Carbon Nanotube-Based Sulfur Cathode with a Mesoporous Carbon-Silica Composite for Long Cycle Life Li-S Batteries

The use of carbon nanotube (CNT) films as a sulfur host is a promising approach to improve the sulfur loading and energy density of Li-S batteries. However, the inability to durably incorporate polysulfides within the cathode structure results in a limited cycle life. Herein, we propose a CNTbased sulfur cathode with carbon-coated ordered mesoporous silica (c-OMS) to overcome the cycle performance issue. Scanning electron microscopy and X-ray diffraction studies on the c-OMS prepared in this work revealed that the wall surface of OMS was evenly coated with an extremely thin carbon layer. The sulfur-CNT cathode with c-OMS retained a remarkably improved capacity (942 mAh g^-1) with excellent cycling stability (91%) after 100 cycles as well as significantly high sulfur utilization in the first cycle compared with the sulfur-CNT cathode with OMS. This result may stem from the surface property of c-OMS with high chemical affinity towards electrolyte solvents.