Polymorphs of Nb 2 O 5 Compound and Their Electrical Energy Storage Applications.

Niobium pentoxide (Nb 2 O 5 ), as an important dielectric and semiconductor material, has numerous crystal polymorphs, higher chemical stability than water and oxygen, and a higher melt point than most metal oxides. Nb 2 O 5 materials have been extensively studied in electrochemistry, lithium batteries, catalysts, ionic liquid gating, and microelectronics. Nb 2 O 5 polymorphs provide a model system for studying structure-property relationships. For example, the T-Nb 2 O 5 polymorph has two-dimensional layers with very low steric hindrance, allowing for rapid Li-ion migration. With the ever-increasing energy crisis, the excellent electrical properties of Nb 2 O 5 polymorphs have made them a research hotspot for potential applications in lithium-ion batteries (LIBs) and supercapacitors (SCs). The basic properties, crystal structures, synthesis methods, and applications of Nb 2 O 5 polymorphs are reviewed in this article. Future research directions related to this material are also briefly discussed.