Heterostructure Mo2C/α-MoO3/G catalyst based heterogeneous catalysis/ deposition mechanism for high-performance Li-S battery

Lithium-sulfur batteries (LSBs) have been recognized as a promising energy device due to their outstanding theoretical energy density and abundant resources. However, the commercial application remains obstruction by the sluggish redox kinetics and serious shuttle effect of polysulfides. Herein, a heterostructural Mo2C/alpha-MoO3/graphene (Mo2C/alpha-MoO3/G) catalyst based on a heterogeneous catalysis/deposition mechanism is proposed to address these issues. The prepared Mo2C/alpha-MoO3/G catalyst is feature with high-activity facet, fast electron delocalization and build-in electric field, which drastically promotes the redox kinetics of polysulfides on the surface of crystal phase. Simultaneously, the heterostructural Mo2C/alpha-MoO3/G catalyst is capable of capturing polysulfides effectively and eliciting the heterogeneous deposition of Li2S on the surface of amorphous phase, of which guarantee the efficient catalytic characteristic during the charge/discharge processes. In addition, the shuttle effect is restricted with a lower shuttle factor (similar to 0.02). Therefore, the assembled LSBs based Mo2C/alpha-MoO3/G catalyst modifying separator exhibits an impressive specific capacity of 1311.4 mAh g(-1) at 0.2 C and excellent rate capability of 580.3 mAh g(-1) at 4 C. More importantly, it demonstrated satisfied cycling stability even at a high sulfur loading mass (4.2 mg(S) cm(-2)) and lean electrolyte conditions (9.3 mu L g(S)(-1)). This work reveals a novel paradigm for optimizing the kinetics behaviors to achieve the commercialization of LSBs.