Cathode Materials For Zinc-ion Batteries Research Articles

A Novel Ni-doped ZnMn2O4/Mn2O3 nanocomposite synthesized by pulsed potential as superior zinc ion battery cathode material

The research and development of suitable cathode materials for Zn2+ storage is crucial to meet the large-scale energy storage application of zinc-ion batteries (ZIBs). However, manganese-based oxide cathodes, the most-studied category of cathode materials, suffer from capacity decline and weak electrical conductivity. Herein, Ni-doped ZnMn2O4/Mn2O3 nanocomposite has been synthesized using pulsed potential electrodeposition technique and then applied as cathode material for ZIBs. The Ni2+ doping effectively boosts the electrical conductivity and electrochemical performance of electrodes. Furthermore, simultaneous production of ZnMn2O4 /Mn2O3 nanocomposite as a two-phase compound and incorporation of Ni2+ in crystal structure leads to an improvement in reversibility and cyclability of Ni-doped ZnMn2O4/Mn2O3 nanocomposite. Moreover, the Ni-doped ZnMn2O4/Mn2O3 nanocomposite presents a specific capacity of 235.10 mAh g−1 (0.2 A g−1), higher than Undoped nanocomposite (215 mAh g−1). Besides, the Ni-doped ZnMn2O4/Mn2O3 nanocomposite shows superior electrochemical performance, with a reversible capacity of 114.67 mAh g−1 and capacity retention of 91.32%, obtained after 3000 cycles at 2 A g−1, while the Undoped -ZnMn2O4/Mn2O3 nanocomposite possesses the capacity of 61.85 mAh g−1 with 64.54% capacity retention at the same condition. The obtained results suggest that the synergistic effect of doping and two-phase compound synthesis provide new features for the practical application of ZIBs.

Exploring Cathode Materials for Zn-Ion Batteries: A First-Principles Investigation

Aqueous zinc-ion batteries (ZIBs) are a promising technique for large-scale energy storage, however, the large ionic potential of Zn2+ ions leads to slow diffusion kinetics of Zn2+ ions in cathode hosts. To address this issue, we predicted two vanadium-based compounds for potential applications as cathode materials for ZIBs through the evolutionary algorithm. The dynamic, mechanical, and thermodynamic stabilities of the newly discovered ZnVO3 polymorphs were confirmed by ab initio calculations. CI-NEB results show impressively low Zn2+-ion migration barriers of 0.44 and 0.40 eV for the predicted P2/c and P21/c polymorphs, respectively. Furthermore, the P21/c-structured ZnVO3 exhibits a small band gap of 1.62 eV, a high voltage plateau of 1.16 V, and a trivial volume change upon charging, which may suggest excellent rate performance and a long cycle life when functioning as a cathode material for ZIBs. The work may provide fundamental guidance for the design and development of electrode materials featuring intrinsic fast Zn2+ ion transportation.

The Promotion of Research Progress of Zinc Manganate Cathode Materials for Zinc-Ion Batteries by Characterization and Analysis Technology.

Zinc-ion batteries (ZIBs) have recently attracted great interest and are regarded as a promising energy storage device due to their low cost, environmental friendliness, and superior safety. However, the development of suitable Zn-ion intercalation cathode materials remains a great challenge, resulting in unsatisfactory ZIBs that cannot meet commercial demands. Considering that spinel-type LiMn2O4 has been shown to be a successful Li intercalation host, spinel-like ZnMn2O4 (ZMO) is expected to be a good candidate for ZIBs cathodes. This paper first introduces the zinc storage mechanism of ZMO and then reviews the promotion of research progress in improving the interlayer spacing, structural stability, and diffusivity of ZMO, including the introduction of different intercalated ions, introduction of defects, and design of different morphologies and in combination with other materials. The development status and future research directions of ZMO-based ZIBs characterization and analysis techniques are summarized.

Nitrogen-doped carbon/V2O3 nanorod composites as cathode material for high-performance aqueous Zn-ion battery

At present, the main challenge facing the aqueous zinc ion batteries (ZIBs) system is to find a kind of cathode material with high stability and large capacity. In this study, the precursor of metal-organic framework (MOF) was synthesized by hydrothermal method. Then, the carbon composite vanadyl oxide (N/C@V2O3) was synthesized by vacuum heat treatment and used as cathode material for ZIBs. The electrode material underwent an in situ phase change process during the first charge, where the corundum structure of N/C@V2O3 was oxidized and transformed into layered basic zinc vanadate (N/C@Zn2(OH)3(VO3)). The layered structure helps to achieve fast and stable storage and transport of zinc ions. Resulting in stable electrochemical performance, high specific capacity up to 285 mAh g−1 (1 A g−1), and ultra-long cycle stability (capacity retention of 98% at 10 A g−1 after 4500 cycles). In situ phase transition takes place inside the battery, which is a simple method to improve the theoretical capacity limit of materials, and has positive significance for realizing large magnification and long cycle ZIBs cathode materials.

Triggering High Capacity and Superior Reversibility of Manganese Oxides Cathode via Magnesium Modulation for Zn//MnO2 Batteries.

Aqueous zinc-ion batteries (ZIBs) have attracted extensive attention in recent years because of its high volumetric energy density, the abundance of zinc resources, and safety. However, ZIBs still suffer from poor reversibility and sluggish kinetics derived from the unstable cathodic structure and the strong electrostatic interactions between bivalent Zn2+ and cathodes. Herein, magnesium doping into layered manganese dioxide (Mg-MnO2 ) via a simple hydrothermal method as cathode materials for ZIBs is proposed. The interconnected nanoflakes of Mg-MnO2 possess a larger specific surface area compared to pristine δ-MnO2 , providing more electroactive sites and boosting the capacity of batteries. The ion diffusion coefficients of Mg-MnO2 can be enhanced due to the improved electrical conductivity by doped cations and oxygen vacancies in MnO2 lattices. The assembled Zn//Mg-MnO2 battery delivers a high specific capacity of 370mAhg-1 at a current density of 0.6Ag-1 . Furthermore, the reaction mechanism confirms that Zn2+ insertion occurred after a few cycles of activation reactions. Most important, the reversible redox reaction between Zn2+ and MnOOH is found after several charge-discharge processes, promoting capacity and stability. It believes that this systematic research enlightens the design of high-performance of ZIBs and facilitates the practical application of Zn//MnO2 batteries.

Oxygen vacancies and heterointerface co-boosted Zn2+ (De)intercalation kinetics in VO2 for ultra-efficient aqueous zinc-ion batteries

In this study, we demonstrated the co-modification of oxygen vacancies and heterojunctions in VO2(B) (VO–VO2/MXene) as a cathode material for zinc-ion batteries (ZIBs). VO2 nanobelts are uniformly distributed on MXene nanosheets, which providing complete electron transport channels during the insertion or de-insertion of Zn2+. The formation of oxygen vacancies provides additional active sites and enhances the conductivity of VO2. Density functional theory calculations reveal that the oxygen vacancies effectively facilitate reversible intercalation/deintercalation process, which results in rapid intra-crystal zinc ion diffusion. The combination of VO–VO2 with MXene introduces an interfacial electric field, ultimately leading to synergistic enhancement in electrochemical activity. The VO–VO2/MXene composite exhibits the highest specific capacity (287 mAh g−1) at 10 A g−1 and excellent cycling lifespan (253 mAh g−1 after 3000 cycles) for ZIBs. This work provides a reliable strategy for the co-modification of metal oxide electrodes with oxygen vacancies and heterostructures.

Hexagonal Carbon Nanoplates Decorated with Layer-Engineered MoS2: High-Performance Cathode Materials for Zinc-Ion Batteries.

Hexagonal carbon nanoplates bearing MoS2 (HCN@MoS2) were synthesized using two-dimensional (2D) microporous organic polymers as templating materials. The layer number of MoS2 in HCN@MoS2 and the 2D morphology of composites were critical factors to achieve high-performance cathode materials for aqueous zinc-ion batteries. The best cathode performance was obtained with HCN@MoS2 bearing 2-3 layered MoS2 (HCN@MoS2-2), showing excellent discharge capacities of 602 mAh/g (@50 mA/g), 498 mAh/g (@0.1 A/g), and 328 mAh/g (@1 A/g). The promising electrochemical performance of HCN@MoS2-2 is attributable to the facilitated insertion of zinc ions into 2-3 layered MoS2 due to the reduced lattice energy and the efficient electrochemical utilization of composite materials.

Amorphous carbon and carbon nanotubes synergistically reinforced with MnO2 as a cathode material for zinc-ion batteries

Amorphous carbon and carbon nanotubes synergistically reinforced with MnO2 as a cathode material for zinc-ion batteries

Supramolecular Engineering of Cathode Materials for Aqueous Zinc-ion Energy Storage Devices: Novel Benzothiadiazole Functionalized Two-Dimensional Olefin-Linked COFs.

Two-dimensional covalent organic frameworks (COFs) have emerged as promising materials for energy storage applications exhibiting enhanced electrochemical performance. While most of the reported organic cathode materials for zinc-ion batteries use carbonyl groups as electrochemically-active sites, their high hydrophilicity in aqueous electrolytes represents a critical drawback. Herein, we report a novel and structurally robust olefin-linked COF-TMT-BT synthesized via the aldol condensation between 2,4,6-trimethyl-1,3,5-triazine (TMT) and 4,4'-(benzothiadiazole-4,7-diyl)dibenzaldehyde (BT), where benzothiadiazole units are explored as novel electrochemically-active groups. Our COF-TMT-BT exhibits an outstanding Zn2+storage capability, delivering a state-of-the-art capacity of 283.5 mAh g-1at 0.1 A g-1. Computational and experimental analyses reveal that the charge-storage mechanism in COF-TMT-BT electrodes is based on the supramolecularly engineered and reversible Zn2+coordination by the benzothiadiazole units.

In Situ Electrochemically Oxidative Activation Inducing Ultrahigh Rate Capability of Vanadium Oxynitride/Carbon Cathode for Zinc-Ion Batteries.

As a promising candidate for large-scale energy storage, aqueous zinc-ion batteries (ZIBs) still lack cathode materials with large capacity and high rate capability. Herein, a spherical carbon-confined nanovanadium oxynitride with a polycrystalline feature (VNxOy/C) was synthesized by the solvothermal reaction and following nitridation treatment. As a cathode material for ZIBs, it is interesting that the electrochemical performance of the VNxOy/C cathode is greatly improved after the first charging process viain situ electrochemically oxidative activation. The oxidized VNxOy/C delivers a greatly enhanced reversible capacity of 556 mAh g-1 at 0.2 A g-1 compared to the first discharge capacity of 130 mAh g-1 and a high capacity of 168 mAh g-1 even at 80 A g-1. The ex situ characterizations verify that the insertion/extraction of Zn2+ does not affect the crystal structure of oxidized VNxOy/C to promise a stable cycle life (retain 420 mAh g-1 after 1000 cycles at 10 A g-1). The experimental analysis further elucidates that charging voltage and H2O in the electrolyte are curial factors to activate VNxOy/C in that the oxygen replaces the partial nitrogen and creates abundant vacancies, inducing a conversion from VNxOy/C to VNx-mOy+2m/C and then resulting in considerably strengthened rate performance and improved Zn2+ storage capability. The study broadens the horizons of fast ion transport and is exceptionally desirable to expedite the application of high-rate ZIBs.

Intercalation-induced amorphous hydrated vanadium oxide for boosted aqueous Zn2+ storage.

An amorphous hydrated vanadium oxide induced by Zn2+ intercalation in Mg-ion inserted V2O5·nH2O (MgVOH) is developed as a high-performance cathode for ZIBs. In particular, zinc pyrovanadate as the product of the second phase transition is found to suppress the dissolution issue of the vanadium species for the cathode to facilitate long lifespan.

Oxygenated copper vanadium selenide composite nanostructures as a cathode material for zinc-ion batteries with high stability up to 10 000 cycles.

The development of aqueous zinc-ion batteries (AZiBs) towards practical implementations is hampered by unsuitable host cathode materials. Herein, we reported a high-capacity, stable, and long-cycle-life (10 000 cycles) oxygenated copper vanadium selenide composite material (Cu0.59V2O5/Cu0.828V2O5@Cu1.8Se1/Cu3Se2, denoted as O-CuVSe) as a cathode for AZiBs. The newly constructed O-CuVSe composite cathode can be operated in the wide potential window of 0.4-2.0 V, exhibiting a high specific capacity of 154 mA h g-1 at 0.2 A g-1 over 100 cycles. Interestingly, the O-CuVSe composite cathode delivered excellent specific capacities of 117 and 101.4 mA h g-1 over 1000 cycles at 1 and 2 A g-1, respectively. Even at a high current density of 5 A g-1, the cathode delivered a high reversible capacity of 74.5 mA h g-1 over an ultra-long cycling life of 10 000 cycles with no obvious capacity fading. Apart from this, the cathode exhibited excellent rate capability at different current densities. The superior electrochemical properties originate from the synergistic effects between the oxygen vacancy engineering and interlayer doping of Cu ions to increase the structural stability during the cycling, enhancing the electron/ion transport kinetics. Moreover, the Zn2+ storage mechanism in the Zn/O-CuVSe aqueous rechargeable battery was explored. This study provides a new opportunity for the fabrication of different kinds of a new class of cathode materials for high-voltage and high-capacity AZiBs and other energy storage devices.

Defect Chemistry in Zn3V4(PO4)6

Zinc-ion batteries have attracted great interest for their low cost, safety, and high energy density. Recently, Zn3V4(PO4)6 has been reported to be a promising cathode material for zinc-ion batteries. The defect chemistry, diffusion of Zn-ions, and solution of dopants are examined by advanced simulation techniques. The simulation results show that the most favorable intrinsic defect is the Zn-V anti-site. A zig-zag pattern of long-range Zn2+ diffusion is observed and the activation energy of 1.88 eV indicates that the ionic conductivity of this material is low. The most promising isovalent dopants on the Zn site are Ca2+ and Fe2+. Although the solution of Ga3+, Sc3+, In3+, Y3+, Gd3+, and La3+ on the V site is exoergic, the most promising is In3+. Different reaction routes for the formation of Zn3V4(PO4)6 are considered and the most thermodynamically favorable reaction consists of binary oxides (ZnO, V2O3, and P2O5) as reactants.

Ni‐MnO2/Graphene as Cathode Material for Super‐Capacity Aqueous Rechargeable Zn‐Ion Battery

The development of cathode materials is an effective way to improve the electrochemical performance of zinc‐ion batteries (ZIBs). Herein, Ni2+‐doped MnO2/graphene nanocomposites (denoted as NMO/rGO) are synthesized by hydrothermal and mechanical ball milling methods as cathode materials for ZIBs. The NMO/rGO electrode shows a super capacity, excellent rate performance, and good cycling stability. The specific discharge capacity can reach 431.5 mAh g−1 at 0.1 A g−1. Moreover, the specific capacity retention rate is 56% after 2200 cycles at 2 A g−1. The excellent electrochemical performance is attributed on the one hand to the stable insertion of Ni2+, which affects the MnO bond and weakens the electrostatic interaction between MnO2 and Zn2+ and on the other hand, the strong interaction (MnOC bond) is formed between NMO and rGO through ball milling, which improves the electrical conductivity and mitigates the volume expansion. Notably, mechanical ball milling can also introduce oxygen vacancies for MnO2, thus increasing the active sites for redox reactions and significantly improving the electrochemical performance of the materials.

De/protonation associated sustainable conversion reaction applicable to high-capacity zinc storage in mildly acidic aqueous system

We introduce an unexpected finding of the de/protonation associated conversion reaction occurred in K2V3O8 as a promising cathode material for zinc-ion batteries. The structure undergoes a conversion reaction between amorphous V5+2O5 and V3+OOH upon cycling when a cut-off voltage up to 1.9 V is applied. A combination of operando X-ray diffraction, in situ Raman spectroscopy, X-ray photoelectron spectroscopy, time-of-flight secondary-ion mass spectroscopy, and operando pH measurement analyses reveal that the reaction of the proton (H+) is indispensable for progression of the conversion reaction. The conversion reaction results in a large reversible capacity of 362 mAh g−1 (∼97 % of theoretical capacity) at 0.1 C (37 mA g−1) on discharge and an activity even at a rate of 7 C (187 mAh g−1), with the two-electron reaction by the V5+/3+ redox pair evidenced by operando X-ray absorption spectroscopy analysis. These findings underscore the importance of conversion reversibility associated with the proton reaction for a high cut-off voltage, contributing additional capacity to reach the theoretical capacity for cathode materials of zinc-ion batteries in mildly acidic aqueous systems.

Organic Zinc-Ion Battery: Planar, π-Conjugated Quinone-Based Polymer Endows Ultrafast Ion Diffusion Kinetics.

A novel poly(phenazine-alt-pyromellitic anhydride) (PPPA) has been successfully designed and synthesized via a condensation polymerization strategy as promising cathode material in organic zinc-ion batteries. Electrochemical quartz crystal microbalance (EQCM), FTIR and XPS characterizations verify a reversible Zn2+ -coordination mechanism in our PPPA cathode. Intriguingly, an ultrahigh Zn2+ diffusion coefficient of 1.2×10-7 cm2 s-1 was found in this large π-conjugated system, which is the highest one among all organic cathode materials for zinc-ion batteries. Theoretical calculations reveal the extended π-conjugated plane in our PPPA sample results in a significant reduction on energy gap, effectively accelerating intramolecular electron transfer during charge/discharge process. Our finding provides insights to achieve high zinc-ion transport kinetics by a design strategy on planar polymer system.

One-step co-precipitation of MnSe2/CNTs as a high-performance cathode material for zinc-ion batteries

One-step room temperature liquid-phase co-precipitation technology is applied in the field of energy storage, which has the advantages of mass production and simple operation. Using this technique, we have directly synthesized MnO2 and amorphous MnSe2. By compounding with carbon nanotubes, the prepared electrodes achieved high discharge capacity (451.1 mAh·g−1 at 0.1 A g−1) and remarkable cycling stability (87.24% after 2000 cycles). The Zn//MnSe2/CNTs battery shows excellent power density (3762 W kg−1) and energy density (301 Wh·Kg−1). This work is expected to achieve mass production of electrode materials, which provides great potential for the application of Selenium in zinc-ion batteries.

Sn-Doped Hydrated V2O5 Cathode Material with Enhanced Rate and Cycling Properties for Zinc-Ion Batteries

Water molecules and cations with mono, binary, and triple valences have been intercalated into V2O5 to significantly improve its electrochemical properties as a cathode material of zinc-ion batteries. Sn as a tetravalent element is supposed to interact aggressively with the V2O5 layer and have a significant impact on the electrochemical performance of V2O5. However, it has been rarely investigated as a pre-intercalated ion in previous works. Hence, it is intriguing and beneficial to develop water molecules and Sn co-doped V2O5 for zinc-ion batteries. Herein, Sn-doped hydrated V2O5 nanosheets were prepared by a one-step hydrothermal synthesis, and they demonstrated that they had a high specific capacity of 374 mAh/g at 100 mA/g. Meanwhile, they also showed an exceptional rate capability with 301 mAh/g even at a large current density of 10 A/g, while it was only 40 mAh/g for the pristine hydrated V2O5, and an excellent cycling life (87.2% after 2500 cycles at 5 A/g), which was far more than the 25% of the pure hydrated V2O5. The dramatic improvement of the rate and cycling performance is mainly attributed to the faster charge transfer kinetics and the enhanced crystalline framework. The remarkable electrochemical performance makes the Sn-doped hydrate V2O5 a potential cathode material for zinc-ion batteries.

Sodium vanadate microflowers as cathode for high-capacity and long-life aqueous zinc-ion battery

Aqueous zinc-ion batteries (ZIBs) have become increasingly popular in energy storage devices on account of their high safety, low cost, high theoretical specific capacity and low redox potential. However, the practical application of ZIBs has been hindered by cathode materials that usually exhibit low capacity or poor cycling performance. In our work, sodium vanadium oxide (NaV8O20) microflowers with nanosheet structure were prepared by hydrothermal method. As cathode materials of ZIBs, NaV8O20 microflowers deliver a high initial specific capacity of 427.6 mAh g−1 at 0.1 A g−1. Surprisingly, the capacity retention rate is about 77% after 7000 cycles at a high current density of 15 A g−1. These excellent electrochemical performances can be attributed to the pre-intercalation of Na+ ions to enhance the electrode stability and the nanosheet structure to increase the number of active sites, indicating that the aqueous ZIBs based on NaV8O20 microflowers has potential application value for large-scale energy storage.

Engineering hydrated vanadium oxide by K+ and Ni2+ incorporation for aqueous zinc ion batteries

It is confirmed that K+ introduction is a feasible approach to lead hydrated vanadium pentoxide to a new phase of KVOH which is considered a cathode material with substantial potential for aqueous zinc ion batteries (ZIBs). Nevertheless, the desire to pursue higher value of specific capacity is still a barrier to its development of applications. Herein, a Ni-doped KVOH (KNiVOH) is developed to achieve higher value of specific capacity. Besides, Ni2+ introduction can intensify the conductivity and encourage the electronic rearrangement, which is advantageous to the electrochemical characteristic and chemical kinetics of the KNiVOH. Furthermore, Ni2+ can make KVOH's K–O bond become more stable by decreasing the energy of formation. As regards the specific capacity value, KNiVOH displays the value of 275 mAh g−1 at 5A g−1, which is better than KVOH (266 mAh g−1). Consequently, these properties recommend KNiVOH as a promising cathode material candidate of ZIBs, indicating it is a practical strategy to combine potassium with other transition metals to synthesize new cathode materials for ZIBs in the future.