Lithium Intercalation and Deintercalation Reactions in Synthetic Graphite Containing a High Dispersion of SnO

摘要

SnO-graphite composites containing up to 30 wt % of SnO were prepared by slow hydrolysis of SnCl_2 in the presence of graphite powders. Best application performance was delivered by a composite containing 13.6 wt % of SnO, of which the specific capacity is 450 mAh/g at the C/6 rate and decreases by 12% after 30 cycles. This is a substantial improvement over unsupported SnO which, despite a larger initial capacity (870 mAh/g theoretical), would lose 52% of the capacity in the same number of cycles. In our opinion, the ductility and conductivity of the graphite matrix, a high dispersion of the SnO phase, and the presence of Li_2O barrier layers formed in the first electrochemical decomposition reaction of SnO, work in unison to stabilize Sn microparticles against agglomeration, the established cause of application problems in tin composite oxide based anode materials.