Changming Mao

Polypyrrole-assisted synthesis of roselike MoS2/nitrogen-containing carbon/graphene hybrids and their robust lithium storage performances

Roselike MoS2/nitrogen-containing carbon/graphene (MoS2/NC/G) hybrids were successfully synthesized via a facile polypyrrole (PPy)-assisted hydrothermal approach in combination with high-temperature calcination. The obtained MoS2/NC/G hybrids manifest roselike MoS2 composed of nanosheets coupled uniformly on NC/G nanosheets due to the strong interactions between MoS2 and the abundant nitrogen-containing functional groups of NC. When used as anode materials for lithium ion batteries, the MoS2/NC/G hybrids exhibit enhanced electrochemical energy storage performances compared to the bare MoS2 nanosheets, including high specific capacity (1570.6 mA h g−1 at 0.1 A g−1), excellent rate capability (704.8 mA h g−1 at 5 A g−1) and good cycling stability (96.4% capacity retention after 100 cycles at 0.2 A g−1). The enhanced lithium storage properties of the MoS2/NC/G hybrids can be ascribed to the boosted electronic conductivity arising from the novel hybrid nanostructures of MoS2/NC/G.

Novel Mesoporous Flowerlike Iron Sulfide Hierarchitectures: Facile Synthesis and Fast Lithium Storage Capability

The 3D flowerlike iron sulfide (F-FeS) is successfully synthesized via a facile one-step sulfurization process, and the electrochemical properties as anode materials for lithium ion batteries (LIBs) are investigated. Compared with bulk iron sulfide, we find that the unique structural features, overall flowerlike structure, composed of several dozen nanopetals and numerous small size iron sulfide particles embedded within the fine nanopetals, and hierarchical pore structure features provide signification improvements in lithium storage performance, with a high-rate discharge capacity of 779.0 mAh g−1 at a rate of 5 A g−1, due to effectively alleviating the volume expansion during the lithiation/delithiation process, and shorting the diffusion length of both lithium ion and electron. Especially, an excellent cycling stability are achieved, a high discharge capacity of 890 mAh g−1 retained at a rate of 1.0 A g−1, suggesting its promising applications in lithium ion batteries (LIBs).

Self-polymerized hollow Mo-dopamine complex-induced functional MoSe2/N-doped carbon electrodes with enhanced lithium/sodium storage properties

Self-polymerized hollow Mo-dopamine (PDA-Mo) spherical composites are appealing precursors for constructing robust N-doped carbon-encased Mo-containing electrode materials. Here, a method involving facile chemical precipitation combined with vapor selenization processes has been developed to prepare three-dimensional (3D) hierarchical MoSe2/N-doped carbon microsphere composites. The developed synthetic process eliminates the use of an expensive carbon matrix and toxic reagents, and the preliminary preparation of templates, and is deemed a facile, green, and cost-effective route to fabricate 3D hierarchical architectures. The as-synthesized hierarchical MoSe2/N-doped carbon microsphere composites are constructed from sheet-like MoSe2 layers that are encased by amorphous N-doped carbon. As expected, the as-synthesized 3D hierarchical MoSe2/N-doped carbon microsphere composites have excellent rate capacity (1500 and 600 mA h g−1 at 0.1 A g−1 and 10 A g−1, respectively) and long-life cycling stability (141.7 mA h g−1 remains even after 2000 cycles at 30 A g−1). Besides, the as-synthesized hierarchical MoSe2/N-doped carbon microsphere composites deliver a high capacity of about 570 mA h g−1 at 0.1 A g−1 when used as sodium-ion battery anode materials. Our work provides a successful approach for fabricating 3D hierarchical architectures applying simple synthetic methods, which could shed some light on future research pertaining to the construction of high-performance electrode materials.