Nanostructured Nb₂O₅ Polymorphs by Electrospinning for Rechargeable Lithium Batteries

Polymorphs of 1D nanostructures of niobium pentoxide (Nb 2 O 5 ) are synthesized by electrospinning. Pseudohexagonal (H−Nb 2 O 5 ), orthorhombic (O−Nb 2 O 5 ), and monoclinic (M−Nb 2 O 5 ) structures of Nb 2 O 5 are developed in this study by appropriate heat treatment. Morphological, structural, and electrochemical properties of these nanofibrous polymorphs are studied in detail. The H− and O− phases maintain the usual fibrous morphology, whereas the M− phase adopted a distorted nugget structure. These phases are evaluated for their application as cathode for lithium batteries. The M−Nb 2 O 5 exhibits the highest capacity and better capacity retention compared to the other phases. The M−Nb 2 O 5 delivers a specific capacity of 242(±3) and 218(±3) mAhg −1, cycled at a current of 50 mAg −1 in the voltage range, 1.0−2.6 V versus Li/Li + at the end of second and 25th cycle, respectively. The electrospun M−Nb 2 O 5 nuggets-based battery performs better than its particle/nanofiber counterpart and could be a cathode material of choice for 2 V due to the commercial viability of the electrospinning process and characteristics of the batteries developed herewith.