Granular Vanadium Nitride (VN) Cathode for High-Capacity and Stable Zinc-Ion Batteries

Unleashing Vanadium-Based Compounds for High-Energy Aqueous Zinc-Ion Batteries

Rechargeable aqueous zinc-ion batteries (ZIBs) are poised as a promising solution for large-scale energy storage and portable electronic applications. Their appeal lies in their affordability, abundant materials, high safety standards, acceptable energy density, and eco-friendliness. Vanadium-based compounds stand out as potential cathode materials due to their versatile phases and variable crystal structures, empowering design flexibility to affect the theoretical capacity. However, challenges, such as V dissolution and substantial capacity degradation, have hindered their widespread use. Recent breakthroughs in crafting innovative V-based materials for aqueous ZIBs, by preintercalating guest species, have significantly bolstered structural stability and facilitated faster charge migration, leading to enhanced capacity and stable cycling. This review delves into the latest advancements in vanadium-based cathodes with preintercalated guest species, examining their altered crystal structures and the mechanisms involved in Zn2+ ion storage. It also investigates how different guest materials within these cathodes impact the electrochemical capacity. Additionally, this assessment identifies key obstacles impeding progress and proposes potential solutions while also anticipating the future trajectory of aqueous ZIBs. These insights are invaluable to researchers and manufacturers alike, offering a roadmap for commercialization.

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 are hoped to flourish in the coming years and attract more and more researchers' attention.

Progressive activation of porous vanadium nitride microspheres with intercalation-conversion reactions toward high performance over a wide temperature range for zinc-ion batteries

Rechargeable aqueous zinc-ion batteries have great promise for becoming next-generation storage systems, although the irreversible intercalation of Zn²⁺ and sluggish reaction kinetics impede their wide application. Therefore, it is urgent to develop highly reversible zinc-ion batteries. In this work, we modulate the morphology of vanadium nitride (VN) with different molar amounts of cetyltrimethylammonium bromide (CTAB). The optimal electrode has porous architecture and excellent electrical conductivity, which can alleviate volume expansion/contraction and allow for fast ion transmission during the Zn²⁺ storage process. Furthermore, the CTAB-modified VN cathode undergoes a phase transition that provides a better framework for vanadium oxide (VO_x). With the same mass of VN and VO_x, VN provides more active material after phase conversion due to the molar mass of the N atom being less than that of the O atom, thus increasing the capacity. As expected, the cathode displays an excellent electrochemical performance of 272 mAh g^-1 at 5 A g^-1, high cycling stability up to 7000 cycles, and excellent performance over a wide temperature range. This discovery creates new possibilities for the development of high-performance multivalent ion aqueous cathodes with rapid reaction mechanisms.

High-performance Zn-ion batteries constructed by in situ conversion 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.

Layer-by-layer stacked vanadium nitride nanocrystals/N-doped carbon hybrid nanosheets toward high-performance aqueous zinc-ion batteries

Aqueous zinc ion batteries (AZIBs) hold great potential in large scale, low-cost energy storage. Unfortunately, their development is limited by the poor performing cathode materials due to their unstable structures and low capacities. Hence, we develop novel layer-by-layer stacked vanadium nitride nanocrystals/N-doped carbon hybrid nanosheets (VN/NC) as cathode materials by in situ thermal conversion of pyrolyzing pentyl viologen intercalated V₂O₅. The combination of a leaf-like morphology, the nano structure of vanadium nitride crystals and the conductive porous nitrogen-doped carbon nanosheets endow the VN/NC cathode with excellent electrochemical performance in AZIBs. Thus, it delivers a high discharge specific capacity of 566 mA h g^-1 at a current density of 0.2 A g^-1 and a superior rate capability. Most importantly, it exhibits a remarkable cyclic stability with capacity retention of 131 mA h g^-1 (85% of the initial capacity) after 1000 cycles at a current density of 10 A g^-1. The design of the unique VN/NC hybrid nano sheets offers a pathway towards developing high performance electrode materials for energy storage.

Ammonium vanadate cathode materials with enhanced Zn storage by the optimization of electrolytes

Rechargeable metal ion batteries have been alternatives to traditional fossil fuels in the past decade. Thereinto, aqueous zinc-ion batteries (AZIBs) have attracted one’s widespread attention due to their high theoretical...