Laser-Triggered High Graphitization of MoC@C: High Rate Performance and Excellent Cycling Stability as Anode of Lithium Ion Batteries.

Fast electron/ion transport and cycling stability of anode materials are key factors for achieving a high rate performance of battery materials. Herein, we successfully fabricated a carbon-coated MoC nanofiber (denoted as laser MoC@C) as the lithium ion battery anode material by laser carbonization of PAN-PMo (PAN = Polyacrylonitrile; PMo = HPMoO). The highly graphitized carbon layer in laser MoC@C effectively protects MoC from agglomeration and flaking while facilitating electron transfer. As such, the laser MoC@C electrode displays an excellent electrochemical stability under 5 A g, with a capacity up to 300 mA h g after 3000 cycles. Furthermore, the extended X-ray absorption fine structure results show the existence of some Mo vacancies in MoC@C. Density functional theory calculations further prove that such vacancies make the defective MoC@C composites energetically more favorable for lithium storage in comparison with the intact MoC.