Gradient electrospinning and controlled pyrolysis derived FexOy@N-doped carbon nanorods towards enhanced lithium storage

Abstract The rational structural design of the anode material plays a vital role in the performance of lithium-ion batteries (LIBs). Herein, a novel one-dimensional carbon based anode material, consisting of ultra-fine hollow FexOy nanoparticles (NPs) uniformly anchored on the porous N-doped carbon nanorods (donated as FexOy@PN-CNR) has been fabricated via electrospinning technique combined with controlled pyrolysis. Under the Kirkendall-type diffusion, Fe3C is transformed into hollow FexOy NPs. This unique structure could effectively prevent the aggregation, dissolution, and pulverization of iron oxide NPs, maintaining the structural integrity of the electrode. Additionally, it also provides a connected hierarchical conducting network with doped N for electron transport and offers abundant accessible porous channels for fast Li+ diffusion. As a consequence, the resulting FexOy@PN-CNR composite delivers an ultra-high reversible specific capacity of 1198.6 mA h g−1 at 1000 mA g−1 over 100 cycles as anode in LIBs. Remarkably, a stable cycle life (800 mA h g−1 after 200 cycles with a nearly 100% coulombic efficiency) can be obtained even at a large rate of 5000 mA g−1. The present study provides a promising strategy for the construction of nanostructured anode materials toward prominent electrochemical performance of LIBs.