Synergistic Construction of Efficient Heterostructure Electrocatalysis for High-Performance Lithium-Sulfur Batteries

Since a sluggish conversion reaction and shuttling of polysulfides have been barriers to high-performance Li-S batteries, it is particularly critical to establish nanostructured electrocatalysts with high specific surface area and electron conductivity, an excellent anchoring capability, and long-term durability. Herein, a robust binary synergistic MoS2/MXene heterostructure is proposed by the homogeneous growth of MoS2 on an MXene substrate. Due to the hierarchical structure and strong interfacial coupling effect, the binary synergistic MoS2/MXene heterostructure not only suppresses the restacking of MoS2 and MXene nanosheets but also provides abundant active sites to capture polysulfides and catalyze its conversion reaction. Typically, polysulfides are immobilized by MoS2 nanosheets; then, the anchored polysulfides are rapidly transferred from MoS2 to MXene via heterointerfaces. The MXene surface is endowed with abundant oxygen terminations, which accelerates the polysulfide conversion kinetics to a great extent. Therefore, the assembled Li-S battery delivers a reversible capacity of 981 mA h g-1 at 0.5 C after 300 cycles. Even at high rate of 5 C, capacity is still maintained at an excellent level of 408 mA h g-1 after 500 cycles with a Coulombic efficiency of 96.5%. Even more fascinating, at 0.2 C, the MoS2/MXene cathode can realize a high sulfur loading of 4.0 mg cm-2 and with capacities of 608 mA h g-1 over 500 cycles, which will promote the practical applications of Li-S batteries.