Thermolysis-Driven Growth of Vanadium Oxide Nanostructures Revealed by In Situ Transmission Electron Microscopy: Implications for Battery Applications.

Understanding the growth modes of 2D transition-metal oxides through direct observation is of vital importance to tailor these materials to desired structures. Here, we demonstrate thermolysis-driven growth of 2D V 2 O 5 nanostructures via in situ transmission electron microscopy (TEM). Various growth stages in the formation of 2D V 2 O 5 nanostructures through thermal decomposition of a single solid-state NH 4 VO 3 precursor are unveiled during the in situ TEM heating. Growth of orthorhombic V 2 O 5 2D nanosheets and 1D nanobelts is observed in real time. The associated temperature ranges in thermolysis-driven growth of V 2 O 5 nanostructures are optimized through in situ and ex situ heating. Also, the phase transformation of V 2 O 5 to VO 2 was revealed in real time by in situ TEM heating. The in situ thermolysis results were reproduced using ex situ heating, which offers opportunities for upscaling the growth of vanadium oxide-based materials. Our findings offer effective, general, and simple pathways to produce versatile 2D V 2 O 5 nanostructures for a range of battery applications.