Heterostructured Mo2C–MoO2 as highly efficient catalyst for rechargeable Li–O2 battery

Li–O 2 batteries has been widely investigated for its ultra-high capacity as next generation batteries. Nevertheless, some problems like sluggish kinetic reaction and instability hugely impede the practical use of Li–O 2 batteries. In this work, Mo 2 C/MoO 2 @RGO heterostructures was fabricated by in-situ growth of Mo 2 C between MoO 2 and RGO during calcination and being employed as cathode to explore the synergistic effect in Li–O 2 batteries. As a result, Mo 2 C/MoO 2 @RGO exhibits good specific capacity with 2365 mAh g −1 , high round-trip efficiency (89% at first cycle) and improved cycling performance. Density functional theory calculations indicated that the Mo 2 C/MoO 2 @RGO heterostructures have better capability of oxygen adsorption than sole constituent (Mo 2 C@RGO or MoO 2 @RGO), which triggers the formation of film-like amorphous discharge products, leading to lower overpotential and stable performance. Our study reveals the important role of heterostructures in Li–O 2 batteries system and demonstrates a promising design strategy for heterostructured catalyst.