Tube-on-rod structure of MWCNTs-ammonium cobalt vanadium oxide/ammonium vanadium oxide; evaluation of electrochemical hydrogen storage capacity

Abstract

Carbon nanostructures have lately been widely used in energy storage systems. This study examines the impact of ammonium cobalt vanadium oxide/ammonium vanadium oxide as electrode materials in hydrogen storage which modifying with carbon nanostructures. The poor conductivity of vanadate-based materials may be improved by adding zero to two-dimensional carbon nanomaterials, such as graphene quantum dots (GQDs), graphene oxide (GO), and multiwall carbon nanotubes (MWCNTs). Electrode materials based on (NH4)2V12O27·xH2O/(NH4)2Co2V10O28·16H2O/NH4V3O8 were synthesized by hydrothermal method in the presence of PEG with engineered morphology of one dimensional (ID) nanorods. The carbonous nanocomposites based on GQDs, MWCNTs and GO exhibit a capacity 203, 438 and 28 mAhg−1 after 15 cycles at a current density of 1 mA. The hydrogen storage performance is influenced by various amount of MWCNTs. Increasing the percentage of MWCNTs led to decreasing the capacity. Therefore, optimum electrode materials fabricated in the presence of 5 % MWCNTs which has 1055 mAhg−1 capacity. Therefore, 1D/1D structure of Tube-on-Rod can improve the performance of hydrogen storage in the ammonium cobalt vanadium oxide/ammonium vanadium oxide electrodes.