ZIF-67-derived cobalt-based sulfate CoSO4/carbon nanotube nanocomposites as host material for high-performance lithium–sulfur battery cathode

Lithium-sulfur batteries (LSBs) are considered the most likely replacement for conventional lithium–ion batteries in next-generation high-energy output solutions based on their high specific capacity (1675 mAh g −1 ) and high-energy density (2600 Wh kg −1 ). But, there are some problems that need to be solved urgently. In this work, an environmentally friendly, green, and low-cost ZIF-67-derived cobalt-based sulfate material (CoSO 4 ) combined with carbon nanotubes was proposed as a sulfur host material. Experiments show that the addition of CoSO 4 can significantly enhance the transformation of polysulfide and suppress the shuttle effect. The best performance is the CNT-CoSO 4 -2/S, which has an initial capacity of 1356.9 mAh g −1 at 0.1 C current density. Furthermore, long-term cycle test was carried out at a current density of 0.2 C; the coulombic efficiency was above 98.63% after 200 cycles. This work demonstrates the potential of cobalt-based sulfates as cathode materials for lithium–sulfur batteries.