氧化锡包裹碳管复合材料的制备及其锂电性能

Preparation and Electrochemical Lithium Storage of Tin Oxide Coated Carbon Nanotube Composites

以分散于十二烷基苯磺酸钠(SDBS)水溶液中的碳纳米管(CNTs)为基体,四氯化锡(SnCl_4)为锡源,硼氢化钠(Na BH4)为还原剂,采用逐层吸附原位沉积工艺制备SnO_2/CNTs复合材料。微观结构显示粒径为2~3 nm的金红石型SnO_2纳米晶均匀包裹在CNTs表面,说明通过在CNTs表面分别吸附BH4-和Sn4+离子,能够有效抑制SnO_2的均相成核-长生,有利于形成同轴结构的SnO_2/CNTs复合材料。该复合材料首次放电容量高达1425.7 m Ah/g,在电流密度为50 m Ah/g时,可逆容量保持在500 m Ah/g,其容量和循环稳定性均优于纯SnO_2。

SnO_2/CNTs nanocomposite was prepared via a layer by layer adsorption and in situ deposition process with SnCl_4 as tin source, Na BH4 as reducing agent and CNTs well dispersed in aqueous solution of SDBS as matrix. Microscopic structure shows that rutile SnO_2 nanoparticles with diameter of 2~3 nm are uniformly coated onto the surface of the CNTs. This reveals that the BH4- and Sn^(4+) ions absorbing onto the surface of CNTs could effectively suppress the homogeneous nucleation and growth of SnO_2, and form uniform SnO_2/CNTs nanocomposite with co-axial structure. The composite delivers a high initial discharge capacity of 1425.7 m Ah/g and its reversible capacity is still as high as 500 m Ah/g at a current density of 50 m Ah/g. The capacity and cycle stability are all better than those of pure SnO_2.