Sulfur Encapsulated in Wafer-like Carbon Substrate with Interconnected meso/micro Pores for High-Performance Lithium-sulfur Batteries

Porous carbon materials have been regarded as attractive hosts for lithium sulfur batteries. However, the electron conductivity and Li+ ion diffusion need to be enhanced due to the low graphitization and the restricted ion transport. In order to improve the rate capability and cycling stability of the cathode, we propose a wafer-like structure to realize the high conductivity and structural stability of the porous carbon substrate. The graphene layers ensure the high electron transport, while the sandwiched porous carbon with micro/meso porous structure guarantees the fast ion diffusion. Meanwhile, the wafer-like structure enjoys well structural stability and also makes the cathode with long cycle life. The obtained S/I-rGO-G cathode delivers a high specific capacity of 1138 mA h g-1 at 0.1 C, a favorable capacity retention of 600 mA h g-1 after 200 cycles at 1 C and a superior rate capability of 638 mA h g-1 at 2C.