Open-Structured V2O5•nH2O Nanoflakes as Highly Reversible Cathode Material for Monovalent and Multivalent Intercalation Batteries

The high-capacity cathode material V2O5 center dot nH(2)O has attracted considerable attention for metal ion batteries due to the multielectron redox reaction during electrochemical processes. It has an expanded layer structure, which can host large ions or multivalent ions. However, structural instability and poor electronic and ionic conductivities greatly handicap its application. Here, in cell tests, self-assembly V2O5 center dot nH(2)O nanoflakes shows excellent electrochemical performance with either monovalent or multivalent cation intercalation. They are directly grown on a 3D conductive stainless steel mesh substrate via a simple and green hydrothermal method. Well-layered nanoflakes are obtained after heat treatment at 300 degrees C (V2O5 center dot 0.3H(2)O). Nanoflakes with ultrathin flower petals deliver a stable capacity of 250 mA h g(-1) in a Li-ion cell, 110 mA h g(-1) in a Na-ion cell, and 80 mA h g(-1) in an Al-ion cell in their respective potential ranges (2.0-4.0 V for Li and Na-ion batteries and 0.1-2.5 V for Al-ion battery) after 100 cycles.