Effect of SnO₂-Fe₂O₃ composites on performance of carbon nanotubes current collectors for lithium-ion batteries

The nano-SnO₂-Fe₂O₃ composites were prepared by hydrothermal synthesis method and were used as the active material for lithium-ion batteries. The multi-walled carbon nanotubes (MWCNTs) conductive paper was used as the collector instead of traditional copper foil. The lithium-ion batteries were assembled with SnO₂-Fe₂O₃/MWCNTs conductive paper as anode and metal lithium foil as the counter electrodes. The structure and physical properties of electrodes were characterized by XRD and SEM. The results show that SnO₂-Fe₂O₃ is uniformly intercalated in the bores of the 3D conductive network constructed by MWCNTs. The results of electrochemical tests show that SnO₂-Fe₂O₃/MWCNTs conductive paper electrodes can improve the cycle and rate performance of lithium-ion batteries significantly. The specific capacity of SnO₂-Fe₂O₃/MWCNTs conductive paper electrode can reach 1088 mAh/g at the current density of 100 mA/g after 30 cycles. The specific capacity of SnO₂-Fe₂O₃/MWCNTs conductive paper can maintain at 898 mAh/g with 200 mA/g current density after cycling 200 cycles. The specific capacity of SnO₂-Fe₂O₃/MWCNTs conductive paper decreases with the increase of the current density, but the coulombic efficiency still remain above 96%. While the current increases to 1 600 mA/g, the capacity of SnO₂-Fe₂O₃/MWCNTs conductive paper still maintain at 547 mAh/g. The specific capacity of SnO₂-Fe₂O₃/MWCNTs conductive paper can recover to 1 000 mAh/g while the current reduces to 100 mA/g, and SnO₂-Fe₂O₃/MWCNTs conductive paper exhibit excellent rate performance.