Dual regulation mechanism of MoS2/MoO3 heterostructure for polysulfide and volume effect enables stable and durable lithium storage

Current commercial Li-ion batteries (LIBs) with graphite anode are unable to meet the actual demand due to their low energy density. Recently, MoO3 possesses 1117 mAh g-1 high theoretical specific capacity has received a wide attention and is regarded as a promising anode material. However, the low intrinsic electronic conductivity and the large volume effect of MoO3 limited the practical application. Given the typical MoS2 anode materials with high electron conductivity and discharge capacity, in this work, we designed a 2D hierarchical MoS2/MoO3 nanocomposite. As expected, the large exposed edges and layered MoS2 provide sufficient channels for rapid ion diffusion while improving the volume variation and conductivity of MoO3. Nevertheless, as an anode material, MoS2 suffers from severe and undesired sulfur loses during cycling, resulting in rapid capacity degradation. It is found that MoO3 and intercalation state (LixMoO3) characters a strong chemical adsorption property that have been demonstrated to be effectively promoting the conversion of soluble lithium polysulfides, thereby enhancing the kinetics of sulfur conversion. Inspired with such multifunction structural design strategy, the MoS2/MoO3 anode achieves a remarkable specific capacity (1255.7 mAh g-1) and long cycling life (1300 cycles). Subsequently, coupled with LiFePO4 cathode, the full cells achieved a 129 mAh g-1 competitive capacity and the retention rate is as high as 99.3% after 100 cycles. This work provides an inspired strategy and routes to realize a high energy density LIBs.