High-performance of copper-doped vanadium pentoxide porous thin films cathode for lithium-ion batteries

In this work, porous Cu-doped V 2 O 5 · n H 2 O thin film electrodes have been directly synthesized via low-temperature annealing and simple drop-casting method from V 2 O 5 /H 2 O 2 sol with various concentration copper ion (Cu 2+ ). It is interesting to find that the mass fraction of Cu 2+ has effects on the morphologies, valence state of vanadium, and electrochemical performance of Cu-doped V 2 O 5 · n H 2 O thin film. When the mass fraction of Cu 2+ is 1 wt.%, the obtained Cu-doped V 2 O 5 · n H 2 O thin film electrode shows network porous nanostructure. Moreover, it still shows high discharge specific capacity of 344 mAh g −1 at a current density of 250 mA g −1 . Excellent cycling stability with only 0.14% per cycle degradation during 104 cycles can be obtained even at a high current density of 550 mA g −1 . Improvement of electrochemical performance is attributed to unique network porous nanostructure, accelerating the lithium-ion transfer rate in the de-intercalation or intercalation process.