Sulfur Refines MoO2 Distribution Enabling Improved Lithium Ion Battery Performance

We employ a sulfur-assisted decomposition process to create agglomerates of large (200-500 nm) yet highly nanoporous three-dimensional MoO2 single crystals partially covered with a few atomic layers of MoS2 (MoS2/MoO2 nanonetworks). These materials are highly promising as lithium ion battery anodes. At a current density of 100 mA g(-1), the MoS2/MoO2 nanonetworks exhibit a reversible discharge specific capacity of 1233 mAh g(-1), with only 5% degradation after 80 full charge/discharge cycles. Moreover at the relatively fast discharging rates of 200 and 500 mA g(-1), the capacities are 1158 and 826 mAh g(-1), respectively. A comparison with literature shows that these are among the more promising reversible capacity, cycling capacity, and rate capability values reported for MoO2. The electrochemical properties are attributed to the material's nanoporous crystal morphology that allows for facile reversible transport of Li ions without either disintegration or agglomeration of the structure.