Heterostructure design of Fe2(MoO4)3 decorated MoO3 nanorods for boosting catalytic activity in high-performance lithium sulfur batteries

Abstract

Lithium sulfur (Li–S) batteries have been intensively studied as promising energy storage devices due to their high theoretical specific capacity and cost effectiveness. However, the poor cycle life and low Coulombic efficiency caused by the insulating nature of sulfur and shuttle effect of lithium polysulfides (LiPSs) still hinder the practical implementation of Li–S batteries. Here, we report Fe2(MoO4)3 decorated MoO3 nanorod (FMMO–NR) heterostructure as an efficient catalytic host for Li–S batteries. Fe2(MoO4)3 has low electrical conductivity, but excellent catalytic activity, and MoO3 has high electrical conductivity but low catalytic activity. With the synergistic advantages of the high electrical conductivity of one-dimensional MoO3 nanorod and strong catalytic activity of Fe2(MoO4)3 with a redox potential of ∼2.9 V, FMMO–NR enables fast conversion reactions of long-chain LiPSs to Li2S2/Li2S and suppresses the shuttle effect by immobilization of LiPSs with strong binding. The FMMO–NR electrode shows a high discharge capacity of 1588 mAh g − 1 and stable cycle performance with a capacity retention of 70% at 2 C over 500 cycles. Even with a high sulfur loading of 5 mg cm–2, the FMMO–NR electrode presents outstanding cycling stability with a capacity retention of 73% over 100 cycles.