrolyte, the phase/morphology control and surface engineering of MnO2. In our …

Aqueous zinc ion batteries have attracted extensive concern as a promising candidate for large-scale energy storage because of their high theoretical specific capacity, low cost and inherent safety. However, the lacking of applicable cathode materials with outstanding electrochemical performance have severely hindered the further development of aqueous zinc ion batteries. Herein, we report a hierarchical accordion-like manganese oxide@carbon (MnO@C) hybrid with strong interaction heterointerface and comprehensively inquire into its electrochemical performance as cathode materials for aqueous zinc ion batteries. The unique hierarchical accordion-like layered structure coupling with strong interaction heterointerface between small MnO and carbon matrix efficaciously improve the ion/electron transfer process and enhance structure stability of the MnO@C hybrid. Benefitting from these unique advantages, the MnO@C hybrid bestows excellent specific capacity of 456 mAh g-1 at 50 mA g-1. Impressively, the MnO@C hybrid presents distinguished long-term cycling stability with fairly low decay rates of only 0.0079 % per cycle even over 2000 cycles at 2000 mA g-1. Moreover, comprehensive characterizations are executed to elucidate the mechanism involved. Therefore, this work affords a new idea for developing outstanding performance manganese-based cathode materials for aqueous zinc ion batteries.

… strategic design, construction, morphology, and the integration … matrices, and adjusting the morphology of the Mn2O3. Some … electrode materials and cathode catalysts for improved …

Recently, vanadium dioxide (VO2) has been recognized as one of the most prospective cathodes for aqueous zinc ion batteries (AZIBs) for its high reversible specific capacity; nevertheless, its Zn2+ diffusion kinetics and cycling stability have not yet met expectations. Herein, Mo ions are introduced into VO2 to optimize the intrinsic electronic structure and micromorphology of VO2, achieving significantly enhanced zinc-ion storage. It is found that the substitution of Mo for V narrows the band gap of VO2 and thus enhances the conductivity of the material, while VO2 nanorods are transformed into VO2 nanoflowers which are self-assembled from ultra-thin nanosheets after the introduction of Mo, exposing much more active sites to enhance the migration kinetics of Zn2+. Consequently, the Mo-substituted VO2 (0.5-Mo-VO2) exhibits excellent electrochemical properties, presenting a high initial capacity of 494.5 mAh/g at 0.5 A/g, excellent rate capability of 336 mA h g-1 at 10 A/g and brilliant cycling stability with the capacity retention of 82% over 2000 cycles at 10 A/g. This work provides significant guidance for the design of advanced cathodes for AZIBs by optimizing the electronic structure and tailoring morphology of V-based materials.

… Among them, vanadium-based materials not only have … or tunnel-like structure of vanadium-based materials as pillars (such … produce a type of ZIBs cathode material with potential …

Aqueous rechargeable batteries employing vanadium-based cathodes, including aqueous zinc-… In this background, Vanadium-based cathode materials, owing to their multivalent redox …

Aqueous zinc-ion batteries (AZIBs) are promising for energy storage due to their high safety, low cost, and environmental friendliness. Vanadium-based materials, including vanadium oxides, vanadium sulfides, vanadate, and vanadium carbon composites, have gained attention for their diverse crystal structures, multiple oxidation states, and high theoretical capacities. This review summarizes recent advances in vanadium-based cathodes, focusing on structural design and modification strategies, such as amorphous structures, defect engineering, conductive carbon matrices, and cation pre-intercalation to enhance Zn2+ storage. Vanadium oxides and vanadium sulfides offer unique ion diffusion advantages, while vanadate and vanadium carbon composites improve conductivity and stability. Vanadate is highlighted as a critical approach to reduce electrostatic repulsion and facilitate Zn2+ storage. Vanadium carbon composites (V-MOF derivations, vanadium oxides @ carbon, combined with graphene and conductive polymer) have unique advantages in terms of conductivity, ion diffusion, and structural stability. Emerging materials like VN, VOPO4 and V2CTx are also discussed. Future directions include multi-guest doping, anion pre-intercalation, and advanced carbon integration. This review aims to guide the development of high-performance AZIBs and inspire future research in this field.

MnO2 cathode materials have presented challenges due to their poor conductivity, unstable structure, and sluggish diffusion kinetics for aqueous zinc-ion batteries (AZIBs). In this study, a nanostructured MnOx cathode material was synthesized using an acid etching method, Which introduced abundant Mn(III) sites, resulting in the formation of numerous oxygen vacancies. Comprehensive characterizations revealed that these oxygen vacancies facilitated the reversible adsorption/desorption of Zn2+ ions and promoted efficient electron transfer. In addition, the designed mesoporous structure offered ample active sites and shortened the diffusion path for Zn2+ and H+ ions. Consequently, the nanosized MnOx cathode exhibited enhanced reaction kinetics, achieving a considerable reversible specific capacity of 388.7 mAh/g at 0.1 A/g and superior durability with 72.0% capacity retention over 2000 cycles at 3.0 A/g. The material delivered a maximum energy density of 639.7 Wh kg-1 at 159.94 W kg-1. Furthermore, a systematic analysis of the zinc storage mechanism was performed. This work demonstrates that engineering oxygen vacancies with nanostructure regulation provides valuable insights into optimizing MnO2 cathode materials for AZIBs.

The development of advanced cathode materials for zinc-ion batteries (ZIBs) is a critical step in building large-scale green energy conversion and storage systems in the future. Manganese dioxide is one of the most well-studied cathode materials for zinc-ion batteries due to its wide range of crystal forms, cost-effectiveness, and well-established synthesis processes. This review describes the recent research progress of manganese dioxide-based ZIBs, and the reaction mechanism, electrochemical performance, and challenges of manganese dioxide-based ZIBs materials are systematically introduced. Optimization strategies for high-performance manganese dioxide-based materials for ZIBs with different crystal forms, nanostructures, morphologies, and compositions are discussed. Finally, the current challenges and future research directions of manganese dioxide-based cathodes in ZIBs are envisaged.

… cathodes for AZIBs. In this Review, we will focus on an important subject related to layered and hydrated manganese- and vanadium-based cathodes … , nanostructured morphology, and …

… The hydrothermal method allows for precise control of nanostructures, making it ideal for synthesizing manganese oxides with high surface areas. The chemical precipitation method is …

Rechargeable aqueous zinc‐ion batteries (ZIBs) are promising candidates for advanced electrical energy storage systems owing to low cost, intrinsic safety, environmental benignity, and decent energy densities. Currently, significant research efforts are being made to develop high‐performance positive electrodes for ZIBs. Nevertheless, there are still many obstacles to be overcome in pursuit of the comprehensive performance of cathode materials, including specific capacity, structural stability, rate performance, and so forth. Many manganese‐based compounds have become the hotspots in the study of ZIB cathodes due to their advantages of natural abundance, less toxicity, and high operating voltage. Here, different energy storage mechanisms of various kinds of manganese‐based compounds are summarized. Electrochemical results of manganese‐based cathodes are compared and analyzed. Moreover, optimization strategies for addressing existing issues of these materials and improving ZIBs are discussed in detail.

Abstract In-situ self-transformation is proved to be an effective strategy to design high-performance cathodes for aqueous zinc-ion batteries (ZIBs). However, the inferior transformation efficiencies during phase transition limit its further application. Herein, a 3D spongy VO2-graphene (VO2-rG) precursor has been designed for achieving the ultra-efficient in-situ self-transformation process from VO2-rG into multifaceted V2O5·nH2O-graphene composite (VOH-rG). Benefiting from the highly conductive heterointerfaces, rich reaction sites and numerous ions diffusion channels of VO2-rG, almost 100% VO2 nanobelts are converted into VOH during the first charging with few side reactions, indicating a highly efficient transformation kinetics. This strategy enables structural modulation from micro-nano level to molecular level by integrating pre-inserted H2O molecules and constructing 3D porous heterogeneous architecture into the VOH-rG cathode simultaneously, leading to fast and enduring Zn2+ (de)intercalation kinetics. Consequently, the VOH-rG cathode exhibits high capacity of 466 mA h g−1 at 0.1 A g−1, superior rate performance (190 mA h g−1 even at 20 A g−1) and excellent cycling stability with 100% capacity retention over 5000 cycles. Moreover, the assembled VOH-rG//Zn flexible quasi-solid-state batteries also present impressive performance. Such an ultra-efficient in-situ self-transformation strategy would pave a new way to explore promising electrode materials for advanced energy storage.

Selecting the right cathode material is a key component to achieving high‐energy and long‐lifespan aqueous zinc‐ion batteries (AZIBs); however, the development of cathode materials still faces serious challenges due to the high polarization of Zn2+. In this work, MnV12O31·10H2O (MnVO) synthesized via a one‐step hydrothermal method is proposed as a promising cathode material for AZIBs. Because the stable layered structure and hieratical morphology of MnVO provide a large layer space for rapid ion transports, this material exhibits high specific capacity (433 mAh g−1 at 0.1 A g−1), an outstanding long‐term cyclability (5000 cycles at a current density of 3 A g−1), and an excellent energy density (454.65 Wh kg−1). To illustrate the intercalation mechanism, ex situ X‐Ray diffraction, Fourier transform infrared spectroscopy, and X‐ray photoelectron spectroscopy are adopted, uncovering an H+/Zn2+ dual‐cation co‐intercalation processes. In addition, density‐functional theory calculation analysis shows that MnVO has a delocalized electron cloud and the diffusion energy barrier of Zn2+ in MnVO is low, which promotes the Zn2+ transport and consequently improves the reversibility of the battery upon deep cycling. The key and enlightening insights are provided in the results for designing high‐performance vanadium‐oxide‐based cathode materials for AZIBs.

… morphology and phase composition for ammonium vanadate compounds synthesized via hydrothermal … peculiar rod-like morphology of NH 4 V 4 O 10 contribute to highly reversible …

… as the cathode in aqueous zinc-ion batteries (AZIBs), … electronic conductivity, slow Zn 2+ ion transport within the lattice, … incorporation on the structure, morphology, Zn 2+ storage kinetics…

… ZVOH is used as the cathode in zinc-ion batteries (ZIBs) with … as well as the morphological changes on the surface of the … In this paper, ZVOH was synthesized using a hydrothermal …

… We are the first to develop an α-MnSe-NR cathode synthesized by a facile hydrothermal method with lengths up to 100 nm … The morphological and structural evolution of the developed …

Vanadium oxide cathode materials with stable crystal structure and fast Zn2+ storage capabilities are extremely important to achieving outstanding electrochemical performance in aqueous zinc‐ion batteries. In this work, a one‐step hydrothermal method was used to manipulate the bimetallic ion intercalation into the interlayer of vanadium oxide. The pre‐intercalated Cu ions act as pillars to pin the vanadium oxide (V‐O) layers, establishing stabilized two‐dimensional channels for fast Zn2+ diffusion. The occupation of Mn ions between V‐O interlayer further expands the layer spacing and increases the concentration of oxygen defects (Od), which boosts the Zn2+ diffusion kinetics. As a result, as‐prepared Cu0.17Mn0.03V2O5−□·2.16H2O cathode shows outstanding Zn‐storage capabilities under room‐ and low‐temperature environments (e.g., 440.3 mAh g−1 at room temperature and 294.3 mAh g−1 at −60°C). Importantly, it shows a long cycling life and high capacity retention of 93.4% over 2500 cycles at 2 A g−1 at −60°C. Furthermore, the reversible intercalation chemistry mechanisms during discharging/charging processes were revealed via operando X‐ray powder diffraction and ex situ Raman characterizations. The strategy of a couple of 3d transition metal doping provides a solution for the development of superior room‐/low‐temperature vanadium‐based cathode materials.

… is promising cathode for aqueous zinc-ion batteries (AZIBs). … on carbon cloth (Al-NVO@CC) via a one-step hydrothermal … source changed the morphology of the carbon fiber surface …

ABSTRACT Zinc-ion batteries (ZIBs), in particular quasi-solid-state ZIBs, occupy a crucial position in the field of energy storage devices owing to the superiorities of abundant zinc reserve, low cost, high safety and high theoretical capacity of zinc anode. However, as divalent Zn2+ ions experience strong electrostatic interactions when intercalating into the cathode materials, which poses challenges to the structural stability and higher demand in Zn2+ ions diffusion kinetics of the cathode materials. Here, a microwave-assisted hydrothermal method is adopted to prepare pre-potassiated hydrated vanadium pentoxide (K0.52V2O5•0.29H2O, abbreviated as KHVO) cathode material, in which the potassium ions pre-inserted into the interlayers can act as “pillars” to stabilize the lamellar structure, and crystal water can act as “lubricant” to improve the diffusion efficiency of Zn2+ ions. Consequently, the KHVO displays high electrochemical properties with high capacity (∼ 300 mAh/g), superior rate capability (69 mAh/g at 5 A/g) and ultralong cycling performance (>1500 cycles at 2 A/g) in quasi-solid-state ZIBs. These superior Zn storage properties result from the large diffusion coefficient and highly stable and reversible Zn2+ (de)intercalation reaction of KHVO.

Vanadium-based cathode materials have attracted significant interest owing to their high theoretical capacities (>300 mA h g–1), versatile electrochemical ion insertions, and high valence states. However, their poor electrical conductivities and dissolution in electrolytes have hindered the development of grid energy storage systems. To address these issues, Cu2+ ion-doped V3O7·H2O (CuVO-2) cathode materials prepared via a one-step hydrothermal method were used to solve the aforementioned problems. The as-prepared CuVO-2 offered ample space for rapid ion transport, enabling a high reversible capacity of 444.8 mA h g–1 at 0.1 A g–1, excellent rechargeability of up to 5000 cycles at 5 A g–1 with a Coulombic efficiency (CE) of 84.4%, and an acceptable energy density of 302.65 W h kg–1. To better understand the storage mechanism of CuVO-2, several characterizations were conducted, including ex situ X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS), which helped elucidate the intercalation mechanism of the developed cathode materials. These findings offer valuable insights into the design of stable V-based cathode materials for next-generation aqueous zinc-ion batteries (AZIBs).