Hydrated vanadium pentoxide/reduced graphene oxide composite cathode material for high-rate lithium ion batteries

As well-known, hydrated vanadium pentoxide (V₂O₅·nH₂O) has a larger layer spacing than orthogonal V₂O₅, which could offer more active sites to accommodate lithium ions, ensuring a high specific capacity. However, the exploration of V₂O₅·nH₂O cathode is limited by its inherently low conductivity and slow electrochemical kinetics, leading to a significant decrease in capability. Herein, we prepared V₂O₅·nH₂O/reduced graphene oxide (rGO) composite with low rGO content (8 wt%) via a simple yet effective dual electrostatic assembly strategy. When used as the cathode material for lithium-ion batteries (LIBs), V₂O₅·nH₂O/rGO manifests a high reversible capacity of 268 mAh g^-1 at 100 mA g^-1 and especially an excellent rate capability (196 mAh g^-1 at 1000 mA g^-1 and 129 mA h g^-1 at 2000 mA g^-1), surpassing those of the V₂O₅/carbon composites reported in the literatures. Notably, the remarkable performance should be referable to the synergetic effects between one-dimensional V₂O₅·nH₂O nanobelts and two-dimensional rGO nanosheets, which provide a short transport pathway and enhanced electrical conductivity. This strategy opens a new opportunity for designing high-performance cathode material with excellent rate performance for advanced LIBs.