Reduced graphene oxide and carbon nanotube anchored NASICON-type NaTi2(PO4)3 nanocomposite anodes for high-rate performance sodium-ion batteries

Abstract

NASICON-structured NaTi2(PO4)3 (NTP) anode consist of an open 3D framework is received as a zero-stress anode for Na-ion batteries. Herein, we have reported a novel NTP/GO/CNT nanocomposite anodes, in which NTP particles are engineered with reduce graphene oxide (rGO) and carbon nano tube (CNT) and wrapped using a low-cost facile sol-gel method. NTP-rGO10-CNT10 has been chosen as the optimum electrode after studying the effects of rGO/CNT ratio on the electrochemical performance of NTP. The combine effect of structural integrity, high electronic conductivity and high ionic diffusivity in NTP-rGO10-CNT10 leads to excellent electrochemical performance with regards to specific capacity (124 mA h g−1 at 100 mA g−1), remarkable high-rate cycleability (62.5% capacity retention after 400 cycles at 10 C), and excellent rate capability (87 mA h g−1 at 25C). Using cyclic voltammetry investigation, we have estimated the capacitive and faradaic contributions to the total capacities of the composite electrode at various rate. Besides, carbon incorporated NVOPF obtained by carbo-thermal reduction delivers a specific discharge capacity of 106 mA h g−1 as cathode against sodium. Finally, a Na-ion full-cell with the structure of NTP-rGO10-CNT10│1 M NaClO4 in PC│NVOPF@C has been fabricated. This newly designed full-cell can deliver good electrochemical performance in terms of cycleability and power.