Laser-Triggered High Graphitization of Mo₂C@C: High Rate Performance and Excellent Cycling Stability as Anode of...

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 Mo₂C nanofiber (denoted as laser Mo₂C@C) as the lithium ion battery anode material by laser carbonization of PAN-PMo₁₂ (PAN = Polyacrylonitrile; PMo₁₂ = H₃PMo₁₂O₄₀). The highly graphitized carbon layer in laser Mo₂C@C effectively protects Mo₂C from agglomeration and flaking while facilitating electron transfer. As such, the laser Mo₂C@C electrode displays an excellent electrochemical stability under 5 A g^-1, with a capacity up to 300 mA h g^-1 after 3000 cycles. Furthermore, the extended X-ray absorption fine structure results show the existence of some Mo vacancies in Mo₂C@C. Density functional theory calculations further prove that such vacancies make the defective Mo₂C@C composites energetically more favorable for lithium storage in comparison with the intact Mo₂C.