Electrospun Single-Phase Na_1.2V₃O₈ Materials with Tunable Morphologies as Cathodes for Rechargeable Lithium-Ion Batteries

Single-phase Na_1.2V₃O₈ materials with single and hierarchical nanobelt morphologies were prepared by using a versatile electrospinning technique by altering the sintering profiles. On the basis of characterization by field-emission scanning electron microscopy and high-resolution transmission electron microscopy, the formation mechanisms of products with tunable morphologies are discussed. The products obtained are employed as cathode materials for lithium-ion batteries. Their electrochemical activities are demonstrated through galvanostatic cycling and cyclic voltammetry. The non-agglomerated, single nanobelts with exposed (100) facets, which serve as channels for facile lithium diffusion, are capable of exhibiting higher maximum capacities of approximately 218 mAhg^-1 compared to hierarchical nanobelts with a maximum capacity of approximately 197 mAhg^-1 versus Li/Li⁺ at a current density of 200 mAg^-1. Their associated reversible capacities are approximately 207 and 173 mAhg^-1, respectively, after 100 cycles. Single nanobelts with individual belt-like structures and preferred facet orientation also exhibit better rate capabilities.