SnO2-Fe2O3复合材料应用于碳纳米管集流体对锂离子电池性能的影响

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

水热合成法制备纳米SnO2-Fe2O3复合材料,以SnO2-Fe2O3为活性物质,多壁碳纳米管(MWCNTs)导电纸代替传统铜箔作为负极集流体制作锂离子电池。采用XRD、SEM进行表征,结果显示,SnO2-Fe2O3均匀嵌入到MWCNTs构建的三维导电网络的空隙中。电化学测试结果表明,SnO2-Fe2O3/MWCNTs导电纸作为负极电极能够显著提高锂离子电池的循坏和倍率性能。在100mA/g电流密度下循环30次,SnO2-Fe2O3/MWCNTs导电纸电池比容量达到1 088mA·h/g,而在200mA/g电流密度下循环200次后,SnO2-Fe2O3/MWCNTs导电纸比容量能稳定保持在898mA·h/g,表现出良好的循环性能,逐渐增大充放电电流,电池的比容量有所下降但其库伦效率仍然保持在96%以上,而在高倍率(1 600mA/g)下进行充放电时,SnO2-Fe2O3/MWCNTs导电纸比容量仍然能够保持在547mA·h/g,之后再将电流密度降到100mA/g,比容量重新回到1 000 mA·h/g,SnO2-Fe2O3/MWCNTs导电纸表现出十分优异的电化学性能。

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.