Three dimensional topological porous carbon/carbon nanotube/graphene matrix decorated with CoFe alloy for lithium sulfur batteries
Xuan Liu, Zhao Kong, Minmin Yuan, Guanghui Xu, R. Cao, Aiqiang Xu, Peng Wan, Yifeng Xia, Hong Jin, Hui Xu
Abstract
As a potential replacement of lithium-ion batteries (LIBs), lithium-sulfur batteries (LSBs) have high theoretical energy density and long cycle life. However, the poor conductivity of sulfur and Li 2 S 2 /Li 2 S, the shuttle effect of polysulfides and sluggish conversion kinetics have been the hindrance to the development of LSBs. Here, CoFe-nitrogen-doped carbon tubes & hierarchical porous carbon @ graphene oxide (CoFe-NCNT&HC@GO) is proposed to improve the conductivity, mitigate the shuttle effect and enhance the electrochemical kinetics of sulfur electrode. By applying such a three-dimensional topological matrix as a sulfur host and separator modifier, the as-prepared LSB reaches a high capacity of 1130 mAh g −1 after 130 cycles at a current density of 2 A g −1 ; After 500 cycles, the capacity remains around 900 mAh g −1 with an average coulombic efficiency of 99.8 % and a capacity fade rate of 0.062 % per cycle. The results demonstrates that this 3D matrix exhibits strong structural stability, high electrical conductivity , and efficient catalytic ability, and it provides a potential solution for high-performance lithium-sulfur batteries.