Yolk-shell V2O3/nitrogen-doped carbon spheres as an ultra-long life anode for half/full sodium-ion batteries

Abstract

With abundant resources and multiple electron transfer, V2O3 is a potential anode material for sodium ion batteries (SIBs). However, dramatic volume changes and slow reaction kinetics during the charge/discharge process still limit its application. Herein, porous yolk-shell V2O3/nitrogen-doped carbon (V2O3/NC) spheres are produced by a simple solvothermal method combined with subsequent carbonization. In this hierarchical structure, ultra-fine nanoparticles as primary building unit facilitate ion/electron transport; unique yolk-shell structure relieves the volume strain improving the structure integrity; nitrogen-doped carbon enhances electrochemical conductivity; moreover, rational mesoporous structure accelerates electrolyte penetration and high specific surface area supplies abundant reaction sites. Based on the above merits, yolk-shell V2O3/NC spheres exhibit satisfactory sodium ion storage performance (129.5 mAh g−1 at 5.0 A g−1 after 12,000 ultra-long cycles). What's more, an assembled V2O3/NC//Na3V2(PO4)3 full cell displays outstanding cycle performance (46 mAh g−1 after 300 cycles at 0.2 A g−1), demonstrating its potential value for practical applications.