Binder-free polymer encapsulated sulfur-carbon nanotube composite cathodes for high performance lithium batteries

Binder-free polymer encapsulated nano sulfur/super-aligned CNT (PVP@S-SACNT) composite electrode is developed via a solution-based method. In the composite structure, PVP not only facilitates better dispersion of SACNT bundles into a 3D continuous network, but also encapsulates the sulfur nanoparticles onto the SACNT network to ensure their tight electrical connection and prevent polysulfide dissolution. Combining the advantages of the high conductive and porous SACNT network and the PVP surface modification, the PVP@S-SACNT cathode exhibits excellent cyclic stability (initial capacity of 1303 mA h g(-1), and 856 mA h g(-1), after 200 cycles at 1 C) and high-rate performance (590 mA h g(-1), at 20 C). Moreover, the PVP@S-SACNT composite presents excellent long-term capacity stability with a capacity decay of 0.052% per cycle during 1000 charge/discharge cycles at 2 C. With these appealing performances, the PVP@S-SACNT composite becomes a promising cathode material for the next-generation rechargeable batteries. (C) 2015 Elsevier Ltd. All rights reserved.