One-pot synthesis of hierarchical Ni3S2 nanorods-embedded flower-shaped NiMn-LDH microspheres for electrochemical hydrogen storage

Over the years, alloys have been the predominant choice of electrode material for electrochemical hydrogen storage. However, they encounter challenges emerging from their complex synthesis process and intricate structure, leading to low discharge capacity. Hierarchical Ni3S2 nanorods-embedded flower-shaped NiMn-layered double hydroxide (LDH) microspheres (∼10 μm) are, thus, synthesized via a facile one-pot binder-free hydrothermal process and examined for their electrochemical hydrogen storage behavior. The Ni3S2/Ni2Mn1-LDH composite showcased superior reversibility and a maximum storage capacity of ∼860 mAh/g at 1000 mA/g current density under ambient temperature and pressure conditions. It exhibited a Coulombic efficiency of ∼86% and a capacity retention rate of ∼98% even after 100 charge-discharge cycles in 3 M KOH electrolyte. The enhanced electrochemical performance is attributed to the layered morphology and synergistic behavior demonstrated by the Ni3S2 nanorods on the LDH layers. To this end, the material emerges as a promising and efficient candidate to be utilized in energy storage systems.