High-performance Aqueous Zinc-ion Research Articles

Facile and effective defect engineering strategy boosting ammonium vanadate nanoribbon for high performance aqueous zinc-ion batteries

Vanadium-based oxides have gained widespread attention as promising cathode materials for aqueous zinc-ion batteries (AZIBs) due to their abundant valences, high theoretical capacity and low cost. However, the intrinsic sluggish kinetics and unsatisfactory conductivity have severely hampered their further development. Herein, a facile and effective defect engineering strategy was developed at room temperature to prepare the defective (NH4)2V10O25·8H2O (d-NHVO) nanoribbon with plenty of oxygen vacancies. Owing to the introduction of oxygen vacancies, the d-NHVO nanoribbon possessed more active sites, excellent electronic conductivity and fast ion diffusion kinetics. Benefiting from these advantages, the d-NHVO nanoribbon as an aqueous zinc-ion battery cathode material exhibited superior specific capacity (512 mAh g−1 at 0.3 A g−1), excellent rate capability and long-term cycle performance. Simultaneously, the storage mechanism of the d-NHVO nanoribbon was clarified via comprehensive characterizations. Furthermore, the pouch battery based on the d-NHVO nanoribbon was fabricated and presented eminent flexibility and feasibility. This work provides a novel thought for simple and efficient development of high- performance vanadium-based oxides cathode materials for AZIBs.

Hierarchical spheroidal MOF-derived MnO@C as cathode components for high-performance aqueous zinc ion batteries

Aqueous zinc-ion batteries (AZIBs) have shown great potential as energy storage devices owing to their high energy density, low cost, and low toxicity. Typically, high performance AZIBs incorporate manganese-based cathode materials. Despite their advantages, these cathodes are limited by significant capacity fading and poor rate performance due to the dissolution and disproportionation of manganese. Herein, hierarchical spheroidal MnO@C structures were synthesized from Mn-based metal–organic frameworks, which benefit from a protective carbon layer to prevent manganese dissolution. The spheroidal MnO@C structures were incorporated onto a heterogeneous interface to act as a cathode material for AZIBs, which exhibited excellent cycling stability (160 mAh g−1 after 1000 cycles at 3.0 A g−1), good rate capability (165.9 mAh g−1 at 3.0 A g−1), and appreciable specific capacity (412.4 mAh g−1 at 0.1 A g−1) for AZIBs. Moreover, the Zn2+ storage mechanism in MnO@C was comprehensively investigated using ex-situ XRD and XPS studies. These results demonstrate that hierarchical spheroidal MnO@C is a potential cathode material for high-performing AZIBs.

Microfluidic-oriented assembly of Mn3O4@C/GFF cathode with multiscale synergistic structure for high-performance aqueous zinc-ion batteries

The electrochemical activity and long-term stability of cathodic materials, as well as active ion transport, are key factors for efficient energy storage in aqueous zinc-ion batteries (ZIBs). Here, a freestanding Mn3O4@C nanowire-implanted graphene-based fiber fabric (Mn3O4@C/GFF) cathode with a multiscale synergistic structure was fabricated using a facile microfluidic assembly method. In this architecture, Mn3O4 nanowires are hosted by a conductive carbon layer and then anchored in the interlayer of a self-assembled graphene-based fiber framework. The hierarchical structure enhances electrical conductivity and relieves ion leaching, thereby boosting the electrochemical activity and long-term stability of cathodic materials. Furthermore, the layer-by-layer assembled structure of the Mn3O4@C/GFF cathode provides ample available channels for active ion transport, accelerating the electrochemical kinetics. Consequently, the Mn3O4@C/GFF cathode exhibits enhanced electrochemical performance with a high capacity of 374.8 mAh g−1 at 0.2 A g−1 and ultralong cycle life (158.7 mAh g−1 retained over 5000 cycles at 2 A g−1). Therefore, this study provides a multiscale synergistic strategy for fabricating advanced cathodes for high-performance ZIBs.

A design of MnO-CNT@C3N4 cathodes for high-performance aqueous zinc-ion batteries

Manganese oxides have been regarded as one of the most promising candidates in rechargeable aqueous zinc ion batteries due to their high specific capacity, high operating voltage, low cost and no-toxicity. Nevertheless, the grievous dissolution of manganese and the sluggish Zn2+ ions diffusion kinetics deteriorate the long cycling stability and the rate performance. Herein, we propose a combination of hydrothermal and thermal treatment strategy to design a MnO-CNT@C3N4 composite cathode material where MnO cubes are coated by carbon nanotubes (CNTs) and C3N4. Owing to the enhanced conductivity by CNTs and the alleviation of the dissolution of Mn2+ from the active material by C3N4, the optimized MnO-CNT@C3N4 exhibits an excellent rate performance (101 mAh g−1 at a large current density of 3 A g−1) and a high capacity (209 mAh g−1 at a current density of 0.8 A g−1), which is much better than its MnO counterpart. The energy storge mechanism of MnO-CNT@C3N4 is confirmed to be the co-insertion of H+/Zn2+. The present work provides a viable strategy for the design of advanced cathodes for high-performance zinc ion batteries.

Recent Progress in Aqueous Zinc-Ion Batteries: From FundamentalScience to Structure Design.

Rechargeable aqueous zinc-ion batteries (ZIB) sparked a considerable surge of research attention in energy storage systems due to its environment benignity and superior electrochemical performance. Up to now, less efforts to delve into mechanisms of zinc metal anode and their electrochemical performance. Zn metal anodes sustain thorny issues with Zn dendrite growth, hydrogen evolution reaction, and Zn corrosion irreversible byproduct formation, which results in low coulomb efficiency (CE) and poor cycle ability of the battery. Herein, we reveal the fundamental understanding of the above issue, outline four step, including mass transfer, desolvation process, charge transfer and Zn cluster formation. It can be clearly seen from reported strategies to promote Zn anode stability that deals with one or more steps, thereby boosting the understanding of the issues of Zn anodes and benefiting the rational design to surmount the issue. We also sum up advanced materials and structure design such as the design of the anode surface and internal structure, electrolyte strategies, and multifunctional separators. Finally, possible tactics and future innovation direction for Zn-based batteries are proposed to achieve high performance aqueous Zinc-ion batteries.

High-performance aqueous zinc-ion hybrid capacitors based on 3D printed metal-organic framework cathodes

The zinc-ion hybrid capacitor is a promising energy storage device, but current overall capacity is limited by the capacitance of the carbon cathode. We produced a hierarchically porous, nitrogen-doped carbon cathode with good cycling and mechanical stability by 3D printing and pyrolysis of the zinc-based metal–organic framework ZIF-8. When incorporated into a zinc-ion hybrid capacitor, we achieved an areal capacitance of 16.9 F cm−2 and energy density of 7.23 mW h cm−2, outperforming zinc-ion hybrid capacitors based on conventional cathodes.

Enhanced H+ Storage of a MnO2 Cathode via a MnO2 Nanolayer Interphase Transformed from Manganese Phosphate.

The MnO2 cathode has attracted extensive attention in aqueous zinc ion battery research due to its environmental benignity, low cost, and high capacity. However, sluggish kinetics of hydrated zinc ion and manganese dissolution lead to insufficient rate and cycle performances. In this study, a manganese phosphate nanolayer synthesized in situ on a MnO2 cathode can be transformed into a δ-MnO2 nanolayer interphase after activation upon cycling, endowing the interphase with abundant interlayer water. As a result, the δ-MnO2 nanolayer interphase with the function of H+ topochemistry significantly enhances H+ (de)insertion in the MnO2 cathode, which leads to a kinetics conversion from Zn2+-dominated (de)insertion to H+-dominated (de)insertion, thus endowing the MnO2 cathode with superior rate and cycle performances (85.9% capacity retention after 1000 cycles at 10 A g-1). This strategy can be highly scalable for other manganese-based cathodes and provides an insight for developing high-performance aqueous zinc ion batteries.

Construction of novel polyaniline-intercalated hierarchical porous V2O5 nanobelts with enhanced diffusion kinetics and ultra-stable cyclability for aqueous zinc-ion batteries

Rechargeable aqueous zinc-ion batteries (ZIBs) have received considerable attention for large-scale energy storage applications due to the unique merits of high energy density, eco-friendliness and reliable safety. However, the development of high performance cathodes is still hampered by their inferior reversibility and sluggish Zn2+ diffusion kinetics, resulting in insufficient rate capability and poor cycling performances. Herein, we employed a feasible “two-in-one” strategy to intercalate conductive polymer (polyaniline, PANI) as pillar molecules into the V-MOF-derived hierarchical porous V2O5 (designated as PVO) and used as cathode for high-performance ZIBs. The high specific surface area and nanobelt-like porous structure endowed PVO with abundant accessible electrochemical active sites and shortened the electrons/ions transfer pathways, further delivering a high discharge capacity (489 mAh g−1 at 0.1 A g−1 and 97.2% capacity retention after 100 cycles). Meanwhile, the intercalation of PANI not only effectively expanded the Zn2+ diffusion channels, but also improved the structural stability during cycling as “interlayer pillars”. More importantly, the introduction of PANI could enhance the conductivity of the overall structure and weaken the electrostatic interaction between Zn2+ and PVO host, thereby suppressing the collapse of the layered structure. Accordingly, the obtained PVO cathode exhibited excellent rate capability (375 mAh g−1 at 5.0 A g−1) and satisfactory cycling stability (91.8% capacity retention after 2000 cycles at 8.0 A g−1). Moreover, the reversible Zn2+ storage mechanism was further investigated by kinetics analysis and DFT calculations. These ideal results provide key insights into the design of MOF-based cathode materials for high-performance aqueous zinc ion batteries.

Cation‐Anion Redox Active Organic Complex for High Performance Aqueous Zinc Ion Battery

Organic redox compounds are attractive cathode materials in aqueous zinc‐ion batteries owing to their low cost, environmental friendliness, multiple‐electron‐transfer reactions, and resource sustainability. However, the realized energy density is constrained by the limited capacity and low voltage. Herein, copper‐tetracyanoquinodimethane (CuTCNQ), an organic charge–transfer complex is evaluated as a zinc‐ion battery cathode owing to the good electron acceptation ability in the cyano groups that improves the voltage output. Through electrochemical activation, electrolyte optimization, and adoption of graphene‐based separator, CuTCNQ‐based aqueous zinc‐ion batteries deliver much improved rate performance and cycling stability with anti‐self‐discharge properties. The structural evolution of CuTCNQ during discharge/charge are investigated by ex situ Fourier transform infra‐red (FT‐IR) spectra, ex situ X‐ray photoelectron spectroscopy (XPS), and in situ ultraviolet visible spectroscopy (UV–vis), revealing reversible redox reactions in both cuprous cations (Cu+) and organic anions (TCNQx‐1), thus delivering a high voltage output of 1.0 V and excellent discharge capacity of 158 mAh g−1. The remarkable electrochemical performance in Zn//CuTCNQ is ascribed to the strong inductive effect of cyano groups in CuTCNQ that elevated the voltage output and the graphene‐modified separator that inhibited CuTCNQ dissolution and shuttle effect in aqueous electrolytes.

Ta4C3-Modulated MOF-Derived 3D Crosslinking Network of VO2(B)@Ta4C3 for High-Performance Aqueous Zinc Ion Batteries

A two-dimensional MXene (Ta4C3) was innovatively used herein to modulate the space group and electronic properties of vanadium oxides, and the MXene/metal-organic framework (MOF) derivative VO2(B)@Ta4C3 with 3D network cross-linking was prepared, which was then employed as a cathode to improve the performance of aqueous zinc ion batteries (ZIBs). A novel method combining HCl/LiF and hydrothermal treatments was used to etch Ta4AlC3 to obtain a large amount of accordion-like Ta4C3, and the V-MOF was then hydrothermally grown on the surface of the stripped Ta4C3 MXene. During the annealing process of V-MOF@Ta4C3, the addition of Ta4C3 MXene liberates the V-MOF from agglomerative stacking, allowing it to show additional active sites. More significantly, Ta4C3 prevents the V-MOF in the composite structure from converting into V2O5 of space group Pmmn but into VO2(B) of space group C2/m after annealing. A considerable advantage of VO2(B) for Zn2+ intercalation is provided by the negligible structural transformation during the intercalation process and the special tunnel transport channels, which have an enormous area (0.82 nm2 along the b axis). According to first-principles calculations, there is a strong interfacial interaction between VO2(B) and Ta4C3, which deliver remarkable electrochemical activity and kinetic performances for the storage of Zn2+. Therefore, the ZIBs prepared with the VO2(B)@Ta4C3 cathode material exhibit an ultra-high capacity of 437 mA h·g-1 at 0.1 A·g-1 while showing good cycle performance and dynamic performance. This study will offer a fresh approach and a reference for creating metal oxide/MXene composite structures.

Sodium-potassium co-doped layered manganese dioxide cathode material for high performance aqueous zinc-ion batteries

Manganese dioxide with high operating voltage and satisfactory energy density have been identified as the promising cathode materials for aqueous zinc-ion batteries (AZIBs). However, the structural instability of manganese-based materials during the (dis)charging process limits their further development. Herein, sodium-potassium co-doped layered K0.37Na0.18MnO2·xH2O (KNMOH) are synthesized by a liquid-phase synthesis method at room temperature. The co-doping of Na+ and K+ stabilizes the layered structure, widens the layer spacing and has the effect of electrostatic shielding to facilitate the (de)intercalation of Zn2+. Benefiting from the stable structure and nanoscale size, the flower-like KNMOH cathode maintained a high specific capacity of 239.1 mAh·g−1 after 700 cycles at 500 mA·g−1. Simultaneously, this work firstly reveals that the presence of K8(SO4)(SO3OH)6 suppressed the generation of Zn4SO4(OH)6·0.5H2O, resulting in more free Zn2+ and high reversibility. This co-doped design of bimetallic ions insertion enhances the electrochemical performance and provides a new idea for the improvement of the manganese-based cathode materials for AZIBs.

Potassium pre-intercalated manganese dioxide nanoflakes for high-performance aqueous zinc ion batteries

Potassium pre-intercalated manganese dioxide nanoflakes for high-performance aqueous zinc ion batteries

A Nature-Inspired Separator with Water-Confined and Kinetics-Boosted Effects for Sustainable and High-Utilization Zn Metal Batteries.

Uncontrollable dendrite growth and sluggish ion-transport kinetics are considered as the main obstacles for the further development of high-performance aqueous zinc ion batteries (AZIBs). Here, a nature-inspired separator (ZnHAP/BC) is developed to tackle these issues via the hybridization of the biomass-derived bacterial cellulose (BC) network and nano-hydroxyapatite particles (HAP). The as-prepared ZnHAP/BC separator not only regulates the desolvation process of the hydrated Zn2+ ions (Zn(H2 O)6 2+ ) by suppressing the water reactivity through the surface functional groups, alleviating the water-induced side-reactions, but also boosts the ion-transport kinetics and homogenize the Zn2+ flux, resulting in a fast and uniform Zn deposition. Remarkably, the Zn|Zn symmetric cell with ZnHAP/BC separator harvests a long-term stability over 1600h at 1mAcm-2 , 1mAhcm-2 and endures stable cycling over 1025 and 611h even at a high depth of discharge (DOD) of 50% and 80%, respectively. The Zn|V2 O5 full cell with a low negative/positive (N/P) capacity ratio of 2.7 achieves a superior capacity retention of 82% after 2500 cycles at 10Ag-1 . Furthermore, the Zn/HAP separator can be totally degraded within 2 weeks. This work develops a novel nature-derived separator and provides insights in constructing functional separators toward sustainable and advanced AZIBs.

Fabrication and morphological effect of waxberry-like carbon for high-performance aqueous zinc-ion electrochemical storage

Promoting and enhancing the transport rate of multivalent electrolyte ions in the pores of electrode is central for constructing high-performance electrochemical devices. Herein, waxberry-like porous carbon with nanosheets packaged by spherical carbon particles is produced by adjusting separation of hydrophilic and hydrophobic parts of carbon source precursors. The carbon particles maintain their original morphology after KOH activation at high temperature, forming tunable pores (pore volume: 0.9386 cm3 g−1) on the surface of stacked nanosheet layers. Benefiting from the synergistic effect of structural features, an interfacial transport of aqueous zinc ions within the carbon electrodes is achieved, endowing the assembled zinc-ion hybrid supercapacitors (ZHSCs) with excellent energy storage performances, including high capacity (122.3 mAh g−1 at 0.1 A g−1), high energy density (97.78 Wh kg−1), large power density (8000 W kg−1), and cycling stability up to 10,000 cycles with capacity retention of 98%. Moreover, the ZHSCs show superior low-temperature performance and operability (78.27 mAh g−1 at −30 °C and three-time cycling stability between −20 and 20 °C without performance degradation). This work presents a new prospect on design and development of aqueous rechargeable zinc-ion energy storage devices that are available for a range of environmental conditions.

Improved electrochemical performance of aqueous zinc-ion batteries with modified glass fiber separator by Ketjen Black

The development of aqueous zinc-ion batteries (AZIBs) with high capacity and high cycling stability has drawn increasing attention in recent years. Herein, a novel separator modification technology by spraying Ketjen black (KB) conductive carbon layer on the side of cathode is developed for improving the capacity and cycle stability of AZIBs. Benefiting from the KB separator, the Zn/MnO2 battery shows a high reversible specific capacity of 194.6 mAh g−1 at a current density of 2 A g−1 in a long-term cycle of 1500 cycles. In addition, the battery maintains 87% capacity retention after 6000 cycles at the current density 5 A g−1. The results indicate that the KB separator reduces the charge transfer impedance and improves the ion diffusion coefficient, showing excellent electrochemical kinetics. Meanwhile, the unique adsorption properties of KB separator reduce the attachment of by-products on the cathode surface. And the KB separator electrooxidizes Mn2+ ions on the surface to generate electrochemically active layered birnessite. Birnessite not only balances the capacity fading of the battery, but also improves the capacity of the battery, so that the battery has stable electrochemical performance. The method adapted in this work provides valuable insights for designing high performance aqueous zinc-ion secondary batteries.

Ni/Fe Bimetallic Ions Co-Doped Manganese Dioxide Cathode Materials for Aqueous Zinc-Ion Batteries

The slow diffusion dynamics hinder aqueous MnO2/Zn batteries’ further development. Here, a Ni/Fe bimetallic co-doped MnO2 (NFMO) cathode material was studied by density functional theory (DFT) calculation and experimental characterization techniques, such as cyclic voltammetry (CV), galvanostatic intermittent titration technique (GITT) and electrochemical impedance spectra (EIS). The results indicated that the energy band structure and electronic state of MnO2 were effectively optimized due to the simultaneous incorporation of strongly electronegative Ni and Fe ions. Consequently, the NFMO cathode material exhibited a faster charge transfer and ion diffusion dynamics than MnO2 (MO), thus, the assembled NFMO/Zn batteries delivered excellent rate performance (181 mA h g−1 at 3 A g−1). The bimetallic ions co-doping strategy provides new directions for the development of oxide cathode materials towards high-performance aqueous zinc-ion batteries.

High-performance Zn-ion batteries constructed byin situconversion of surface-oxidized vanadium nitride into Zn3(OH)2V2O7·2H2O with oxygen defects

Surface-oxidized vanadium nitride transforms into Zn3V2O7(OH)2-based materials with oxygen defects by electrochemical conversion, which act as cathodes for high performance aqueous zinc ion batteries.

High-performance aqueous zinc ion hybrid capacitors obtained by Na2SO4 additive and dense pore structure.

In this study, the electrochemical performance of zinc ion hybrid capacitors (ZICs) was improved by employing carbon-based materials and electrolyte together. First, we prepared pitch-based porous carbon HC-800 as the electrode material, which possessed a large specific surface area (3607 m2 g-1) and a dense pore structure. This provided abundant adsorption sites for zinc ions, and thus stored more charges. Subsequently, 0.5 M Na2SO4 was added to 1 M Zn(CF3SO3)2 electrolyte via the cationic additive strategy, and the adsorption energy of sodium and zinc ions on the zinc electrode was calculated. The results showed that sodium ions would preferentially be adsorbed on the surface of the zinc electrode, which would inhibit the growth of zinc dendrites, and thus prolong the service life of the zinc electrode. Finally, the presence of solvated zinc ions in the narrowly distributed pores of HC-800 was studied, and the results showed that Zn(H2O)62+ underwent a desolvation process, resulting in the removal of two water molecules to form a tetrahedral structure of Zn(H2O)42+, which made the central surface of the zinc ions closer to the surface of HC-800, and thus the more capacitance achieved. Furthermore, the uniform distribution of Zn(H2O)42+ in the dense and neat pores of HC-800, improved the space charge density. Consequently, the assembled ZIC exhibited a high capacity (242.25 mA h g-1 at 0.5 A g-1) and ultra-long cycle stability (capacity retention at 87% after 110 000 charge/discharge cycles at a high current density of 50 A g-1 and a coulombic efficiency of 100%) and an energy density of 186.1 W h kg-1 and power density of 41 004 W kg-1.

In situgrowth of amorphous vanadium oxide nanospheres on carbon cloth as free-standing cathodes used in high performance aqueous zinc-ion batteries

3D amorphous VOxmicrospheres werein situgrown on alkali-treated carbon cloth (VOxMSs@ACC) as cathodes for AZIBs. VOxMSs@ACC cathodes show excellent specific capacity and cycling performance due to rich active sites and fast ion transport rates.

Research Status and Optimization Methods of Zinc Ion Battery

Up against the energy shortage and aggravating environmental pollution, it is extremely urgent to develop renewable clean energy. With efficient energy storage and energy conversion, electrochemical energy storage is the key direction for the development of energy storage technology in the future. Besides, aqueous zinc ion battery has attracted researchers because of its low cost and high theoretical specific capacity. Cathode materials for aqueous zinc ion batteries are roughly divided into manganese-based compounds, vanadium-based compounds, Prussian blue analogues, etc, which usually use zinc metal as an anode. Electrolytes include solid hydrogel electrolytes and liquid ion electrolytes. However, some problems exist in cathode materials, such as elements dissolution and low discharge voltage, while anode materials have problems in zinc dendrite growth and side reactions, and water decomposition occurs in electrolytes. In recent years, researchers have devoted themselves to optimizing aqueous zinc ion batteries in different ways, so as to obtain their high performance. In this paper, the general situation of zinc ion battery is introduced at first, and then the research status is emphatically expounded from the perspectives of problems existing in cathode materials, anode materials, electrolyte, and their optimization methods, which provides references for developing high-performance aqueous zinc ion battery.