Double carbon-embedded Na3V2(PO4)3 as a superior anode for sodium ion batteries

Double carbon-embedded Na3V2(PO4)(3) (DC-NVP) nanocomposites were prepared via in situ growth of NVP@C nanoparticles on carbon nanotubes (CNTs). Beneficial of a high electronic conductivity network and structure stability, the DC-NVP nanocomposite as an anode of sodium ion batteries (SIBs) reveals outstanding electrochemical properties, delivering ultra-long cycle life with a first charge capacity of 78 mA h g(-1) at 50 C and a capacity loss of 0.006%/cycle over 8000 cycles. The NVP//NVP full cells, fabricated by the DC-NVP nanocomposites as bipolar electrode, exhibit a discharge capacity of 72.1 mA h g(-1) at 20 C after 5000 cycles and a corresponding capacity retention of 81%. The remarkable performance of DC-NVP nanocomposites is ascribed to that of the unique double carbon-embedded nanostructure, which possesses good electronic conductivity, larger electrode-electrolyte contact area, fast electron and ion transportation, and structural stability.