Cathode Material For Aqueous Zinc-ion Batteries Research Articles

Elucidating the diffusion and interaction mechanisms of Zn2+ and H+ in MnO2 for aqueous zinc-ion batteries: A DFT study

MnO2 is a promising cathode material for aqueous zinc-ion batteries (AZIBs) with potential applications in large-scale energy storage systems. However, its practical use is hindered by poor cyclic stability and slow diffusion kinetics. Despite considerable efforts, success has been limited due to an unclear understanding of the intrinsic properties of Zn2⁺ and proton (H⁺) insertion into MnO2. This study investigates the predominant phases of MnO2—α, β, δ, and γ—and elucidates their reaction mechanisms using first-principles computational methods based on density functional theory (DFT). Our research reveals that H⁺ ions exhibit a higher initial insertion voltage compared to Zn2⁺ ions, but their diffusion in MnO2 is significantly impeded by strong interactions with oxygen. Additionally, H⁺ insertion partially obstructs Zn2⁺ ion migration. Furthermore, the insertion of Zn2⁺/H⁺ and the adsorption of H⁺ on the MnO2 surface are intricately linked to the dissolution process of manganese. This work significantly enhances our fundamental understanding of MnO2 as a cathode material for AZIBs.

Dual-Ion-Doped Hydrated Vanadium Oxides Nanowires As Cathode Materials for High-Rate Aqueous Zinc Ion Batteries

Due to environmental-friendliness, high safety and stability, high theoretical capacity as well as low cost, aqueous zinc ion batteries (AZIBs) are budding as attractive alternatives for large-scale energy storage applications. However, the lack of suitable positive electrode materials becomes the main issue for AZIBs to pursue high energy density and excellent rate capability. Herein, the dual-ion-doped hydrated vanadium oxide nanowires (VOH) are synthesized through hydrothermal method, which is suitable to be cathode materials for AZIBs. Through metal ions and crystal water pre-intercalation, the interlayer spacing of (001) becomes larger, which is proposed to have better capability to accommodate Zn2+. Moreover, the pre-intercalated metal ions can serve as structural pillars between layers, providing excellent stability during discharging/charging process. In this study, the novel dual-ion-doped VOH exhibits more than 420 mA h g−1 at 0.1 A g−1 as well as more than 260 mA h g−1 at 5 A g−1. In addition, it can retain more than 80% capacity after 500 cycles at 5 A g−1. The energy storage mechanism of dual-ion-doped VOH is revealed via operando x-ray absorption near edge spectroscopy. This study implies that this dual-ion-doped VOH nanowires can serve as suitable positive electrode materials for high-performance aqueous zinc ion batteries.

Polyaniline-modified amorphous tin-based Prussian blue analogue as cathodes for long-life aqueous zinc ion batteries

Prussian blue analogs (PBAs) have emerged in the field of aqueous zinc ion batteries (AZIBs) owing to their simple synthesis method and three-dimensional open framework structure. Although PBAs have high redox potentials, the unsatisfactory specific capacity and poor electrical conductivity limit their development to some extent. In this work, amorphous tin hexacyanoferrate (SnHCF) and polyaniline (PANI) were combined to form SnHCF/PANI composite. The synergistic effect of the amorphous structure of SnHCF and PANI with good conductivity makes the SnHCF/PANI electrode exhibit excellent redox activity and achieve rapid ion/electron transfer. When used as a cathode in AZIBs, the SnHCF/PANI provides a high specific capacity (136.8 mAh g−1 at 0.5 A g−1) and excellent cycling stability (a discharge specific capacity of 54.3 mAh g−1 after 2500 cycles at 2 A g−1). This work offers a new idea for the development of PBAs-based composites as cathode materials for AZIBs.

In situ growth of Mn3O4 nanoparticles on accordion-like Ti3C2Tx MXene for advanced aqueous Zn-Ion batteries

Manganese-based cathodes are competitive candidates for state-of-the-art aqueous zinc-ion batteries (AZIBs) because of their easy preparation method, sufficient nature reserve, and environmental friendliness. However, their poor cycle stability and low rate performance have prevented them from practical applications. In this study, Mn3O4 nanoparticles were formed in situ on the surface and between the interlayers of Ti3C2Tx MXene, which was pretreated by the intercalation of K+ ions. Ti3C2Tx MXene not only provides abundant active sites and high conductivity but also hinders the structural damage of Mn3O4 during charging and discharging. Benefiting from the well-designed K-Ti3C2@Mn3O4 structure, the battery equipped with the K-Ti3C2@Mn3O4 cathode achieved a maximum specific capacity of 312 mAh/g at a current density of 0.3 A/g and carried a specific capacity of approximately 120 mAh/g at a current density of 1 A/g, which remained stable for approximately 500 cycles. The performance surpasses that of most reported Mn3O4-based cathodes. This study pioneers a new approach for building better cathode materials for AZIBs.

Electropolymerization of a Carbonyl-Modified Dihydropyrazine Derivative for Aqueous Zinc Batteries with Ultrahigh Cycling Stability.

The design of aqueous zinc-ion batteries (ZIBs) that have high specific capacity and long-term stability is essential for future large-scale energy storage systems. Cathode materials with extended π-conjugation and abundant active sites are desirable to enhance the charge storage performance and the cycling stability of the aqueous ZIB. Based on this concept, 6,9-dihydropyrazino[2,3-g]quinoxaline-2,3,7,8(1H,4H)-tetrone was chosen as the monomer to be electropolymerized onto carbon cloth (PDHPQ-Tetrone/CC). When used as the cathode material for aqueous ZIBs, an exceptional cycling life (>20,000 cycles) at a current density of 10 A g-1 was achieved, with the specific capacity maintained at 82.8% and with the Coulombic efficiency at around 100% throughout cycling. At the charge-discharge current density of 0.1 A g-1, the ZIB with PDHPQ-Tetrone/CC achieved a high specific capacity of 248 mAh g-1. Kinetic analyses showed that both surface-capacitive-controlled processes and semi-infinite diffusion-controlled processes contribute to the stored charge. The charge storage mechanism was investigated with ex situ characterizations and involves the redox processes of carbonyl/hydroxyl and amino/imino groups coupled with insertion and extraction of both Zn2+ and H+.

Heterostructure Engineering of NiCo-LDHs for Enhanced Energy Storage Performance in Aqueous Zinc-Ion Batteries.

Aqueous zinc-ion batteries (AZIBs) are considered a promising device for next-generation energy storage due to their high safety and low cost. However, developing high-performance cathodes that can be matched with zinc metal anodes remains a challenge in unlocking the full potential of AZIBs. In this study, a typical transition metal layered double hydroxides (NiCo-LDHs) can be in situ reconstructed to NiCo-LDHs/Ni(Co)OOH heterostructure using an electrochemical cycling activation (ECA) method, serving as a novel cathode material for AZIBs. The optimized ECA-NiCo-LDHs cathode demonstrates a high capacity of 181.5 mAh g-1 at 1 A g-1 and retains 75% of initial capacity after 700 cycles at 5 A g-1. The abundant heterointerfaces of the NiCo-LDHs/Ni(Co)OOH material can activate additional active sites for zinc-ion storage and accelerate ion diffusion. Theoretical calculations also suggest the heterostructure can boost charge transfer and regulate ion-adsorption capability, thereby improving the electrochemical performance. Additionally, the flexible AZIBs device exhibits good service performance. This study on interface engineering introduces a new possibility for utilizing LDHs in AZIBs and offers a novel strategy for designing electrode materials.

Molecular Connectors Boosting the Performance of MoS2 Cathodes in Zinc-Ion Batteries.

Zinc-ion batteries (ZIBs) are promising energy storage systems due to high energy density, low-cost, and abundant availability of zinc as a raw material. However, the greatest challenge in ZIBs research is lack of suitable cathode materials that can reversibly intercalate Zn2+ ions. 2D layered materials, especially MoS2-based, attract tremendous interest due to large surface area and ability to intercalate/deintercalate ions. Unfortunately, pristine MoS2 obtained by traditional protocols such as chemical exfoliation or hydrothermal/solvothermal methods exhibits limited electronic conductivity and poor chemical stability upon charge/discharge cycling. Here, a novel molecular strategy to boost the electrochemical performance of MoS2 cathode materials for aqueous ZIBs is reported. The use of dithiolated conjugated molecular pillars, that is, 4,4'-biphenyldithiols, enables to heal defects and crosslink the MoS2 nanosheets, yielding covalently bridged networks (MoS2-SH2) with improved ionic and electronic conductivity and electrochemical performance. In particular, MoS2-SH2 electrodes display high specific capacity of 271.3 mAh g-1 at 0.1 A g-1, high energy density of 279Whkg-1, and high power density of 12.3 kW kg-1. With its outstanding rate capability (capacity of 148.1 mAh g-1 at 10 A g-1) and stability (capacity of 179 mAh g-1 after 1000 cycles), MoS2-SH2 electrodes outperform other MoS2-based electrodes in ZIBs.

Electrochemically inducing V2O5·nH2O nanoarrays vertically growth on VSx microrods for highly stable zinc ion battery cathode

The lack of suitable cathode materials greatly limits the potential applications of rechargeable aqueous zinc ion batteries (ZIBs), despite their great promise in terms of high safety, high energy density, and low cost. One promising cathode material is VOOH, which possesses high specific capacity and fast Zn2+ transport channels after a phase transition to V2O5·nH2O during electrochemical cycling. However, its susceptibility to structural disintegration and aggregation during charging and discharging leads to severe capacity decay. To address this issue, we construct a composite consisting of VOOH particles and VSx microrods by a one-step hydrothermal method using a vanadium-based metal-organic framework (MIL-88B(V)) as a sacrificial template. The VOOH particles undergo electrochemical activation and transform into V2O5·nH2O nanoarrays that vertically grow on the VSx microrods. This unique nano-composite effectively maintains the morphology of nanoarrays in electrochemical cycling, resulting in a significant enhancement of rate performance and long-term cycling stability. Moreover, the VSx itself provides considerable capacity and its high conductivity improves the rate performance of the composite. Consequently, the VOOH/VSx nanocomposite exhibits a superior capacity of 364 mA h g−1 at 0.2 A g−1 after activation. Notably, it maintains remarkable capacity retention of 99.6% after 700 cycles, even at a high current density of 10 A g−1. Based on these findings, we believe that the VOOH/VSx composite holds great promise as a cathode material for aqueous ZIBs.

Manganese-based MOF interconnected carbon nanotubes as a high-performance cathode for rechargeable aqueous zinc-ion batteries

Aqueous zinc-ion batteries (ZIBs) have attracted extensive attention due to their low cost, environmental friendliness, and high volumetric specific capacity. However, the design of cathode materials with high performance for ZIBs is quite limited. In this paper, a kind of manganese-based metal-organic framework/carbon nanotubes (Mn-MOF/CNT) composite is prepared as the cathode material for ZIBs via a one-pot in situ solvothermal method. Particularly, the assembled Mn-MOF/CNT//Zn battery exhibits high specific capacity (260 mAh g−1 at 50 mA g−1) and excellent capacity retention (approximately 100 %) after 900 cycles at 1000 mA g−1. This significant electrochemical performance is attributed to the high porosity and the high conductivity of Mn-MOF/CNT, as well as the Mn2+ electrolyte additive. This work renders a new sight to design high-performance MOF-based cathode materials for aqueous ZIBs.

Construction of 2D sandwich-like Na2V6O16·3H2O@MXene heterostructure for advanced aqueous zinc ion batteries

Aqueous zinc ion batteries (AZIBs) have attained enormous attention in the last few years. The cathode materials of aqueous zinc ion batteries play a vital effect in their electrochemical and battery properties. In this manuscript, Sandwich-like MXene@Na2V6O16·3H2O (NVO@MXene) heterostructure was successfully prepared by the combination and cooperation of the layer lattice structure of Na2V6O16·3H2O and the high conductivity of MXene. When used as the cathode material for AZIBs, NVO@MXene demonstrates preeminent rate capability and excellent reversible capacity of 175 mAh/g after 3000 cycles at 5 A/g with a retention rate of 88.9 % of initial discharge capacity. The outstanding battery performance can be attributed to the MXene layers with high conductivity for accelerating the ion diffusion rate and reducing the agglomeration of Na2V6O16·3H2O nanowires during the (dis)charge process. Meanwhile, the stable layered structure of Na16V6O6·3H2O with wide interlamellar spacing (d = 7.9 Å) is also favorable for the s fast intercalation/deintercalation of Zn2+. Finally, ex-situ X-ray diffraction and X-ray photoelectron spectroscopy were applied to study and reveal the energy storage mechanism of this novel material for aqueous zinc ion batteries.

Influence of separator and bimetallic doping on Zn2+ ion storage properties of Prussian blue analogues for aqueous zinc-ion batteries

Prussian blue analogues (PBA) have been gaining attention as cathode materials for Aqueous zinc-ion batteries (AZIBs) owing to their 3D open framework structure; however, they suffer from low specific capacity, fast degradation, and poor cycling stability. In this study, we report Co–Ni co-doped PBA, with different Co and Ni ratios with high purity and crystallinity as cathode materials for AZIBs. Moreover, different low-cost porous water-based separators are proposed in conjunction with Co–Ni co-doped PBA cathodes. The studies on Zn||Zn symmetric cell show that nitrocellulose membrane (NC) separator can operate over 2000 h with lower hysteresis voltage of 90 mV and considerably decreases the dendrite grown on the Zn-metal surface due to the uniform pore size distribution. Benefiting from the synergetic effect of bimetallic doping and Zn dendrite inhibition ability from NC separator, the aqueous K1.9Co0.67Ni0.33[Fe(CN)6].1.7H2O||Zn cell is able to display excellent cycling performance of 5000 cycles at 1 A g−1 with a maximum capacity retention of 84 %. This research not only demonstrates the considerable effect of bimetallic doping on the Zn storage performance of PBA cathodes, but it also discloses the influence of separator on the zinc striping/plating process, which will provide insights into the development of high-performance AZIBs.

Polypyrrole Film Decorated Manganese Oxide Electrode Materials for High-Efficient Aqueous Zinc Ion Battery

Aqueous zinc-ion batteries (AZIBs) have raised wide concern as a new generation energy storage device due to their high capacity, low cost, and environmental friendliness. It is a crucial step to develop the ideal cathode materials that match well with the Zn anode. In this work, we report polypyrrole-(PPy)-encapsulated MnO2 nanowires as cathode materials for AZIBs. The assembled Zn//MnO2@PPy batteries deliver a reversible capacity of 385.7 mAh g−1 at a current density of 0.1 A g−1. Also, they possess an energy density of 192 Wh kg−1 at a power density of 50 W kg−1. The cells show long-term cycling stability, with a retention rate of 96% after 1000 cycles. The outstanding electrochemical performance indicates their potential applications in large-scale energy storage.

Defect-engineered composite with ammonium vanadate and 1T-MoS2 for superior aqueous zinc-ion battery applications

Aqueous zinc-ion batteries (AZIBs) are competitive energy-storage systems owing to their high ionic conductivity, safety, low cost, and eco-friendliness. Vanadium-based oxides have gained research interest as cathode materials for AZIBs because of their high capacities derived from their multivalent states and layered structures. However, vanadium-based oxides continue to exhibit poor performance as electrodes owing to critical issues, such as structural collapse, cation trapping, and poor electrical conductivity, which limit their practical application. Defect-engineered composite cathode materials consisting of (NH4)2V6O16·1.5H2O (NVO) nanorods and metallic 1T-MoS2 nanosheets were fabricated using a sonochemical method. NH4+ and H2O were co-intercalated into the NVO interlayer and served as pillars for stabilizing the layered structure. The 1T-MoS2 nanosheets promote fast charge transfer by providing conductive networks to the NVO. Furthermore, the oxygen defects in the NVO lattice weaken the electrostatic attraction between the inserted Zn2+ cations and the lattice oxygen layers, facilitating reversible Zn2+ (de)intercalation during charging–discharging. Consequently, the Od-NVO/Oi-MoS2 electrode exhibited a high capacity of 370.5 mAh/g at a current density of 0.2 A/g. In addition, it exhibited a high capacity of 141 mAh/g and maintained 92.5% of its initial capacity after 2000 cycles at 10 A/g.

Synthesis and electrochemical properties of hydrangea‐like (NH4)2V4O9/V5O12·6H2O cathode for zinc‐ion battery

AbstractEnergy density, power density, as well as the cost of aqueous zinc‐ion batteries (AZIBs), are largely determined by the cathode material. Among the various cathodic candidates, vanadium‐based materials with various oxidation states of vanadium cations and open frameworks have emerged as highly promising options. In this work, a heterogeneous with hydrangea‐like (NH4)2V4O9/V5O12·6H2O as cathode materials for AZIBs. The hydrogen bonds formed by NH4+ of (NH4)2V4O9, in conjunction with the lattice water in V5O12·6H2O, sufficiently strengthen the cohesion of the layered structure and expand the interlayer space. As a result, accelerating the diffusion of Zn2+ ultimately leads to an enhanced overall discharge capacity. Remarkably, the hydrangea‐like (NH4)2V4O9/V5O12·6H2O electrode at a current density of 100 mA g−1 shows a high reversible capacity of 209 mAh g−1 after 150 cycles and higher rate capability (172 mAh g−1 at 500 mA g−1). The outstanding electrochemical performance can be attributed to the unique structure of the cathode material and accelerated diffusion coefficient of Zn2+.

A Sulfur Heterocyclic Quinone Cathode TowardsHigh-Rate and Long-Cycle Aqueous Zn-Organic Batteries.

Organic materials have attracted much attention in aqueous zinc-ion batteries (AZIBs) due to their sustainability and structure-designable, but their further development is hindered by the high solubility, poor conductivity, and low utilization of active groups, resulting in poor cycling stability, terrible rate capability, and low capacity. In order to solve these three major obstacles, a novel organic host, benzo[b]naphtho[2',3':5,6][1,4]dithiino[2,3-i]thianthrene-5,7,9,14,16,18-hexone (BNDTH), with abundant electroactive groups and stable extended π-conjugated structure is synthesized and composited with reduced graphene oxide (RGO) through a solvent exchange composition method to act as the cathode material for AZIBs. The well-designed BNDTH/RGO composite exhibits a high capacity of 296mAhg-1 (nearly a full utilization of the active groups), superior rate capability of 120mAhg-1 , and a long lifetime of 58000 cycles with a capacity retention of 65% at 10Ag-1 . Such excellent performance can be attributed to the ingenious structural design of the active molecule, as well as the unique solvent exchange composition strategy that enables effective dispersion of excess charge on the active molecule during discharge/charge process. This work provides important insights for the rational design of organic cathode materials and has significant guidance for realizing ideal high performance in AZIBs.

Bi2S3/rGO nanocomposites with covalent heterojunctions as a high-performance aqueous zinc ion battery material

Bismuth(III) sulfide (Bi2S3) is a promising cathode material for aqueous zinc ion batteries (ZIBs), yet suffers from serious capacity issues due to its poor electrical conductivity and microstructural degradations. In this work, Bi2S3 anchored on reduced graphene oxide (rGO) is prepared through hydrothermal reaction and is used as cathode material for aqueous ZIBs. Raman and XPS characterizations confirmed that the oxygen bridge in Bi–O–C heterostructures is successfully created during the hydrothermal synthesis. These oxygen bridges are energy favourable in the Bi2S3/rGO composite materials and serve as the electron transfer channels for rapid charge compensation during Zn2+ incorporation/extraction. Rotating ring–disc electrode (RRDE) measurements demonstrate improved electrochemical stability of the Bi2S3/rGO composite material compared to pristine Bi2S3. As a result of these improved characteristics, Bi2S3/rGO composite shows notably better rate performance and cycling stability than unsupported Bi2S3. Ex-situ X-ray diffraction and XPS characterizations indicate that Zn2+ undergoes a reversible conversion reaction with Bi2S3 to form ZnS/Bi0, rather than being intercalated into Bi2S3 crystal interlayers. The rGO substrate forms chemical bonds with bismuth in the composite material, and the strongly anchored bismuth on the rGO through a Bi–O–C bridge enables a highly reversible conversion reaction. As a result, the Bi2S3/rGO composite with 8 wt% rGO can deliver a reversible capacity of ∼186 mAh g−1 at the current density of 500 mA g−1 after 150 cycles, showing high promise as Zn-ion battery material.

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.

π-Conjugated N-heterocyclic compound with redox-active quinone and pyrazine moieties as a high-capacity organic cathode for aqueous zinc-ion batteries

Organic cathode materials have been widely used for aqueous zinc-ion batteries (ZIBs) due to their designable molecular structures and diverse redox groups. However, there are still many challenges that need to be overcome, such as limited specific capacity and utilization, inadequate electrical conductivity, unsatisfactory cycle durability and unclear charge storage mechanism. Herein, we report a π-conjugated N-heterocyclic compound containing dual-redox active groups (i.e. quinone and pyrazine), benzo[b]phenazine-6,11-dione (BPD), which are employed as a cathode material in aqueous ZIBs. The BPD cathode shows a high capacity of up to 429 mAh g−1 at 0.05 A g−1, 100 % capacity utilization and excellent cycling performance upon 10,000 cycles. The aqueous ZIB full cell with the BPD cathode delivers an energy density of 276 Wh kg−1, higher than the most previously reported organic cathode materials. Moreover, ex-situ characterizations, electrochemical experiments, and theoretical calculations, clearly illustrate that H+ and Zn2+ are co-inserted during the charge/discharge process. The high utilization and stability of BPD cathode is due to the high insolubility of both BPD and its discharge products. This work provides a reasonable strategy and unique perspective for the design and synthesis of novel high-performance organic cathode materials for aqueous ZIBs.

How About Vanadium-Based Compounds as Cathode Materials for Aqueous Zinc Ion Batteries?

Aqueous zinc-ion batteries (AZIBs) stand out among many monovalent/multivalent metal-ion batteries as promising new energy storage devices because of their good safety, low cost, and environmental friendliness. Nevertheless, there are still many great challenges to exploring new-type cathode materials that are suitable for Zn2+ intercalation. Vanadium-based compounds with various structures, large layer spacing, and different oxidation states are considered suitable cathode candidates for AZIBs. Herein, the research advances in vanadium-based compounds in recent years are systematically reviewed. The preparation methods, crystal structures, electrochemical performances, and energy storage mechanisms of vanadium-based compounds (e.g., vanadium phosphates, vanadium oxides, vanadates, vanadium sulfides, and vanadium nitrides) are mainly introduced. Finally, the limitations and development prospects of vanadium-based compounds are pointed out. Vanadium-based compounds as cathode materials for AZIBs arehoped to flourish in the coming years and attract more and more researchers' attention.

Unraveling Factors Affecting Performance of Quinone‐based Polymer Cathode in Aqueous Zinc‐Ion Battery

AbstractOrganic cathode materials for aqueous rechargeable Zinc‐ion batteries (ZIBs) include a large variety of aromatic molecules with redox‐activity, and such polymer molecules vary largely in terms of specific capacity, discharge voltage plateau, and cycling stability. Here, three different quinone polymers are prepared by electropolymerizing dihydroxynaphthalene (DHN) isomers of 1,5‐DHN, 1,6‐DHN, and 1,7‐DHN, respectively, and their energy storage performances in aqueous ZIBs are compared. Among the three cathode materials, the poly(1,6‐DHN) cathode shows the best performance in specific capacity and cycling stability. The Zn||poly(1,6‐DHN) cell shows a high areal capacity of 1.4 mAh cm−2 and a high capacity retention of 90 % after 5000 cycles. By combing experiment with computation, the HOMO level of the polymer molecule is found to play a key role behind the specific capacity. Using the poly(1,7‐DHN) cathode that suffers from faster capacity decay in the cycling process, our investigation suggests that residual ions stuck between molecular chains in the insertion/deinsertion process account for the capacity loss. This study provides a further understanding of organic cathode materials for aqueous ZIBs.