模板剂F127对介孔SnO2的孔结构及电化学性能的影响

以SnCl₄·5H₂O和尿素为原料, 嵌段聚醚F127(EO₁₀₆-PO₇₀-EO₁₀₆)为模板剂, 通过水热法制备了介孔SnO₂材料。XRD、TEM和BET等分析结果表明, 模板剂F127添加量对介孔SnO₂的孔结构有重要影响。F127添加量增加, SnO₂比表面积增大, 孔容增大, 孔径分布变宽。电化学测试结果表明, 介孔的存在不仅能为锂离子脱嵌提供通道, 而且可以缓冲SnO₂的体积膨胀, 从而提高介孔SnO₂负极材料的电化学性能; 当F127添加量为6.0 g时, 所制备SnO₂具有124 m²/g的比表面积, 平均孔径为4.94 nm, 表现出最佳的循环性能和倍率性能, 在60 mA/g的电流密度下经30次循环后, 其可逆容量仍保持在434 mAh/g; 循环伏安测试表明部分高活性Li₂O的可逆还原提供了附加的可逆容量。

F127 Template on Pore Structure and Electrochemical Performances of Mesoporous SnO2

Mesoporous SnO₂ was synthesized via a hydrothermal process using tin chloride (SnCl₄·5H₂O) and urea ((NH₂)₂CO) as raw materials, with a block polyether F127(EO₁₀₆-PO₇₀-EO₁₀₆) as a template. The analysis results (XRD, TEM, BET, etc) show that the amount of F127 has significant influence on pore structure of mesoporous SnO₂. With increasing dosage of F127, specific surface area and pore volume of the mesoporous SnO₂ increase with pore size distribution relatively broad. The results of the electrochemical tests indicate that existence of mesopores not only provide the path for deinsertion and insertion of Li⁺, but also buffer the huge volume expansion of tin dioxide, which consequently improves the electrochemical performances of mesoporous SnO₂ as an anode material. When the amount of F127 is 6.0 g, the as-prepared 6F-SnO₂ with a BET specific surface area of 124 m²/g and average pore size of 4.94 nm, displays optimal cycle performance and rate performance which the reversible capacity of the 6F-SnO₂ maintains 434 mAh/g at 60 mA/g after 30 cycles. In addition, the cyclic voltammetric test reveals that the reversible reduction of partial Li₂O with high activity can provide additional reversible capacity.