In-situ topochemical nitridation derivative MoO2–Mo2N binary nanobelts as multifunctional interlayer for fast-kinetic Li-Sulfur batteries

Abstract

Li-Sulfur batteries (LSBs) have a wide application foreground for its high energy density and low-cost, however, the shuttle effect, volume fluctuation and irregular Li2S deposition on the cathode side often result in severe capacity decaying during its cycles. It is necessary to design and optimize the conversion route from sulfur (S8) to lithium sulfide (Li2S) to improve the reversibility of Li–S battery. Herein, novel MoO2–Mo2N binary nanobelts synthesized from α-MoO3 through an in situ topochemical nitridation process were employed as the highly efficient interlayer material for LSBs, which not only acted as a physical barrier to alleviate the shuttle effect but also regulated the conversion of lithium polysulfides (LiPSs) across the interface and optimized the nucleation of solid Li2S during cycling. Combining the polarity of MoO2 with the conductivity of Mo2N, such hybrid structure exhibited excellent cycling stability with a very low capacity decay of 0.028% per cycle up to 500 cycles at 1C. Even under the high areal sulfur loadings of 3.1 and 4 mg cm−2, the high discharge capacity and excellent capacity retention ratio can also be obtained. The concept of in-situ binary heterogeneous interfaces construction might also be used in the design and preparation of other electronic devices.