Design Synthesis And Lithium Storage Performance Of Molybdenyl Carbide Anode Materials For Lithium Ion Batteries

Lithium ion batteries（LIBs） have been widely used in electric vehicles, hybrid vehicles and diverse communication equipments due to their advantages of high energy density, large output power and no memory effect. Electrode is the major component of LIBs, which plays a key role in the electrochemical performance of the batteries. Currently, the commercial anode material for LIBs is graphite, which cannot satisfy the increasing demand of electronic equipments, because of its low theoretical capacity. Therefore, researchers all over the world make great efforts to fabricate novel materials with high capacity. Recently, molybdenum carbide has been considered as a promising material for LIBs, due to its excellently chemical stability and high capacity. Besides, the synthesis of nano-sized molybdenum carbide has attracted great attention, owing to its more outstanding electrochemical performance.In this thesis, molybdenum carbide-based nanomaterials were prepared, and their structures were characterized by XRD、XPS、SEM、TEM and other techniques. Then, they were used as electrode materials for LIBs and the electrochemical performance was investigated in details. Our main work is as follows:（1） N-doped Mo₂C/C nanofibers were prepared by an electrospinning approachcoupled with post-pyrolysis.We successfully synthesized N-doped Mo₂C/C nanofibers through a single-nozzle electrospinning method with subsequent heat treatment. This method is very simple and productive. Compared with N-doped carbon nanofibers and bulk Mo₂ C, the N-doped Mo₂C/C nanofibers show excellent cycle performance and rate behavior at both high and low current densities.（2） 3D Mo₂C/C hybrid with a hierarchically porous structure was prepared usingNaCl as a template through freeze-drying treatment followed by subsequentheat treatment.The 3D Mo₂C/C hybrid was prepared from phosphomolybdic acid, citric acid and sodium chloride by a facile freeze drying treatment and subsequent annealing treatment. When applied as anode materials for LIBs, it can deliver a very high specific capacity.