Controllable SnO2/ZnO@PPy hollow nanotubes prepared by electrospinning technology used as anode for lithium ion battery

Abstract

The one-dimensional hollow nanostructure can effectively decrease the diffusion distance of lithium ions and alleviate the volume change of SnO2 during cycling. In this work, SnO2/ZnO hollow nanotubes were obtained from two different molecular weights of Polyvinylpyrrolidone (PVP) by combining electrospinning technology and heat treatment. Mechanism studies indicated the hollow nanotubes with different morphology could be controllable by varying the molecular weight of PVP. SnO2/ZnO nanotubes with high molecular weight PVP as precursor (SnO2/ZnO–H) had smaller diameter and denser structure, which as anode showed better stability and capacity in electrochemical test. The conductivity and stability of SnO2/ZnO–H were further improved after coated with Polypyrrole (PPy) by the in-situ polymerization. The reversible capacity of the batteries was improved, and the volume expansion of the metal oxide was restrained during charging and discharging. The SnO2/ZnO@PPy anode exhibited a high discharge capacity of 626.1 mA h g−1 of 0.2C after 100 cycles, showing an outstanding stability. Therefore, controllable hollow metal oxide nanotubes structures could be obtained via different the molecular weights of precursor polymer. And the hollow nanotubes after coating by PPy as anode materials exhibited the excellent electrochemical performance. This research provided an idea in further design and optimization of anode microstructure for lithium-ion batteries.