Investigation of S/C composite synthesized by solvent exchange method

Solvent exchange method is proposed for the synthesis of sulfur and S/C composite with uniform morphology. SEM, TEM and BET measurements reveal that through this approach, sulfur can subside together with carbon and then form the S/C composite in which sulfur particle is enclosed within the carbon shell even enter into the pores of Printex XE2 carbon. Comparing with sublimed sulfur, the sulfur or S/C composite deriving from the solvent exchange method all shows greatly improved electrochemical performance. Additionally, the influence of solvent on the electrochemical property of the S/C composite is investigated in terms of cycling tests, cyclic voltammetry and impedance measurements. The results show that the S/C composite sample derived from the ultrasonic solvent exchange method in o-xylene solvent has better electrochemical properties than that prepared in CS2. It delivers a capacity of 1173.9 mAh g(-1) in the initial cycle and preserves at 712.5 mAh g(-1) after 50 cycles at 200 mA g(-1). Furthermore, even at a high current density of 1500 mA g(-1), its discharge capacity is well maintained at 529 mAh g(-1) after 50 cycles, which is much higher than the capacity of 293.6 mAh g(-1) for sublimed sulfur electrode. (C) 2012 Elsevier Ltd. All rights reserved.