Nanotubes as Anode Material for Lithium-ion Batteries

Abstract

Carbon nanotubes including arc multi-walled nanotubes (arc-MWNT), arc- and laser-produced single-walled nanotubes (SWNT), and catalytically grown multi-walled nanotubes (vapor grown, VG, and chemical vapor deposited, CVD MWNT) were investigated as anode materials for lithium ion intercalation and de-intercalation. As-produced arc-MWNT deliver capacity in the range of 190–210 mAh/g and an irreversible capacity in the range of 90 to 140 mAh/g. The reversible capacity improved to 310–340 mAh/g with purification and opening of the ends of the tubes. SWNT delivered relatively high reversible capacity of over 600 mAh/g but they were associated with very high irreversible capacity (∼200%) that makes these materials impractical to use as an anode material for lithium batteries. VG nanofibers exhibited poor reversible capacity and also very high irreversible capacity. On the other hand, CVD MWNT delivered over 400 mAh/g reversible capacity with relatively low irreversible capacity (<25%). Further work will be needed to optimize these promising materials.