纳米SnO_(x)的水热合成及其储锂电化学性能

Hydrothermal Synthesis of Nano-SnO_(x)and Its Electrochemical Performance for Lithium-ions Storage

采用水热法在不同碱性条件下制备了不同形貌结构的SnO_(2)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:SnCl_(2)·2H_(2)O直接水热水解或在碱性较弱时生成SnO_(2),当碱性较强(pH>13)时则生成纳米SnO;与SnO_(2)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(1059、1590 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,SnO_(2)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SnO_(2)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.

SnO_(2)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 SnO_(2)was formed through direct hydrolyzing of SnCl_(2)·2H_(2)O or when the alkalinity of the solvent was low.Nano-SnO was formed when the alkalinity was high enough(pH>13).Compared with SnO_(2),SnO had a special cross-network flower-cluster structure,which resulted in higher initial charge and discharge capacity(1059 and 1590 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 SnO_(2),which is due to the smaller SnO_(2)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.