Spray deposition of LiMn2O4 nanoparticle-decorated multiwalled carbon nanotube films as cathode material for lithium-ion batteries

We prepared LiMn2O4 nanoparticle-decorated multiwalled carbon nanotube (MWCNT) films as a cathode electrode for lithium-ion batteries using a spray-deposition method. The surface morphologies and structures of the films were characterized using scanning electron microscopy and X-ray diffraction analysis. The results revealed that fairly homogeneous spinel LiMn2O4 nanopowder-based films with the grain size of 20-50 nm were successfully formed on the surface of the MWCNTs. Cyclic voltammetry confirmed the presence of typical spinel LiMn2O4 structure on the MWCNTs with showing stronger oxidative peaks of better reversibility as compared to a pure LiMn2O4 electrode. The spray-deposited LiMn2O4-decorated MWCNT film was also found to have a higher discharge capacity (97.2 mAh/g) than the as-deposited LiMn2O4 film (75.2 mAh/g) as well as excellent cycling stability. These characteristics are due to the fact that MWCNTs provide the cathode with multiple electron tunneling pathways and a mechanically strong framework.