Performance Enhancement of a Sulfur/Carbon Cathode by Polydopamine as an Efficient Shell for High-Performance Lithium-Sulfur Batteries.

Lithium-sulfur batteries (LSBs) are considered to be among the most promising next-generation high-energy batteries. It is a consensus that improving the conductivity of sulfur cathodes and impeding the dissolution of lithium polysulfides are two key accesses to high-performance LSBs. Herein we report a sulfur/carbon black (S/C) cathode modified by self-polymerized polydopamine (pDA) with the assistance of polymerization treatment. The pDA acts as a novel and effective shell on the S/C cathode to stop the shuttle effect of polysulfides. By the synergistic effect of enhanced conductivity and multiple blocking effect for polysulfides, the S/C@pDA electrode exhibits improved electrochemical performances including large specific capacity (1135 mAh g-1 at 0.2 C), high rate capability (533 mAh g-1 at 5 C) and long cyclic life (965 mAh g-1 after 200 cycles). Our smart design strategy may promote the development of high-performance LSBs.