Sulfur encapsulated in a wafer-like carbon substrate with interconnected meso/micropores 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 high electron transport, while the sandwiched porous carbon with a micro/mesoporous structure guarantees fast ion diffusion. Meanwhile, the wafer-like structure enjoys good structural stability and also endows the cathode with a long cycle life. The obtained S/I-rGO-G cathode delivers a high specific capacity of 1138 mA h g−1 at 0.1C, a favorable capacity retention of 600 mA h g−1 after 200 cycles at 1C and a superior rate capability of 638 mA h g−1 at 2C.