Electrochemical performance of TiNb2O7 nanoparticles anchored with different contents of MWCNTs as anode materials for Li-ion batteries

In this study, the electrochemical behavior of titanium niobium oxide (TNO) composites with 1, 3, and 5 wt.% of multi-walled carbon nanotubes (MWCNTs) was investigated. The results showed a significant improvement in the electrochemical performance of TNO by the addition of MWCNTs in terms of initial capacity, rate performance, and rate capability. The initial capacity of pure TNO at 0.1C increased from 251.6 mAh/g to 272.4, 302.2, and 265.9 mAh/g by addition of 1, 3, and 5 wt.% of MWCNTs, respectively. Furthermore, the cyclic stability of the samples improved considerably by the addition of the MWCNTs; the capacity value of pure TNO after 200 cycling at 1C was only 78.3 mAh/g while for TNO/3 wt.% MWCNTs was about 145.6 mAh/g. Similarly, the rate performance of the TNO/MWCNTs nanocomposites was better than pure TNO in all charge/discharge rates. The MWCNTs contents in nanocomposites had significant effects on their performance in which the optimal content of MWCNTs in this study was 3 wt.%. The results showed that the presence of MWCNTs in nanocomposites created a conductive network with good ionic and electrical conductivity and thus, improved the rate performance of samples. In addition, the stresses caused by the intercalation/deintercalation of Li-ions were moderated by MWCNTs, improving the cyclic stability.