Metal hydroxide - a new stabilizer for the construction of sulfur/carbon composites as high-performance cathode materials for lithium-sulfur batteries

Rational design and fabrication of advanced sulfur cathodes is highly desirable for the development of high performance lithium-sulfur (Li-S) batteries. Herein, we report Co(OH)(2) as a new stabilizer for the sulfur cathode by constructing a cobalt hydroxide-covered sulfur/conductive carbon black (CCB) electrode with the help of thermal and hydrothermal treatments. In this composite, (Co(OH)(2)@S/CCB), the sublimed sulfur is anchored in the CCB, followed by a uniform coating of Co(OH) 2 nanosheets. As cathode materials of lithium-sulfur batteries, the as-prepared Co(OH)(2)@S/CCB electrode exhibits remarkable electrochemical performances with a high capacity of 1026 mA h g(-1) at 0.1C (1C = 1675 mA g(-1)) and 829 mA h g(-1) at 1C. Moreover, it maintains high coulombic efficiencies above 97% after 200 cycles at 1C, much higher than those of the S/CCB counterpart electrode (85%). After 200 cycles at 1C, a high capacity retention of 71.2% is obtained, better than that of the S/CCB electrode (20.2%). The enhanced performance is mainly due to the Co(OH)(2) layer which helps to inhibit the shuttle diffusion of polysulfides, resulting in improved capacity retention and cycling life.