Three-dimensional Na3V2(PO4)3@carbon/N-doped graphene aerogel: A versatile cathode and anode host material with high-rate and ultralong-life for sodium storage

Abstract

Abstract Na3V2(PO4)3 (NVP) with a unique 3D open NASICON framework is regarded as an attractive electrode material in sodium-ion batteries (SIBs) due to its wide range of Na+ accommodations. Nevertheless, the practical implementation of NVP is hampered by the unsatisfying capabilities and cycling stability at high rates of charging/discharging, which attribute to low electron/ion conductivities. Herein, a novel NVP@carbon/N-doped graphene aerogel (NVP@C/N-GA) is designed via a facile precursor infiltration followed by the post-heating treatment process. In this delicate design, the 3D porous and interconnected framework endows with bicontinuous ion/electron transport pathways for the rapid electrochemical reaction; while the carbon layer combined with N doped graphene aerogel (N-GA) provides long-range conductive networks throughout the whole electrode and ensure the cycling stability. Consequently, the NVP@C/N-GA electrode is shown to achieve unprecedented rate capabilities and outstanding ultralong cycling stability as cathode (74.1 mA h g−1 at 100 C; 84% capacity retention at 20 C after 12,000 cycles) and anode (109.3 mA h g−1 at 20 C; 87% capacity retention at 20 C after 5000 cycles), both of them outperforms the majority of previously reported literature. Moreover, the symmetric full cell assembled by NVP@C/N-GA also demonstrates admirable electrochemical properties. Thus, this work may provide new avenues for constructing electrodes with high rate capability and ultralong-life.