Design and synthesis of three-dimensional NaTi 2 (PO 4 ) 3 @CNT microspheres as advanced anode materials for rechargeable sodium-ion batteries

Abstract NASICON-type NaTi 2 (PO 4 ) 3 with a zero-stress framework has been receiving particular attention as an advanced anode material for high-performance sodium-ion batteries. In this work, the three-dimensional (3D) NaTi 2 (PO 4 ) 3 @CNT microspheres were prepared by using a spray drying method with thermal calcination. In this composite, the conductive CNT was condensed into the NaTi 2 (PO 4 ) 3 microspheres, leading to intimate interfacial contact between the NaTi 2 (PO 4 ) 3 and CNT. As an anode for energy storage, the NaTi 2 (PO 4 ) 3 @CNT exhibited a high reversible capacity and stable cycling performance due to the constructed 3D network which could greatly enhance the electronic conductivity of NaTi 2 (PO 4 ) 3 material. It delivered the initial capacities of 127, 125 and 123 mA h g −1 at 0.1, 0.2 and 0.5 C, respectively. Even at 10 C, this composite still showed a capacity of 88 mA h g −1 with capacity retention of about 99.3% over 20 cycles.