Reticular V2O5·0.6H2O Xerogel as Cathode for Rechargeable Potassium Ion Batteries

• DOI: 10.1021/acsami.7b15407
• Publication Date: 2017-12-19T19:29:10Z
• Authors: Bingbing Tian; Wei Tang; Chenliang Su; Ying Li
• Keywords: Orthorhombic crystal system; Pentoxide

Potassium ion batteries (KIBs), because of their low price, may exhibit advantages over lithium as potential candidates for large-scale energy storage systems. However, owing to the large ionic radii K-ions, it is challenging find a suitable intercalation host KIBs and thus rechargeable KIB electrode materials are still largely unexplored. In this work, reticular V2O5·0.6H2O xerogel was synthesized via hydrothermal process cathode material KIBs. Compared with orthorhombic crystalline V2O5, hydrated vanadium pentoxide (V2O5·0.6H2O) exhibits ability accommodating larger alkali metal ions K+ enlarged layer space by hosting structural H2O molecules in interlayer. By into V2O5 layers, its potassium electrochemical activity significantly improved. It an initial discharge capacity ∼224.4 mA h g-1 ∼103.5 even after 500 discharge/charge cycles at current density 50 g-1, which much higher than that without water. Meanwhile, X-ray diffraction photoelectron spectroscopy combined dispersive techniques carried out investigate potassiation/depotassiation electrodes, confirmed mechanisms material. The results demonstrate interlayer-spacing-enlarged promising candidate