Amorphous Cu-added/SnOx/CNFs composite webs as anode materials with superior lithium-ion storage capability

Amorphous Cu-added tin oxides/carbon nanofiber (Cu-added SnOx/CNFs) composite webs used for lithium-ion battery anode materials are prepared by an electrospinning technique and subsequent thermal treatment. The Cu-doped SnOx particles are uniformly distributed in the CNFs and maintain the original morphology after long-term cycling. In a controlled experiment, SnOx-20%Cu/CNFs with an atomic ratio of Cu : Sn = 0.2 shows the highest electrochemical performance with a high reversible capacity of 743 mA h g−1 at a current density of 200 mA g−1 and an excellent rate capacity of 347 mA h g−1 at 5 A g−1. Moreover, the composite electrode exhibits an outstanding long-term cycling performance at 2 A g−1 even after 1000 cycles. The superior reversible lithium-ion storage capability is attributed to the uniform dispersion of the Cu2O and ultrafine SnOx particles in CNFs as well as the Cu-addition effects such as promoting electron transport and Li+ diffusion, preventing Sn from aggregation during cycling, and improving the reversibility of Sn back to SnOx in the recharge process.