Polydopamine-derived N-doped carbon-wrapped Na3V2(PO4)3 cathode H with superior rate capability and cycling stability for sodium-ion I batteries

摘要

Na superionic conductor (NASICON)-type Na3V2(PO4)3 (NVP) has been regarded as a promising cathode material for sodium-ion batteries (SIBs). However, NVP suffers from poor cyclability and rate capability because of its intrinsically low electronic conductivity. Herein, we successfully syn thesized N-doped carb on-wrapped Na3V2(PO4)3 (NC@NVP) through the carb on izati on of polydopami ne, which is rich in nitrogen species. The strong adhesion properties of the polydopamine lead to effective and homogeneous wrapping of NVP particles, and it I is further turned into a con ductive N-doped carb on n etwork itself, providi ng facile diffusi on of electr ons and Na+ i ons duri ng battery operation. NC@NVP displays remarkable electrochemical performanee, even under harsh operating conditions, such as a high rate capability (discharge capacity of 70.88, 49.21 mA·h·g^-1 at 50 and 100 C), long-term cycling stability (capacity retention of 94.77% over 1,000 cycles at 20 C), and high-temperature cycling (capacity retention of 92.0% after 500 cycles at 60 ℃).