Carbon nanotubes modified for ZnCo2O4 with a novel porous polyhedral structure as anodes for lithium ion batteries with improved performances

Abstract

Carbon nanotubes (CNTs) are adopted to modify ZnCo2O4 (ZCO) electrode, and a novel porous polyhedral structure ZCO/CNTs composites are prepared by a facile and scalable hydrothermal process, and the pure ZCO with cubic structure is also synthesized for comparison. The as-prepared materials are characterized by field emission scanning electron microscopy (FESEM). The results demonstrate that the introduced of CNTs has great effects on the nanostructure and electrochemical performance of the samples. The CNTs among the polyhedral structure ZCO/CNTs composites can provide better mechanical robustness, more contact between Li+ and electrodes, and more effective electron transmission than the pure ZCO with cubic structure. When tested as anode materials for lithium ion batteries, the ZCO/CNTs composites exhibit a high initial coulombic efficiency of 83.9%, a high specific capacity of ∼864.6 mAh g−1 at a current rate of 100 mA g−1 after 150 cycles, as well as a good rate capability at elevated current rates, such as, ∼924.3 and ∼605.7 mAh g−1 at current rates of 500 and 2000 mA g−1, respectively. This work would be meaningful in the preparation of complex oxides/carbon composites with porous nanostructure as anodes for LIBs.