Design of vanadium oxide structures with controllable electrical properties for energy applications

The electrical properties of inorganic materials has been a long-standing pursued research topic, and successfully controlling the electrical property of an inorganic material has attracted significant attention for a wide range of energy-related applications, covering energy storage, energy conversion and energy utilization. During the few past decades, vanadium oxides have been studied to gain a clear picture of how microstructural characteristics generating the e-e correlations influence the electronic structure of a material, through which the charge concentration, electrical conductivity as well as the metal-insulator transition (MIT), etc., can be precisely controlled, giving promising signs for constructing energy-related devices. In this review, we present an extensive review of the engineering of the microstructures of vanadium oxides with control of their electrical properties, and with attempts to rationally construct energy-related devices, such as aqueous lithium ion batteries, supercapacitors for energy storage, and thermoelectric generators for energy conversion. Furthermore, the MIT performance of vanadium oxides has also seen tremendous advantages for the applications of "smart windows'' and magnetocaloric refrigerators for energy utilization. Collectively, progresses to date suggest that in vanadium oxide systems, the electrical properties, including electrical conductivity, carrier concentrations, and the MIT performance, were all strongly dependent on the microstructural characteristics at the atomic scale, which have presented extensive promising energy applications covering energy storage, energy conversion and energy utilization.