Three-Dimensional Hierarchical Constructs of MOF-on-Reduced Graphene Oxide for Lithium-Sulfur Batteries

A three-dimensional (3D) hierarchical MOF-on-reduced graphene oxide (MOF-on-rGO) compartment was successfully synthesized through an in situ reduced and combined process. The unique properties of the MOF-on-rGO compartment combining the polarity and porous features of MOFs with the high conductivity of rGO make it an ideal candidate as a sulfur host in lithium-sulfur (Li-S) batteries. A high initial discharge capacity of 1250 mAh g^-1 at a current density of 0.1 C (1.0 C=1675 mAh g^-1 ) was reached using the MOF-on-rGO based electrode. At the rate of 1.0 C, a high specific capacity of 601 mAh g^-1 was still maintained after 400 discharge-charge cycles, which could be ascribed to the synergistic effect between MOFs and rGO. Both the hierarchical structures of rGO and the polar pore environment of MOF retard the diffusion and migration of soluble polysulfide, contributing to a stable cycling performance. Moreover, the spongy-layered rGO can buffer the volume expansion and contraction changes, thus supplying stable structures for Li-S batteries.