With a near-theoretical capacity of 250 mAh/g, excellent rate capability, and cycle life, as well as high energy and power densities of 760 Wh/kg and 1200 W/kg, respectively, these bilayered V2O5 systems can be used in applications at ambient temperature. Sodium-based batteries are particularly attractive alternatives to lithium-based batteries because sodium is a cheap, nontoxic, and abundant element that is uniformly distributed around the world.
Ex situ and in situ synchrotron studies revealed that sodium ion uptake induces organization of the layered vanadia structure together with appearance of long-range order between the layers. Upon deintercalation of sodium, the long-range order is lost while the intralayer structure is still preserved. Inducing ordering of nanomaterials in operando has thus allowed the realization of the highest possible electrode capacity by optimizing the balance of electrostatic forces.