Fluorinated multiwall carbon nanotubes for high rate lithium ion primary batteries

Fluorinated graphite (F-graphite) and multiwall carbon nanotubes (F-MWCNTs) were synthesized by direct fluorination with fluorine gas and used as the cathode materials of lithium primary batteries. Their microstructures were characterized by SEM, TEM, XRD and XPS. Results show that the F-MWCNTs have a core-shell structure with the outer layers fluorinated while the inner ones retain their pristine graphitized structure. A F-MWCNT electrode exhibited a higher discharge capacity and a higher discharge plateau than a F-graphite electrode at the same C rates. The discharge capacities of the F-MWCNT and F-graphite electrodes reached 822 and 786.1 mAh/g at 0.05 C, respectively. The corresponding values reached 375.4 and 283.7 mAh/g at 2 C, indicating an excellent rate performance for the former.