纳米SnOx的水热合成及其储锂电化学性能

Hydrothermal Synthesis of Nano-SnOx and Its Electrochemical Performance for Lithium-ions Storage

  • 摘要: 采用水热法在不同碱性条件下制备了不同形貌结构的SnO2和SnO纳米材料,研究了两类锡基氧化物作为锂离子电池负极材料的储锂性能. 结果表明: SnCl2·2H2O直接水热水解或在碱性较弱时生成SnO2,当碱性较强(pH>13)时则生成纳米SnO; 与SnO2相比,SnO因其特殊的交叉网状花簇结构,表现出较高的首次充电、放电容量(1 059、1 590 mAh/g,库伦效率66.6%)、循环稳定性(循环500次,可逆容量达315 mAh/g)和倍率稳定性(在2.0 A/g下的可逆容量达到548 mAh/g). 碱性越强,SnO2的循环稳定性和倍率稳定性越好,这归因于碱性越强生成的SnO2颗粒越小,增大了电解液与电极材料的接触面积,缩短了Li+的传输距离,提高了循环稳定性和倍率稳定性. 研究结果为寻找长寿命、高容量负极材料的应用提供了参考.

     

    Abstract: SnO2 and SnO nanomaterials with different morphologies and structures were prepared with the hydrothermal method under different alkalinity conditions, and the lithium-ions storage performance of the two kinds of tin-based oxides as anode materials for lithium-ion batteries was studied. The results showed that SnO2 was formed through direct hydrolyzing of SnCl2·2H2O or when the alkalinity of the solvent was low. Nano-SnO was formed when the alkalinity was high enough (pH>13). Compared with SnO2, SnO had a special cross-network flower-cluster structure, which resulted in higher initial charge and discharge capacity (1 059 and 1 590 mAh/g, with an initial coulombic efficiency of 66.6%), cycle stability (the reversible capacity up to 315 mAh/g after 500 cycles) and rate stability (the reversible capacity up to 548 mAh/g at 2.0 A/g). The higher the alkalinity, the better the cycle stability and rate stability of the synthesized SnO2, which is due to the smaller SnO2 particles generated by the stronger alkaline, which increases the contact area between the electrolyte and electrode materials, shortening the transmission distance of Li+, improving cycle stability and rate stability. The results provide a reference for the application of anode materials with long life and high capacity.

     

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