Facile Synthesis of Ordered Mesoporous Orthorhombic Niobium Oxide (T-Nb₂O₅) for High-Rate Li-Ion Storage with Long Cycling Stability

Herein, we describe the synthesis and evaluation of hierarchical mesoporous orthorhombic niobium oxide (T-Nb₂O₅) as an anode material for rechargeable lithium-ion batteries (LIB). The as-synthesized material addresses key challenges such as beneficial porous structure, poor rate capability, and cycling performance of the anode for Li-ion devices. The physicochemical characterization results reveal hierarchical porous nanostructure morphology with agglomerated particles and a 20 to 25 nm dimension range. Moreover, the sample has a high specific surface area (~65 m² g⁻¹) and pore volume (0.135 cm³ g⁻¹). As for the application in Li-ion devices, the T-Nb₂O₅ delivered an initial discharging capacity as high as 225 mAh g⁻¹ at 0.1 A g⁻¹ and higher rate capability as well as remarkable cycling features (~70% capacity retention after 300 cycles at 250 mA g⁻¹) with 98% average Coulombic efficiency (CE). Furthermore, the scan rate-dependent charge storage mechanism of the T-Nb₂O₅ electrode material was described, and the findings demonstrate that the electrode shows an evident and highly effective pseudocapacitive Li intercalation behaviour, which is crucial for understanding the electrode process kinetics. The origin of the improved performance of T-Nb₂O₅ results from the high surface area and mesoporous structure of the nanoparticles.