Fabrication of High Conductive S/C Cathode by Sulfur Infiltration into Hierarchical Porous Carbon/Carbon Fiber Weave-Structured Materials via Vapor-Melting Method

A high-rate sulfur/carbon cathode is prepared by using high conductive hierarchical porous carbon-carbon fiber weave-structured (HPC-CF) materials as carbon host to disperse sulfur. Sulfur is infiltrated into porous carbon with meso/micropores by using an improved vapor-melting adsorption method, which aims to enhance sulfur dispersion and interaction with carbon host. Meanwhile, carbon fiber with weaved structure can connect the dispersed micron S/HPC particles on the current collector. As a result, a highly conductive network around the sulfur particles finally forms in the sulfur/carbon cathode. Results show that improved vapour-melting method can efficiently enhance the sulfur dispersion and interaction with carbon host. Electrochemical measurements show that both of the rate capacity and cycle stability of the sulfur/carbon cathode are significantly improved. It delivers a very high initial discharge capacity of 1692.9 mAh g^-1at 0.1 C, and maintains 1030 mAh g^-1after 130 cycles at 0.5 C. Furthermore, the weave-structured HPC-CF carbon materials increases the conductivity effectively, which enhances the rate performance of the prepared S/HPC-CF cathode. It shows 670.8 mAh g^-1at the first cycle and remains 520 mAh g^-1after 200 cycles at 6.0 C with an average coulombic efficiency of 97.8%. The excellent cycle and rate performance of the prepared S_v-m/HPC-CF can be attributed to the high cathode conductivity, high sulfur utilization and strong interaction between sulfur and the HPC-CF materials. © 2014 Elsevier Ltd.