High-performance surface optimized Mg-doped V2O5 (Mg@V2O5) cathode material via a surfactant-assisted hydrothermal technology for lithium-ion and lithium-sulfur batteries

Vanadium pentoxide (V 2 O 5 ) has attracted extensive attention due to its high specific capacity, low cost, high energy density, and rich sources. In this paper, Mg-doped V 2 O 5 (Mg@V 2 O 5 ) with excellent structure as energy storage material is synthesized via a surfactant-assisted hydrothermal technology. Physical characterization indicates that the Mg@V 2 O 5 synthesized with the assistance of sodium dodecyl sulfate (SDS-Mg@V 2 O 5 ) has higher specific surface area (20.84 m 2 /g), uniformly smaller crystal size (2–40 nm), and rich pore structure. As the cathode active materials for lithium-ion batteries, the initial discharge specific capacities can achieve to 411.13 mAh g −1 at 0.2 C and the capacity retention rate is 46.4% after 110 cycles. In addition, after the carbon coating, SDS-Mg@V 2 O 5 is used as sulfur-wrapping matrix material for lithium-sulfur batteries and the initial discharge specific capacities can achieve 1325.76, 1147.34, and 938.79 mAh g −1 at 0.1, 0.2, and 0.5C, respectively. After 140 cycles, the capacity retention rate still remains at 86.7%.