Effects of manganese acetate on the anodic performance of carbon nanotubes for Li ion rechargeable batteries

Effects of the addition of various manganese compounds on anodic performance of carbon nanotube were investigated. It was seen that the Li intercalation capacity decreased drastically by the addition of most manganese compounds. However, addition of Mn(CH3COO)(2) greatly improved the capacity for Li intercalation. Li intercalation capacity increased with increasing Mn(CH3COO)(2) concentration and the largest capacity of 360 and 330 mAh/g for the insertion and reversible Li intercalation was achieved when 1 wt.% Mn(CH3COO)(2) was added. The increased capacity was sustained after 50 times of charge and discharge cycles. X-ray absorption near edge spectra (XANES) suggests that the state of added Mn ion is close to MnO2 and so the added Mn(CH3COO)(2) decomposed during preparation. The surface organic layer formed by the acetic acid appears to give a superior solid electrolyte interface (SEI). The positive effects of Mn(CH3COO)(2) are obtained only when manganese ion and acetic acid coexist. Therefore, it is believed that the coexisting Mn ion works as a catalyst for the decomposition of acetic acid. (C) 2003 Elsevier Science B.V. All rights reserved.