Facile assembly of a S@carbon nanotubes/polyaniline/graphene composite for lithium-sulfur batteries

A carbon nanotube/polyaniline/graphene (MWCNT-PANI-G) composite as sulfur host has been prepared by a simple self-assembly approach with potential application for lithium-sulfur (Li-S) batteries. Scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS) were used to investigate the microstructures and morphology of the as-prepared samples. It is demonstrated that the sulfur can be evenly impregnated into the MWCNT-PANI-G composite with strong chemical bonding. The resultant S@ MWCNT-PANI-G composite with a sulfur content of 68 wt% shows excellent electrochemical performance as cathode for Li-S batteries. It delivers a high initial discharge capacity up to 1290 mA h g(-1), good capacity retention of 784 mA h g(-1) after 100 cycles of charge/discharge at the current density of 330 mA g(-1), and good rate capability of 663 mA h g(-1) and 548 mA h g(-1) at 1.65 and 3.3 A g(-1), respectively. The remarkable electrochemical performances are mainly attributed to the unique architecture of MWCNT-PANI-G with an enhanced electronic and ionic conductivity. Furthermore, this special architecture can provide strong physical and chemical confinement to the active materials and the soluble lithium polysulphides. Therefore, our study demonstrates a facile and low-cost approach to fabricate cathode materials for high-performance Li-S batteries.