Facile synthesis and electrochemical characterization of Sn _4Ni _3/C nanocomposites as anode materials for lithium ion batteries

摘要

Sn4Ni _3/C nanocomposites were synthesized by a pyrolyzing-annealing two-step strategy. The phase structure, carbon content and morphology of the nanocomposites were investigated. The results reveal that the crystallinity, carbon structure and purity were enhanced obviously after heat-treatment. Electrochemical performance was evaluated by cyclic voltammograms(CV), galvanostatic discharge/ charge and electrochemical impedance spectra(EIS). The annealed Sn _4Ni _3/C powders deliver an initial charge capacity of 525.2 mA hg ~(-1), 400 mAh g ~(-1)over 10 cycles at 36 mAg ~(-1), 4 300 mAh g ~(-1)after 40 cycles at 72 mAg ~(-1)and maintain 240 mA hg ~(-1)for 40 cycles at 150 mAg -1. TEM investigation of the cycled electrodes shows the discharge/charge process neither destroyed the structure of nanocomposites nor changed the crystallinity of the materials. So the high capacity and stable cyclability are ascribed to the synergetic effect of ductile nickel and conductive carbon constituent and the influence of heat-treatment.