Structural modulation of Nb2O5 for enhanced Lithium-ion battery Performance: Insights from density functional theory and electrochemical characterization

Abstract

Lithium-ion batteries (LIBs), extensively utilized today, encounter challenges with anode materials, such as capacity degradation and shortened cycle life during prolonged cyclic charging and discharging. These issues significantly hinder further advancements and applications of LIBs. Among various innovative anode materials, niobium pentoxide (Nb2O5) has garnered considerable interest due to its high specific capacity and exceptional cycling stability. However, different crystal types of Nb2O5 have different structures and properties, so they need to be studied in depth to find better anode materials for LIBs. In this paper, pseudo-hexagonal (TT-Nb2O5), orthorhombic (T-Nb2O5), and monoclinic (H-Nb2O5) crystalline forms of Nb2O5 have been prepared by simple ball milling and calcination methods. We have calculated the structural model of the material based on the density flooding theory (DFT), and the results have demonstrated that the T-Nb2O5 has a large structural advantage, which is characterized by a very low diffusion energy barrier, a low internal resistance, and a higher conductivity. The electrochemical properties of the material were also analyzed, and T-Nb2O5 has excellent cycling stability and rate performance. After 200 cycles (at 0.1A/g), the specific capacity of T-Nb2O5 was maintained at 440.8mAh/g. 3000 cycles at high current (at 5A/g) maintained a specific capacity of 95mAh/g. T-Nb2O5 has great potential, which has already been proved. With the continuous pursuit and development of energy storage technology, we believe that the research of different crystalline types of Nb2O5 will provide us with more efficient and reliable energy storage solutions.