Chemical vapor deposition-assisted fabrication of a graphene-wrapped MnO/carbon nanofibers membrane as a high-rate and long-life anode for lithium ion batteries

Abstract

In this work, we have fabricated a graphene-wrapped MnO/carbon nanofibers (MnO/CNFs@G) membrane by a facile electrospinning technique followed by an ambient pressure chemical vapor deposition (APCVD) process. The resultant MnO/CNFs@G membrane with uniform MnO particle distribution in porous carbon nanofibers and with a graphene layer covering not only facilitates the transport of both electrolyte ions and electrons to the MnO surface, but also relieves the pulverization that originated from the large volume change of MnO during the charge/discharge cycles. Interestingly, the free-standing and binder-free MnO/CNFs@G membranes can deliver a high reversible capacity of 946.5 mA h g⁻¹ when the current density is switched back to 0.1 A g⁻¹ after 110 cycles. Even at a high rate (10 A g⁻¹), the electrode can still keep 426.7 mA h g⁻¹ after 5000 cycles with coulombic efficiency of above 99%. This is the best specific capacity and longest cycling life reported for the MnO composite film anodes. We believe that the approach based on CNFs and CVD graphene as a structural support for the transition metal oxide can be potentially extended to improve the electrochemical performance of other electrode materials in lithium ion batteries.