Hydrogen Peroxide Tuned Morphology and Crystal Structure of Barium Vanadate-Based Nanostructures for Aqueous Zinc-Ion Storage Properties.

Improving the layered-structure stability and suppressing vanadium (V) dissolution during repeated Zn2+ insertion/extraction processes are key to promoting the electrochemical stability of V-based cathodes for aqueous zinc (Zn)-ion batteries (AZIBs). In this study, barium vanadate (Ba2V2O7, BVO) nanostructures (NSs) are synthesized using a facile hydrothermal method. The formation process of the BVO NSs is controlled by adjusting the concentration of hydrogen peroxide (H2O2), and these NSs are employed as potential cathode materials for AZIBs. As the H2O2 content increases, the corresponding electrochemical properties demonstrate a discernible parabolic trend, with an initial increase, followed by a subsequent decrease. Benefiting from the effect of H2O2 concentration, the optimized BVO electrode with 20 mL H2O2 delivers a specific capacity of 180.15 mA h g-1 at 1 A g-1 with good rate capability and a long-term cyclability of 158.34 mA h g-1 at 3 A g-1 over 2000 cycles. Thus, this study provides a method for designing cathode materials with robust structures to boost the electrochemical performance of AZIBs.

Oxygenated copper vanadium selenide composite nanostructures as a cathode material for zinc-ion batteries with high stability up to 10 000 cycles.

The development of aqueous zinc-ion batteries (AZiBs) towards practical implementations is hampered by unsuitable host cathode materials. Herein, we reported a high-capacity, stable, and long-cycle-life (10 000 cycles) oxygenated copper vanadium selenide composite material (Cu0.59V2O5/Cu0.828V2O5@Cu1.8Se1/Cu3Se2, denoted as O-CuVSe) as a cathode for AZiBs. The newly constructed O-CuVSe composite cathode can be operated in the wide potential window of 0.4-2.0 V, exhibiting a high specific capacity of 154 mA h g-1 at 0.2 A g-1 over 100 cycles. Interestingly, the O-CuVSe composite cathode delivered excellent specific capacities of 117 and 101.4 mA h g-1 over 1000 cycles at 1 and 2 A g-1, respectively. Even at a high current density of 5 A g-1, the cathode delivered a high reversible capacity of 74.5 mA h g-1 over an ultra-long cycling life of 10 000 cycles with no obvious capacity fading. Apart from this, the cathode exhibited excellent rate capability at different current densities. The superior electrochemical properties originate from the synergistic effects between the oxygen vacancy engineering and interlayer doping of Cu ions to increase the structural stability during the cycling, enhancing the electron/ion transport kinetics. Moreover, the Zn2+ storage mechanism in the Zn/O-CuVSe aqueous rechargeable battery was explored. This study provides a new opportunity for the fabrication of different kinds of a new class of cathode materials for high-voltage and high-capacity AZiBs and other energy storage devices.

Carbon-Shielded Selenium-Rich Trimetallic Selenides as Advanced Electrode Material for Durable Li-Ion Batteries and Supercapacitors.

In order to achieve a sustainable future, researchers must continue to research improved electrode materials. Considering the high electronic conductivity, versatile redox activity, and enhanced energy storage performance, nanostructures have been employed as a novel electrode material for high-performance lithium-ion batteries (LIBs) and supercapacitors. Herein, carbon-coated selenium-rich trimetallic selenide (Cu2 NiSnSe4 @C) nanoparticles (NPs) as an efficient electrode material in energy storage devices are prepared. The prepared core-shell Cu2 NiSnSe4 @C NPs electrode is employed as an anode material for LIBs, which demonstrated a high reversible specific capacity of 988.46 mA h g-1 over 100 cycles at 0.1 A g-1 with good rate capability. Additionally, the core-shell Cu2 NiSnSe4 @C NPs electrode exhibited an outstanding capacity of 202.5 mA h g-1 at 5 A g-1 even after 10 000 cycles. Exploiting the synergistic characteristics, the core-shell Cu2 NiSnSe4 @C NPs material is also investigated as a battery-type electrode for hybrid supercapacitors. The assembled hybrid supercapacitor with Cu2 NiSnSe4 @C NPs and activated carbon showed excellent rate capability including high power (5597.77 W kg-1 ) and energy (64.26 Wh kg-1 ) densities. Considering the simple synthesis and enhanced energy storage properties, carbon-coated selenium-rich trimetallic selenide can be used as a durable electrode material for practical energy storage devices.