Se/CNTs microspheres as improved performance for cathodes in Li-Se batteries

CNTs microspheres were prepared by an ultrasonic spray method, selenium was subsequently loaded by molten diffusion strategy. The prepared Se/CNTs microspheres were characterized by X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy (SEM) including elemental mapping analysis, transmission electron microscopy (TEM), and thermogravimetric analysis (TGA). The CNTs are entangled into CNTs microspheres of uniform size and full of micropores, effectively increases the loading of selenium. Se/CNTs microspheres exhibit the initial capacity of 626 mAh g⁻¹ at 0.2 C rate (1 C = 675 mA g⁻¹), the capacity of 390 mAh g⁻¹ at 5 C rate, and capacity retention of 80% after 500 cycles at 1 C rate. These excellent properties indicate that the Se/CNTs microspheres material is a potential material for Li-Se batteries.