Vanadium Oxide Layers Research Articles

Interlayer engineering of V2O5·nH2O by conductive Ni-BTA enabling high-performance aqueous ammonium ion batteries

Aqueous ammonium ion batteries (AAIBs) are of interest due to the low molar mass, small hydration radius, abundant raw materials and high safety of the carrier ammonium-ion. Nevertheless, there are numerous constraints associated with electrode materials that are suitable for ammonium-ion storage. In this study, we design and synthesize a composite comprising of one-dimensional conductive metal-organic skeleton material (1D c-MOF) embedded between layers of hydrated vanadium pentoxide (VOH) with improved ammonium-ion storage. The central ion of the 1D c-MOF is selected to be the nickel ion, while the ligand is 1,2,4,5-benzenetetramine (BTA). The incorporation of Ni-BTA between the vanadium oxide layers results in the formation of a composite (Ni-BTA/VOH) exhibiting enhanced structural stability, augmented layer spacing and elevated conductivity. Furthermore, the dual energy storage mechanisms of VOH and CN rearrangement act in concert to yield a “1+1 > 2” effect, thereby markedly enhancing the ammonium-ion storage. The specific capacity of Ni-BTA/VOH can reach 183 mAh g−1 at 0.2 A g−1, and the retention rate can reach 52.5 % after 500 cycles at 2 A g−1. This work not only proves the potential of Ni-BTA/VOH for widespread application in the field of aqueous batteries, but also provides a new method for structural engineering of VOH with boosted ammonium-ion storage properties.

Unraveling Energy Storage Performance and Mechanism of Metal-Organic Framework-Derived Copper Vanadium Oxides with Tunable Composition for Aqueous Zinc-Ion Batteries.

Achieving high-performance aqueous zinc (Zn)-ion batteries (AZIBs) requires stable and efficient cathode materials capable of reversible Zn-ion intercalation. Although layered vanadium oxides possess high Zn-ion storage capacity, their sluggish kinetics and poor conductivity present significant hurdles for further enhancing the performance of AZIBs. In response to this challenge, a dissolution-regrowth and conversion approach is formulated using metal-organic frameworks (MOFs) as a sacrificial template, which enables the in situ creation of copper vanadium oxides (CuVOx) with porous 1D channels and distinctive nanoarchitectures. Owing to their distinctive structure, the optimized CuVOx cathode experiences a reaction involving the synergistic insertion/extraction of Zn2+, resulting in rapid Zn2+ diffusion kinetics and enhanced electrochemical activity postactivation. Specifically, the activated electrode delivers a reversible capacity of 519mAhg-1 at 0.5Ag-1 for AZIBs. It is noteworthy that the electrode exhibits a remarkable reversible rate capacity of 220mAhg-1 at 5Ag-1 with excellent durable cycleability, retaining 88% of its capacity even after 3000 cycles. Various ex situ testing methods endorse the reversible insertion/extraction of Zn2+ in the CuVOx cathode. This study provides a novel insight into high-performance MOF-derived unique structure designs for AZIB electrodes.

Progress and Challenges of Vanadium Oxide Cathodes for Rechargeable Magnesium Batteries.

Among the challenges related to rechargeable magnesium batteries (RMBs) still not resolved are positive electrode materials with sufficient charge storage and rate capability as well as stability and raw material resources. Out of the materials proposed and studied so far, vanadium oxides stand out for these requirements, but significant further improvements are expected and required. They will be based on new materials and an improved understanding of their mode of operation. This report provides a critical review focused on this material, which is embedded in a brief overview on the general subject. It starts with the main strategic ways to design layered vanadium oxides cathodes for RMBs. Taking these examples in more detail, the typical issues and challenges often missed in broader overviews and reviews are discussed. In particular, issues related to the electrochemistry of intercalation processes in layered vanadium oxides; advantageous strategies for the development of vanadium oxide composite cathodes; their mechanism in aqueous, "wet", and dry non-aqueous aprotic systems; and the possibility of co-intercalation processes involving protons and magnesium ions are considered. The perspectives for future development of vanadium oxide-based cathode materials are finally discussed and summarized.

Nanostructured Layered Vanadium Oxide Modified by Hydrated Manganese Ions for Boosting Zn2+ Storage

Nanostructured Layered Vanadium Oxide Modified by Hydrated Manganese Ions for Boosting Zn²⁺ Storage

On the origin of enhanced electrochemical kinetics in guest-ions pre-intercalated layered vanadium oxides: Interlayer spacing vs lattice distortion

Cathode materials of highly stable structure and high capacity are essentially required for aqueous rechargeable zinc ion batteries (ARZIBs), where layered vanadium oxide hydration (VOH) is one of the most promising cathode materials for reversible zinc ion intercalation/deintercalation. Previous studies have shown that both the interlayer spacing and the Zn-ion storage performance can be altered by the pre-intercalation of certain guest ions between the layers of VOH. In addition to previous discussions on the increase in effective Zn2+ storage as a result of the widening in interlayer spacing after guest ion pre-intercalation, there is a variation in the exposed active O sites, which are shown to be equally important. In the metal ion pre-intercalated layered vanadium oxides, there is a delicate balance between the interlayer spacing and lattice distortion, depending on the type and amount of pre-intercalated metal ions. In particular, those pre-intercalated guest ions with high electronegativity can steadily shift towards the VO layers and break the V-O bonds leading to exposed active O sites. The high electronegativity endows the combination of guest ions with newly exposed O sites. These active O sites give rise to an inhomogeneous distribution of the charge density, leading to an improvement in electrochemical performance. The present study demonstrates the complicated interplays of more than one parameter in the guest ion pre-intercalated layered vanadium oxides, going much beyond the simple widening in inter-layer spacing.

Joint cationic and anionic redox chemistry in a vanadium oxide cathode for zinc batteries achieving high energy density

AbstractRechargeable aqueous zinc batteries are promising for large‐scale energy storage due to their low cost and high safety; however, their energy density has reached the ceiling based on conventional cathodes with a single cationic redox reaction mechanism. Herein, a highly reversible cathode of typical layered vanadium oxide is reported, which operates on both the cationic redox couple of V5+/V3+ accompanied by the Zn2+ storage and the anionic O–/O2– redox couple by anion hosting in an aqueous deep eutectic solvent electrolyte. The reversible oxygen redox delivers an additional capacity of ∼100 mAh g–1 at an operating voltage of ∼1.80 V, which increases the energy density of the cathode by ∼36%, endowing the cathode system a record high energy density of ∼506 Wh kg–1. The findings highlight new opportunities for the design of high‐energy zinc batteries with both Zn2+ and anions as charge carriers.

Highly reproducible and CMOS-compatible VO2-based oscillators for brain-inspired computing.

With remarkable electrical and optical switching properties induced at low power and near room temperature (68°C), vanadium dioxide (VO2) has sparked rising interest in unconventional computing among the phase-change materials research community. The scalability and the potential to compute beyond the von Neumann model make VO2 especially appealing for implementation in oscillating neural networks for artificial intelligence applications, to solve constraint satisfaction problems, and for pattern recognition. Its integration into large networks of oscillators on a Silicon platform still poses challenges associated with the stabilization in the correct oxidation state and the ability to fabricate a structure with predictable electrical behavior showing very low variability. In this work, the role played by the different annealing parameters applied by three methods (slow thermal annealing, flash annealing, and rapid thermal annealing), following the vanadium oxide atomic layer deposition, on the formation of VO2 grains is studied and an optimal substrate stack configuration that minimizes variability between devices is proposed. Material and electrical characterizations are performed on the different films and a step-by-step recipe to build reproducible VO2-based oscillators is presented, which is argued to be made possible thanks to the introduction of a hafnium oxide (HfO2) layer between the silicon substrate and the vanadium oxide layer. Up to seven nearly identical VO2-based devices are contacted simultaneously to create a network of oscillators, paving the way for large-scale implementation of VO2 oscillating neural networks.

Forming-Free, Low-Voltage, and High-Speed Resistive Switching in Ag/Oxygen-Deficient Vanadium Oxide(VOx)/Pt Device through Two-Step Resistance Change by Ag Filament Formation.

Forming-free, low-voltage, and high-speed resistive switching is demonstrated in an Ag/oxygen-deficient vanadium oxide (VOx)/Pt device via the facilitated formation and rupture of Ag filaments. Direct current (DC) voltage sweep measurements exhibit forming-free switching from a high-resistance state (HRS) to a low-resistance state (LRS), called SET, at an average VSET of +0.23 V. The reverse RESET transition occurs at an average VRESET of -0.07 V with a low RESET current of <1 mA. Reversible switching operations are stable with an HRS/LRS resistance ratio >103 during repeated measurements for thousands of cycles. In pulse measurements, switching occurs within 100 ns at an amplitude of +1.5 V. Notably, a two-step resistance change is observed in the SET operation, where the resistance first partially decreases due to Ag+ ion accumulation in VOx and then further decreases to the LRS after hundreds of nanoseconds upon complete filament formation. The VOx layer deposited to be mostly amorphous with oxygen deficiency from V2O5 has abundant vacancies and expedites Ag+ ion migration, thus realizing forming-free, high-speed, and low-voltage switching. These characteristics of the facilitated Ag filament formation using the substoichiometric VOx layer are highly beneficial for use as stand-alone nonvolatile memory and in-memory computing elements.

Freestanding Ammonium Vanadate Composite Cathodes with Lattice Self-Regulation and Ion Exchange for Long-Lasting Ca-Ion Batteries.

Calcium-ion batteries (CIBs) have emerged as a promising alternative for electrochemical energy storage. The lack of high-performance cathode materials severely limits the development of CIBs. Vanadium oxides are particularly attractive as cathode materials for CIBs, and preinsertion chemistry is often used to improve their calcium storage performance. However, the room temperature cycling lifespan of vanadium oxides in organic electrolytes still falls short of 1000 cycles. Here, based on preinsertion chemistry, the cycling life of vanadium oxides is further improved by integrated electrode and electrolyte engineering. Utilizing a tailored Ca electrolyte, the constructed freestanding (NH4)2V6O16·1.35H2O@graphene oxide@carbon nanotube (NHVO-H@GO@CNT) composite cathode achieves a 305 mAh g-1 high capacity and 10000 cycles record-long life. Additionally, for the first time, a Ca-ion hybrid capacitor full cell is assembled and delivers a capacity of 62.8 mAh g-1. The calcium storage mechanism of NHVO-H@GO@CNT based on a two-phase reaction and the exchange of NH4 + and Ca2+ during cycling are revealed. The lattice self-regulation of V─O layers is observed and the layered vanadium oxides with Ca2+ pillars formed by ion exchange exhibit higher capacity. This work provides novel strategies to enhance the calcium storage performance of vanadium oxides via integrated structural design of electrodes and electrolyte modification.

Synchronous organic-inorganic co-intercalated ammonium vanadate cathode for advanced aqueous zinc-ion batteries

Vanadium-based cathode materials are attractive for aqueous zinc-ion batteries (AZIBs) owing to the high capacity from their open frameworks and multiple valences. However, the cycle stability and rate capability are still restricted by the low electrical conductivity and trapped diffusion kinetics. Here, we propose an organic–inorganic co-intercalation strategy to regulate the structure of ammonium vanadate (NH4V4O10, NVO). The introduction of Al3+ and polyaniline (PANI) induces the optimized layered structure and generation of urchin-like hierarchical construction (AP-NVO), based on heterogeneous nucleation and dissolution–recrystallization growth mechanism. Owing to these favorable features, the AP-NVO electrode delivers a desirable discharge capacity of 386 mA h g−1 at 1.0 A g−1, high-rate capability of 263 mA h g−1 at 5.0 A g−1 and excellent cycling stability with 80.4% capacity retention over 2000 cycles at 5.0 A g−1. Such satisfactory electrochemical performance is believed to result from the enhanced reaction kinetics provided by the stable layered structure and a high intercalation pseudo-capacitance reaction. These results could provide enlightening insights into the design of layered vanadium oxide cathode materials.

Ultra-stable aqueous nickel-ion storage achieved by iron-ion pre-introduction assisted hydrated vanadium oxide cathode

Aqueous Nickel-ion batteries (ANIBs) are attracting growing attention for next-generation energy storage devices, but their development is hindered by deficient satisfactory cathode materials and undefined reaction mechanisms. Herein, a novel layered vanadium oxide with Fe3+-ions pillars (Fe0.29V2O5·0.57H2O, FVO) is developed and innovatively used for effective Ni2+ ion storage. The large interlayer spacing and abundant oxide vacancies of FVO can provide broad ion migration channels and rich ion storage sites. The pre-intercalated Fe3+-ions can firmly support the integrity of the layered structure by Fe-O bonds to achieve excellent cycle stability. RGO is further introduced to construct the FVO@G composite can improve the conductivity and stability of the FVO electrode. As a result, the FVO@G electrode exhibits exceptional Ni2+ storage performance of 169.8 mAh g−1 at 0.5C and ultrahigh capacity retention of 91.9% after 320 cycles at 10C. The Ni2+ storage mechanism in FVO@G is clarified by in-situ XRD and ex-situ Raman, ex-situ XPS techniques, the results show that FVO@G undergoes a phase transition accompanied by an expansion of the interlayer spacing upon the first charging, and the electrodes display a high degree of structural reversibility and a negligible volume expansion during the subsequent cycles. Furthermore, density functional theory (DFT) calculations show that FVO provides efficient diffusion paths along the b-axis with ultrafast transport kinetics. This work is a significant step in ANIBs research and provides valuable insights for the design of high-performance ANIBs cathode material.

Layered vanadium oxides: Promising cathode materials for calcium-ion batteries

Layered vanadium oxides: Promising cathode materials for calcium-ion batteries

Building stabilized Cu0.17Mn0.03V2O5−□·2.16H2O cathode enables an outstanding room‐/low‐temperature aqueous Zn‐ion batteries

AbstractVanadium 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.

Cell Size Effects and Distinct Current Conduction Behaviors for Hafnium‐Oxide‐Based Selectors with Vanadium as Top Electrode

Selector devices have been incorporated in the resistance random access memory to realize one‐selector‐one‐resistor device for the achievement of high‐density storage applications. Among many possible materials for selector devices, the metal–insulator transition mechanism of the vanadium oxide (VOx) is interesting due to its formation under the influence of temperature. Previous studies have also indicated that VOx is formed after high‐temperature annealing. Herein, the V/HfO2/TiN with different deice cell sizes is investigated. After the forming process, devices with small cell sizes can exhibit threshold switching (TS) characteristics, while devices with large cell sizes can show resistive switching property. Electrical measurements of DC and AC operations are also conducted to verify stable TS characteristics for selector applications. The current fitting method and the computer‐aid simulation are also carried out to compare different current conduction behaviors of devices with large and small cell sizes, which indicates that heat plays an important role in the formations of VOx layer of the V/HfO2/TiN device.

Tix+ in-situ intercalation and interlayer modification via titanium foil/vanadium ion solution interface of VO2.375 as sulfur-wrapped matrix enabling long-life lithium sulfur battery

Lithium sulfur battery (LSB) has great potential as a promising next-generation energy storage system owing to ultra-high theoretical specific capacity and energy density. However, the polysulfide shuttle effect and slow redox kinetics are recognized the most stumbling blocks on the way of commercializing LSB. On this account, for the first time, we use Tix+ in-situ intercalation strategy via titanium foil/vanadium ion (V5+) solution interface to modify the layer of vanadium oxide for long cycle LSB. The inserted Tix+ strengthens interlayer interaction and enhances lithium-ion mobility rate. Meanwhile, based on density functional theory (DFT) calculation, the mixed valence of V5+/V4+ in the vanadium oxide structure reduces the stress and strain of lithium-ion intercalation through the interlayer support of titanium ions (Tix+). Also, Tix+ refines the structural stability of the sulfur wrapped composite matrix so as to facilitate the LiPSs transformation, and improve the electrochemical performances. Consequently, the Ti-VO2.375/S cathode delivers a lower capacity decay of 0.037 % per cycle over 1500 cycles with a stable coulombic efficiency around 100 %.

Ce ions and polyaniline co-intercalation into MOF-derived porous V2O5 nanosheets with a synergistic energy storage mechanism for high-capacity and super-stable aqueous zinc-ion batteries

Layered vanadium oxides with highly open crystal structures and high theoretical capacity are regarded as the most promising cathode materials for high-performance aqueous zinc-ion batteries (ZIBs).

Pair Distribution Function Analysis of Local Structural Rearrangement in Spinel Vanadium Oxide Cathodes

Being a divalent cation with the lowest mass, Mg2+ has garnered quite attention in recent times due to the high volumetric capacity of it’s batteries. Theoretical studies reveal that the combination of a Mg anode and a spinel oxide cathode would be able to surpass the current limits found in widely used Li-ion batteries Therefore, to design materials with high diffusion and reversible insertion capacity, a conclusive demonstration of the intercalation mechanism of Mg2+ into metal oxides, is required.Among the numerous options for cathodes, vanadium oxides show evidence of the largest capability toward reversible intercalation of Mg ions. In particular, spinel-type MgV2O4 shows a capacity of 200 mAh/g, corresponding to the cycling of ~0.7 mol Mg2+ per mol of oxide, and layered α-V2O5 reaches 300 mAhg-1, intercalating 1 mol Mg2+ per mol of oxide. The extent and reversibility of these reactions were confirmed by elemental, redox and structural characterization in recent work [1,2]. This high capacity is only observed at 110°C and it is accompanied by a large hysteresis in potential during the electrochemical cycling. The push to overcome these bottlenecks demands a more comprehensive definition of the underlying mechanisms of reaction than is currently available.Previous X-ray Diffraction (XRD) measurements conducted on the oxide indicated a loss of reflection intensity due to a loss in their crystallinity which makes structural characterization using typical diffraction techniques difficult. Through this work, we mainly make use of pair distribution function techniques to study the changes in the local structures of these oxides in both their pristine and charged state, and the effect of annealing for longer hours with the goal of further pushing the efficiency of multivalent battery materials.Reference: Hu, L., Jokisaari, J.R., Kwon, B.J., Yin, L., Kim, S., Park, H., Lapidus, S.H., Klie, R.F., Key, B., Zapol, P. and Ingram, B.J., 2020. High capacity for Mg2+ deintercalation in spinel vanadium oxide nanocrystals. ACS Energy Letters, 5(8), pp.2721-2727. Yoo, H.D., Jokisaari, J.R., Yu, Y.S., Kwon, B.J., Hu, L., Kim, S., Han, S.D., Lopez, M., Lapidus, S.H., Nolis, G.M. and Ingram, B.J., 2019. Intercalation of magnesium into a layered vanadium oxide with high capacity. ACS Energy Letters, 4(7), pp.1528-1534.

Cobalt ion doping and morphology tailoring enable superior zinc-ion storage in sodium vanadate nanoflowers

Layered sodium vanadium materials have aroused increasing interest owing to their open layered structures and high theoretical capacity. Nevertheless, the strong electrostatic interactions between vanadium oxide layers and intercalated Zn2+ and the weak electronic conductivity severely limit their further development. Here, we design a series of cobalt ion-doped sodium vanadium electrode materials with nanoflower-like morphologies. Due to the open interlayer space and improved electron transfer enabled by cobalt ion preintercalation and sufficient contact area between the electrode and electrolyte provided by the three-dimensional (3D) flower-like morphology, the cobalt ion-doped sodium vanadate (CNVO-2) cathode exhibits excellent electrochemical performance, including an exceptional specific capacity (411 mA h g−1 at 0.5 A g−1) and ultrahigh structural stability (90.4 % capacity retention after 3000 cycles at 10 A g−1), outperforming many advanced ZIBs cathode materials. In addition, through various ex situ characterization techniques, an ionic exchange and multiple ion cointercalation mechanism is first revealed in sodium vanadate cathode material.

Employing the optimized pre-intercalation strategy to design functional Mo pre-intercalated hydrated vanadium oxide for aqueous zinc-ion batteries

The traditional metal ions (K+, Na+, Ca2+, etc.) pre-intercalated strategy is widely used to optimize the structure of vanadium oxides as the cathode materials for aqueous zinc-ion batteries (AZIBs). However, these intercalated ions with a single valence state between the layers of vanadium oxides occupy the original active sites and merely act as ‘pillars’ without redox reactions for energy storage. Herein, we employ the optimized pre-intercalation strategy to fabricate a series of Mo pre-intercalated hydrated vanadium oxide materials (x-MoVOH) as the cathode of AZIBs. The intercalated functional Mo ions can not only effectively enlarge the interlayer spacing to expose more active sites for insertion and de-insertion of hydrated Zn2+, but also provide additional electrochemical performance through the redox reactions of Mo4+/Mo5+/Mo6+. The finest material (Mo3V15O35·nH2O, 5-MoVOH) exhibits the electrochemical performance of the specific capacity of 430 mAh·g−1 at 100 mA·g−1 and the capacity retention proportion of 95 % after 1000 cycles at 2 A·g−1. Additionally, the galvanostatic intermittent titration technique (GITT) further confirms that the enlarged layer spacing facilitates the rapid diffusion of hydrated Zn2+. This work provides a novel and feasible way to further enhance the performance of vanadium oxides in AZIBs.

Coupling of V2O5 structural design and electrolyte modulation toward stable zinc-ion battery

Layered vanadium oxides possess abundant crystal structures and multiple redox states, which account for excellent specific capacity for zinc ion batteries (ZIBs). However, vanadium-based cathodes typically suffer from structural instability and component dissolution, leading to inferior cyclic stability and rate performance. Herein, porous V2O5 slender leaf-like nanostructure anchored on carbon cloth (CC) is synthesized via electrodeposition and subsequent calcination. Taking advantage of the distinctive hierarchical structure and the introduction of propylene carbonate (PC) electrolyte additives, the free-standing VO-C2PC electrode provides a maximum reversible capacity of 555 mA h g−1 at 0.3 A g−1, and high capacity retention of 180 mA h g−1 after 5000 cycles at 10 A g−1. Even at a high mass loading, the VO-C2PC exhibits excellent Zn storage capability and stability. Furthermore, the Zn2+ storage mechanism reveals the gradual transformation of V2O5 into stable zinc pyrovanadate (ZVO) phase, which improves the stable Zn2+ storage capability. This study provides valuable insights into the construction of advanced electrodes and the design of novel electrolytes for high-performance ZIBs.