Vertically aligned, polypyrrole encapsulated MoS2/graphene composites for high-rate LIBs anode

Ultrathin MoS2 nanosheets were vertically anchored on the reduced graphene oxide (MoS2/rGO) via hydrothermal method. To further engineering the surface conductivity, ultrathin polypyrrol (PPy) layer was coated on the MoS2/rGO composite via in situ polymerization to form a bi-continuous conductive network with a sandwich-like structure. The graphene nanosheets and the PPy coating can facilitate the electrons transfer rate, while the ultrathin MoS2 nanosheets can enhance the utilization efficiency of the active materials. The obtained MoS2/rGO-10 composite exhibits high reversible specific capacity (970 mAh g−1 at 0.1 A g−1) and rate capability (capacity retention of 64% at 3.2 A g−1). Moreover, the PPy@MoS2/rGO hybrids reveal lower specific capacity but better rate capability, and a “trade-off” effect between electrons and ions transfer resistance was observed. This easy-scalable PPy surface conductivity engineering strategy may be applied in the preparation of high-performance LIBs active materials.