NaTi₂(PO₄)₃/Carbon and NaTi₂(PO₄)₃/Graphite Composites as Anode Materials for Aqueous Rechargeable Na-ion Batteries

Abstract

NaTi2(PO4)3/carbon and NaTi2(PO4)3/graphite composites as anode materials for aqueous rechargeable Na–ion batteries were synthesized by modified Pechini method and pyrolysis treatment in the inert atmosphere. The structures and carbon contents of the samples were characterized by X-ray diffraction, Scanning Electron Microscopy and carbon–sulfur analyzer respectively. Electrochemical properties were evaluated by galvanostatic discharge/charge test and cyclic voltammetry using a three-electrode system. The first discharge specific capacity of NaTi2(PO4)3/carbon composites was 128.6 mAh g−1 and maintained 117.4 mAh g−1 after 50 cycles at a discharge rate of 2 C. The reversible capacity of the composites remained 66.2 mAh g−1 even at 20 C. NaTi2(PO4)3/carbon composites exhibited better electrochemical performance than NaTi2(PO4)3 and NaTi2(PO4)3/graphite samples.