A simple and versatile method for the preparation of V6O13 microflowers is developed via a simple hydrothermal route with the aid of an alkali metal nitrate salt, which has important effects on the formation of V6O13. It is found that V6O13 microflowers display good cycling stability as cathode materials for lithium-ion battery. In addition, they show high capacities for sodium-ion battery. We have V6O13 microflowers discharge capacities up to 225.7 mA h g(-1) for sodium-ion battery. The reason may be the fewer phase transitions occurring upon lithium and sodium insertion for phase-unpure V6O13 microflowers. (C) 2014 Elsevier Inc. All rights reserved.