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In this research, the steric effect of an exfoliation agent between n‐ethylamine and triethylamine for the fabrication of Ca2Nb3O10− nanosheet was investigated. The experimental results revealed that the different structures of the exfoliation agent have affected to fabrication of Ca2Nb3O10− nanosheet. The use of n‐ethylamine as an exfoliation agent gave a maximum exfoliation efficiency of 10 wt.% while the maximum exfoliation efficiency of triethylamine was 90 wt.%. The result showed that the difference in exfoliation efficiency was caused by the steric effect of exfoliation agents. The image of transmission electron microscopy exhibited Ca2Nb3O10− nanosheets which were formed by exfoliation of HCa2Nb3O10. Furthermore, the reaction time for liquid exfoliation was studied in this work. The reaction time at 4 h gave a maximum of exfoliation efficiency. The Ca2Nb3O10− suspension was tested capability to remove hazardous ions. After the experiment, we found the white precipitate which was the formation of CsCa2Nb3O10. The result showed that the Ca2Nb3O10− nanosheet was efficient for the removal of Cs+ ions in the wastewater. [ABSTRACT FROM AUTHOR]

Aqueous zinc ion batteries (AZIBs) are garnering significant attention as a promising energy storage system owing to their high safety, low cost, and environmental friendliness. Among various cathode materials, one-dimensional (1D) tunnel vanadium-based cathode materials have been extensively studied for their excellent electrochemical performance. In this mini review, we present a summary of recent research progress on 1D tunnel VO2(B) cathode materials for AZIBs. Specifically, we delve into their crystal structure, morphology, and charge–discharge mechanism, and the impact of various synthesis and modification methods on their morphology and electrochemical performance. Additionally, we provide insights into key strategies employed to enhance the electrochemical performance of VO2(B). Furthermore, we underscore both the opportunities and challenges in this domain while also discussing the future prospects for the development of 1D tunnel VO2(B) cathode materials in AZIBs. [ABSTRACT FROM AUTHOR]

Energy 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+. [ABSTRACT FROM AUTHOR]

Aqueous zinc ion batteries (AZIBs) offer a promising approach for electrical energy storage, combining cost-effectiveness and enhanced thermal safety. However, the cathode material, vanadium oxide, while known for its excellent theoretical specific capacity, faces a challenge in terms of its poor electronic conductance. In this study, we present a novel strategy to address this limitation by constructing the V5O12·6H2O/V6O13/CNT (VOH/CNT) nanocomposite, resulting in significantly improved electrochemical performance. This nanocomposite was synthesized through a facile solvothermal method, yielding a unique floral spherical structure featuring a central cluster and multiple smaller groupings. The integration of CNTs into the composite significantly enhanced its electronic conductance, effectively mitigating the electronic conductance issue associated with vanadium oxide. Moreover, the composite retains crystalline water within its structure, playing a crucial role in providing a favorable ion-conductive pathway. Consequently, the VOH/CNT nanocomposite exhibits an impressive reversible capacity of 201 mA h g−1 at 50 mA g−1, surpassing that of VOH (116 mA h g−1). Remarkably, even at a high current density, the VOH/CNT nanocomposite demonstrates an exceptional capacity retention, maintaining a capacity of 150 mA h g−1 over 500 cycles at 1 A g−1. Its outstanding electrochemical performance can be attributed to its distinctive structural arrangement, the conductive network facilitated by CNTs, and the introduced crystalline water component. [ABSTRACT FROM AUTHOR]

Electrode materials are the key to the electrochemical performance of supercapacitors. This study reports the electrochemical properties of V2O5 supercapacitors. V2O5 nanosheets with different morphologies were prepared by controlling the solvent under a facile hydrothermal method. The phase and the morphology of the samples were characterized by x-ray diffraction and scanning electron microscopy. The electrochemical properties of V2O5 nanosheets with different morphologies were studied by cyclic voltammetry, galvanostatic charge–discharge, and electrochemical impedance spectroscopy. The charge transfers resistance decreases from 3.2 Ω of V2O5 particles to 2.0 Ω of V2O5 nanosheets. V2O5 nanosheets exhibit higher specific capacity (375 F g−1) than V2O5 particles (318 F g−1) in K2SO4 solution. The cycling capacity retention keeps 96.8% for 1000 cycles at 0.5 A g−1 in K2SO4 solution, indicating better cycling stability. [ABSTRACT FROM AUTHOR]

Advanced cathode materials for high power and great cycle stability have attracted much attention. Layer-structured NH4V3O8 (NVO) has been intensively studied because by their large distance between the layers and high discharge capacity. Nevertheless, the cycling stability of NVO is seriously restrained by the low electrical conductivity and poor lithium-ion diffusion ability. In this research, reduced graphene oxide nanosheets decorated carbon-coated NH4V3O8 (G-NVO@C) were synthesized through a facile one-step solvothermal method. As the cathode material for lithium-ion batteries, the G-NVO@C electrode exhibits outstanding cycling stability. The first discharge capacity is 220.6 mAh g−1 at a current density of 15 mA g−1. After 200 cycles, the discharge capacity is still maintained as high as 172.6 mAh g−1, and a retention of 78.2% was achieved. It is noteworthy that the specific discharge capacity decreased rapidly only in the first five cycles and then stabilized. These characteristics indicate that the G-NVO@C electrode has a broad application as cathode material for lithium-ion batteries. [ABSTRACT FROM AUTHOR]