Facile synthesis of hierarchical MoS2/ZnS @ porous hollow carbon nanofibers for a stable Li metal anode.

ABSTRACT

Lithium metal is considered as an ideal anode candidate for next generation Li battery systems since its high capacity, low density, and low working potential. However, the uncontrollable growth of Li dendrites and infinite volume expansion impede the commercialized applications of Li-metal anodes. In this work, we rationally designed and constructed a hierarchical porous hollow carbon nanofiber decorated with diverse metal sulfides (MS-ZS@PHC). This composite scaffold has three advantages First, the synergistic effect of multiple-size lithiophilic phases (nano ZnS and micro MoS2) can regulate Li ions nuclei and grow up homogenously on the scaffold. Second, the enlarged interplanar spacing of MoS2 microsphere on the fibers can provide abundant channels for Li ions transportation. Third, the porous scaffold can confine the volume expansion of Li metal anode during cycling. Therefore, in a symmetrical cell, the MS-ZS@PHC host presents a homogenous Li plating/stripping behavior and runs steadily for 1100 h at 5 mA cm-2 with a capacity of 5 mAh cm-2 and even for 700 h at 10 mA cm-2 with a capacity of 1 mAh cm-2. A full cell using MS-ZS@PHC /Li composite as anode and coupled with LiFePO4 as cathode delivers an excellent cyclic and rate performances.