▎ 摘　　要

Due to a growing demand for sustainable electrical energy storage alternatives to Li-ion batteries (LIBs), Na-ion batteries (SIBs) are of great interest because of the abundance of Na+. By modifying layered H2V3O8 by preintercalation and composite formation, improved electrochemical properties were obtained in LIBs. In analogy, a scalable soft chemistry synthesis is developed, to chemically presodiate H2V3O8 for the first time, in addition to a composite formation reaction with reduced graphene oxide (rGO). Crystal structure and morphology of all compounds are determined and their electrochemical properties as cathode are evaluated with respect to both Na+ and Li+ intercalation. The combination of preintercalation and composite formation leads to excellent initial capacities of 96 mAh . g(-1) for SIBs and 371 mAh . g(-1) for LIBs (58 % and 48 % higher than unmodified H2V3O8) at a practical current density of 100 mA . g(-1), demonstrating that H2V3O8 is a promising cathode material for SIBs and LIBs.