High-rate capability of three-dimensional CNTs-decorated NaTi2(PO4)3@C microspheres for sodium energy storage

Abstract

One of the newest materials for sodium energy storage is NaTi 2 (PO 4 ) 3 , which is widely researched due to its considerable Na + conductivity and excellent safety characteristics. However, NaTi 2 (PO 4 ) 3 exhibits unfavorable electronic conductivity, restricting its application in sodium-ion batteries. Herein, three-dimensional CNTs-modified NaTi 2 (PO 4 ) 3 @C microspheres were synthesized by spray-drying method and solid-state high-temperature annealing. Within the designed composite, the NaTi 2 (PO 4 ) 3 @C nanoparticles were uniformly fixed on the CNTs surfaces, forming a three-dimensional CNTs-NaTi 2 (PO 4 ) 3 @C architecture. As an anode in a sodium-ion battery, the resulting CNTs-NaTi 2 (PO 4 ) 3 @C exhibited exceptional sodium storage potential, with a high reversible capacity, stable cycling properties, and a good rate capability. An excellent discharge capacity of about 128.5 mAh g -1 was achieved with a low rate of 0.1C, and the anode displayed a reversible capability of 75.8 mAh g -1 at 20C over 1000 cycles, with a low capacity fading rate of about 0.011% per cycle. Therefore, this novel strategy is highly effective and can be adopted to enhance the battery properties of other electrode materials.