Vanadium oxide cathode materials in aqueous aluminum-ion batteries (AAIBs) have an exceptional potential for development because of their high valence and fast electron transfer capability. However, the strong electron–electron Coulomb repulsion in vanadium and its associated electrostatic interactions severely hinder the feasibility of vanadium oxides in AAIBs. The glucose-assisted hydrothermal reduction of monoclinic VO 2 combined with Cu ion doping effectively promotes the self-assembly of VO 2 into nanoflower architectures, enabling precise control over morphology and crystalline structure. When integrated with a 5 m Al(OTF) 3 electrolyte and an Ionic liquid （IL ）-treated Al sheet anode, this full battery demonstrates outstanding electrochemical performance, achieving an initial discharge capacity of 642 mAh·g −1 at 0.4 A·g −1 . Moreover, introducing Cu 3d orbitals effectively enhances the hybridization and electronic coupling effects between the V 3d and O 2p orbitals. Ex situ characterization and diffusion kinetic provide insights into the embedding/de-embedding mechanism of Al 3+ . This work significantly improves the application potential of VO 2 in AAIBs through structural optimization and mechanism studies and provides systematic scientific guidance for the development of vanadium oxide cathode materials.
Photon upconversion holds tremendous promise in many fields, including photovoltaics, biological imaging, and multi-dimensional display. However, insufficient upconversion emission intensity still limits its utilization for many potential applications. Herein, a type of VO2 (B) nanoflowers with unique size and high crystalline quality, exhibiting a bright upconversion emission, is reported. More importantly, a new method, i.e., higher power-sensitization, is established to improve upconversion emission signals. After higher power-sensitization, a drastic increase in upconversion emission intensity to 553-fold and 158-fold was observed for green and total emissions, respectively, at a pump power of 90 mW. At the same time, the upconversion of light at low excitation powers (2, 90 mW) was observable by the naked eye. We identified that the welded structure, favouring the energy transfer from sensitizers to activators, was key for achieving this enhancement. This study not only suggests a new pathway for building high-efficiency upconversion systems, but also provides insights for improving the practical applications of upconversion materials.
Developing high energy density room-temperature sodium sulfur (RT Na-S) batteries relies on the design of delicate structure that can be efficiently injected sulfur and enhance the cycle life of electrode active material. Herein, a three dimensional (3D) hierarchical cathode substrate with VO 2 nanoflowers as catalyst in situ grown on reduced graphene oxide (rGO) for sulfur cathodes are designed and prepared. In this novel structure, the electronic conductivity of sulfur cathode can be greatly improved due to the high electrical conductivity of rGO substrate. More importantly, the catalytic effect of VO 2 accelerates the conversion long-chain NaPSs to Na 2 S 2 /Na 2 S, and enhances the cycle capability, which can be validated by experimental data. As a result, the as-obtained rGO/VO 2 /S composites achieves an initial reversible capacity of 876.4 mA h g −1 at 0.2C. Moreover, the capacity of 156.1 mA h g −1 is demonstrated after long-cycling term of 1000 cycles at 2C and high cycle stability of only 0.07% capacity decay per cycle is exhibited.
危险品化学品经营许可证（带存储）