Effect of solvent composition on a one-dimensional (NH4)2V10O25·8H2O electroactive material for electrochemical hydrogen storage application

Abstract

Electrode materials with tailored shapes for one-dimensional (ID) nanorods were manufactured using a solvothermal approach. Different conditions led to the formation of samples with diverse morphologies and compositions. Structural characteristics were studied using XRD, FT-IR, EDX, FE-SEM, TEM and BET analysis (NH₄)₂V₆O₁₆ and (NH₄)₂V₁₀O₂₅·8H₂O structures were obtained under these conditions. The charge–discharge test was conducted to compare the activity of electrode materials with different phase purities. After 15 cycles at a current density of 1 mA, the fabricated (NH₄)₂V₁₀O₂₅·8H₂O material displayed a capacity of 956 mA h g⁻¹, and a maximum capacity of 5268 mA h g⁻¹ was obtained at the 7th cycle. However, the (NH₄)₂V₆O₁₆ electrode material showed 324 mA h g⁻¹ capacity. Vanadium-based materials have poor conductivity. Therefore, designing 1D structures improves the hydrogen storage efficiency of the electrodes. The optimized sample with a nanorod structure and (NH₄)₂V₁₀O₂₅·8H₂O phase purity shows a surface area of 23.571 m² g⁻¹.