Electrospun Na<sub>3</sub>V<sub>2</sub>(PO<sub>4</sub>)<sub>3</sub>/C nanofibers as self-standing cathode material for high performance sodium ion batteries
Longlong Luo, Bin Cheng, Yuxin Chen, Shaojun Chen, Guanlun Liu, Haitao Zhuo
Abstract
Abstract This work focuses on the preparation of a 3D flexible Na 3 V 2 (PO 4 ) 3 /C fiber membrane, as self-standing cathode for Na-ion batteries, via a facile and simple electrospinning method, is followed by a hot-pressing process. A series of heat treatment temperatures are studied in detail, it is found that the temperature of the thermal process is a key parameter for controlling the structural organization of the material, as well as the size and dispersion of Na 3 V 2 (PO 4 ) 3 nanoparticles on the carbon surface. Hence, Na 3 V 2 (PO 4 ) 3 nanoparticles, with a size of 40 nm and highly disperse on the carbon nanofibers, are obtained after calcination at 800 °C. In addition, this sample (Na 3 V 2 (PO 4 ) 3 /C Nanofiber-800) exhibits the best electrochemical performances among all the samples. For instance, it displays a considerably high initial discharge capacity of 109, 84, 77, and 71 mA h g −1 at a current density of 0.1, 10, 20, and 30 C, respectively. Moreover, the Na 3 V 2 (PO 4 ) 3 /C Nanofiber-800 shows notable cycle stability with about 95.3% capacity retention of its initial capacity after 1000 cycles at 2 C, These high performances is attributed to the unique nanofiber structure and uniform distribution of Na 3 V 2 (PO 4 ) 3 nanoparticles in the highly conductive carbon matrix.