The fast filling of nano-SnO2 in CNTs by vacuum absorption: a new approach to realize cyclic durable anodes for lithium ion batteries
CNTs filled with amorphous–nanocrystalline SnO2, as a unique SnO2-based nanocomposite structure, were synthesized by a rapid vacuum absorption followed by calcination. The SnO2/CNT nanocomposite anodes had a much higher Li storage capacity than the pristine CNTs, as well as a markedly improved cyclic performance (430 mA h g−1 after 300 cycles at 0.1 A g−1). These superior electrode properties resulted from the unique feature of the amorphous–nanocrystalline mixture of tin oxides stored in the CNT tubes of this nanocomposite, because this structure accommodated the stress and confined the volume change of Li+ insertion/desertion in Sn. Although the nanocomposites had a large initial irreversible capacity loss due to SEI formation, it could be dramatically reduced by prelithiation treatment of the nanocomposite electrode.