Centrifugally Spun Carbon Composite Fibers and Their use as Anode Materials in Lithium-ion Batteries

Abstract

We present results on the centrifugal spinning of Metal-oxides (MOx)/PAN and Metal-Sulfides (MS)/PAN precursors for the mass production of MOx /C and MS/C composite fibers as anode materials for Lithium-ion batteries. MOx and MS such as NiO, TiO2, and SnO2, SnS2 and MoS2 were chosen with carbon as the active materials for the composite-fibers anodes. The microfiber preparation process involved the centrifugal spinning of MOx/MS/PAN precursors into microfibers and subsequent stabilization in air at 280ºC and calcination at 700ºC under Argon atmosphere. The MOx/C and MS/C composite-fibers anodes exhibited a specific capacity between 300 and 1200 mAhg-1 at the first cycle with a high irreversible capacity. The initial high irreversible capacity was attributed to the formation of the SEI layer and the high surface area of the centrifugally spun composite microfibers. In the subsequent cycles, the MOx/C and MS/C composite-fibers anodes exhibited a much stable cycling performance, i.e. 150-600 mAhg-1 was maintained after 100 cycles. The effect of pre-lithiation of the electrode after the first discharge cycle and coating the composite fibers-anode with active materials, prior to cycling, was systematically investigated. The pre-lithiation of carbon composite-fibers anodes after the first cycle exhibited higher charge/discharge capacities and higher coulombic efficiency up to 98% than the pristine carbon composite fibers.