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H2V3O8 has been regarded as a compelling cathode material for aqueous zinc-ion batteries (AZIBs) owing to its elevated theoretical capacity, abundance of vanadium valence states, and advantageous layered configuration. Nonetheless, the intrinsically low conductivity and sluggish ionic reaction kinetics of H2V3O8 result in undesirable, constraining its broader implementation in AZIBs. In this study, a facile hydrothermal approach was utilized to prepare H2V3O8 nanowires with an abundance of oxygen vacancies. The combination of nanowire nanostructure and oxygen vacancies of the H2V3O8 offer improved ion diffusion kinetics and enhanced electronic conductivity, leading to a superior improved electrochemical performance. Particularly, the H2V3O8 nanowire cathodes with the optimal oxygen vacancy concentration (HVO-20) exhibit a specific capacity of 461.7 mAh g−1 at 0.3 A g−1 and exceptional cycle life of 198.8 mAh g−1 after 1000 cycles at 1.0 A g−1. The investigation unveils the impact of oxygen vacancy vanadium-based oxides on the performance of AZIBs, presenting a viable strategy for advanced cathode materials in AZIBs. [ABSTRACT FROM AUTHOR]

In this study, VO2/V2O5 heterostructures were successfully prepared by a hydrothermal and in-situ sintering procedure and were studied as aqueous zinc ion batteries (AZIBs). The novel heterostructure plays a critical role in controlling electrochemical performance. X‒ray diffraction analysis showed that the heterostructures were composed mainly of the orthorhombic VO2 and monoclinic V2O5 phases. Compared with pristine VO2 and V2O5, the VO2/V2O5 heterostructure showed excellent electrochemical properties when applied as a cathode for AZIBs. The cathode materials showed a high specific capacity of 453.6 mA h g−1 at 0.2 A g−1, considerable rate performance and capacity retention of 85.6% after 800 cycles at a scan rate of 1 A g−1. The X‒ray photoelectron spectra indicated the chemical components and elemental valence and the impedance analysis indicated the charge transfer kinetics. The method proposed herein provides a strategy for designing AZIBs with high capacity and fast ion diffusion rate. [ABSTRACT FROM AUTHOR]

La0.7Sr0.3CoO3 with perovskite structure is a promising electrode material for supercapacitors, but its charge storage capacity is limited due to its inherent poor conductivity. Herein, our work used a simple sol–gel method to combine carbon quantum dots coupled with La0.7Sr0.3CoO3 to enhance the electrical conductivity of electrode materials and studied the synergistic effect of oxygen vacancy and carbon quantum dots to improve the electrochemical performance of electrode materials. The morphology, structure, and elemental valence of La0.7Sr0.3CoO3/CQDs were characterized by XRD, SEM, TEM, and XPS. Compared with La0.7Sr0.3CoO, La0.7Sr0.3CoO3-CQDs shows low resistivity, excellent electrical conductivity, and high specific capacitance; it showed high specific capacitance (878.1 F/g at 0.5 A/g), excellent rate performance (69.2% capacitance retention at 20A/g), and long cycle life. These results indicate that the synergistic effect of oxygen vacancies and carbon quantum dots in perovskite metal oxides improves the electrode performance of supercapacitors and provides a new idea for improving the electrode performance of electrode materials. [ABSTRACT FROM AUTHOR]

SnO2-based composites have drawn much attention as anode materials for lithium ion batteries due to their high specific capacity. However, they also suffer from rapid capacity fading, which is attributed the poor electronic conductivity and severe volume change. Therefore, it is important to enhance the electronic conductivity and inhibit the volume change at the same time. Based on this theme, herein, hollow SnO2@C composites with perfect structure and high electronic conductivity are synthesized and used as anode materials for lithium ion batteries. The as-prepared hollow SnO2@C composites exhibit high initial specific capacity of 1628 mAh g−1 at 0.1C. The superior electrochemical performance is due to the hollow sphere structure of hollow SnO2@C composites, which could provide novel synthetic method for improving electronic conductivity and buffer the volume change. [ABSTRACT FROM AUTHOR]

The present study investigates the structural and chemical factors contributing to the performance of graphene oxide anode materials produced by Hummers (GOH) and Tour (GOT) for lithium-ion batteries (LIBs). The GO synthesized by these methods were studied using FTIR and Raman spectroscopy, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and scanning electron microscopy (SEM). Thorough electrochemical analysis including cycling stability, rate capability, cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS) were also conducted. We show that the improved performance of GOT (almost twice) compared with that of GOH is due to the key role of the protective agent (H3PO4) in reducing/inhibiting the hole formation during the synthesis of the GOT surface which in turn results in superior cycling performance over the GOH. The results and proposed mechanism presented in this work elucidates the role of structural factors and defects in preparing graphene-based anodes with enhanced electrochemical efficiency. [ABSTRACT FROM AUTHOR]