Facile Synthesis of Ordered Mesoporous Orthorhombic Niobium Oxide (T-Nb$_2$O$_5$) for High-Rate Li-Ion Storage with Long Cycling Stability

Herein, we describe the synthesis and evaluation of hierarchical mesoporous orthorhombic niobium oxide (T-Nb$_2$O$_5$) 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 m$^2$ g$^{−1}$) and pore volume (0.135 cm3 g$^{−1}$). As for the application in Li-ion devices, the T-Nb$_2$O$_5$ 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-Nb$_2$O$_5$ 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. ... mehrThe origin of the improved performance of T-Nb$_2$O$_5$ results from the high surface area and mesoporous structure of the nanoparticles.