H₂V₃O₈ Nanowires as High-Capacity Cathode Materials for Magnesium-Based Battery

Magnesium-based batteries have received much attention as promising candidates to next-generation batteries because of high volumetric capacity, low price, and dendrite-free property of Mg metal. Herein, we reported H₂V₃O₈ nanowire cathode with excellent electrochemical property in magnesium-based batteries. First, it shows a satisfactory magnesium storage ability with 304.2 mA h g^–1 capacity at 50 mA g^–1. Second, it possesses a high-voltage platform of ∼2.0 V vs Mg/Mg²⁺. Furthermore, when evaluated as a cathode material for magnesium-based hybrid Mg²⁺/Li⁺ battery, it exhibits a high specific capacity of 305.4 mA h g^–1 at 25 mA g^–1 and can be performed in a wide working temperature range (−20 to 55 °C). Notably, the insertion-type ion storage mechanism of H₂V₃O₈ nanowires in hybrid Mg²⁺/Li⁺ batteries are investigated by ex situ X-ray diffraction and Fourier transform infrared. This research demonstrates that the H₂V₃O₈ nanowire cathode is a potential candidate for high-performance magnesium-based batteries

Lattice Breathing Inhibited Layered Vanadium Oxide Ultrathin Nanobelts for Enhanced Sodium Storage

Operating as the “rocking-chair” battery, sodium ion battery (SIB) with acceptable high capacity is a very promising energy storage technology. Layered vanadium oxide xerogel exhibits high sodium storage capacity. But it undergoes large lattice breathing during sodiation/desodiation, resulting in fast capacity fading. Herein, we develop a facile hydrothermal method to synthesize iron preintercalated vanadium oxide ultrathin nanobelts (Fe-VO_<i>x</i>) with constricted interlayer spacing. Using the Fe-VO_<i>x</i> as cathode for SIB, the lattice breathing during sodiation/desodiation is largely inhibited and the interlayer spacing is stabilized for reversible and rapid Na⁺ insertion/extraction, displaying enhanced cycling and rate performance. This work presents a new strategy to reduce the lattice breathing of layered materials for enhanced sodium storage through interlayer spacing engineering

High-Performance Na–O₂ Batteries Enabled by Oriented NaO₂ Nanowires as Discharge Products

Na–O₂ batteries are emerging rechargeable batteries due to their high theoretical energy density and abundant resources, but they suffer from sluggish kinetics due to the formation of large-size discharge products with cubic or irregular particle shapes. Here, we report the unique growth of discharge products of NaO₂ nanowires inside Na–O₂ batteries that significantly boosts the performance of Na–O₂ batteries. For this purpose, a high-spin Co₃O₄ electrocatalyst was synthesized via the high-temperature oxidation of pure cobalt nanoparticles in an external magnetic field. The discharge products of NaO₂ nanowires are 10–20 nm in diameter and ∼10 μm in length, characteristics that provide facile pathways for electron and ion transfer. With these nanowires, Na–O₂ batteries have surpassed 400 cycles with a fixed capacity of 1000 mA h g^–1, an ultra-low over-potential of ∼60 mV during charging, and near-zero over-potential during discharging. This strategy not only provides a unique way to control the morphology of discharge products to achieve high-performance Na–O₂ batteries but also opens up the opportunity to explore growing nanowires in novel conditions