Carbon-Decorated Na3V2(PO4)3 as Ultralong Lifespan Cathodes for High-Energy-Density Symmetric Sodium-Ion Batteries

In this work, several carbon-decorated Na3V2(PO4)3 materials (NVP@C-750/800/850) are successfully fabricated using a sol–gel approach and subsequent heat treatment. When NVP@C-800 is used as a cathode, it shows an ultralong cycle life (2000 cycles) at a high rate of 10C, which is superior to the other two electrodes and those of reported NVP@C cathodes in the literature. The excellent results of NVP@C-800 are attributed to its nanostructure and the well-defined conductive carbon layer. The symmetric sodium (Na)-ion battery (SIB) with NVP@C-800 as both a cathode and an anode shows a high capacity at 40 mA g–1 with a voltage plateau of about 1.79 V and energy density of 113 W h kg–1, revealing that NVP@C is of great application prospect.