介孔锡碳复合微球负极材料的原位合成及锂电性能

Preparation and Properties of Mesoporous Sn@C Composite Microspheres Anode Materials for LIB

以五水四氯化锡为锡源,以间苯二酚和甲醛为碳源,采用简单的水热-碳热还原法对其进行原位合成,通过水解-聚合-原位包覆复合,再经高温碳化后成功制备含有介孔结构的Sn@C复合微球材料。结果表明,该Sn@C复合微球材料直径约为1.5μm,分布在碳基体上的Sn颗粒最小约3nm,最大可达20nm;其比表面积为401m2g^(-1),最可几孔径为3.8nm;其首次放电比容量为1237m Ah g^(-1),循环30次后,比容量为470m Ah g^(-1),经过50m A g^(-1)、100m A g^(-1)、200m A g^(-1)、1000m A g^(-1)大电流密度下各循环10次后,放电比容量仍有255m Ah g^(-1),再次返回到50m A g^(-1)时又增至431m Ah g^(-1)。与以二氧化锡为锡源进行简单混合再碳热还原的锡碳复合材料相比,该Sn@C复合微球材料不仅表现出较高的放电比容量,同时也具有较好的循环稳定性能。

Sn@C composite microspheres with mesoporous structure using SnCl_4·5H_2O as a tin source and resorcinol and formaldehyde as a carbon source were synthesized successfully by a simple hydrothermal treatment followed by a subsequent carbonization in nitrogen atmosphere. The results showed that the uniform size of Sn@C composite microspheres was about 1. 5μm,and the Sn particle was about 3 nm - 20 nm. The specific surface area of Sn@C composite microspheres was 401 m-2 g^-1,and the pore size was 3. 8 nm. Its initial discharge specific capacity was 1237 mAh g^-1,and 470 mAh g^-1 was remained after 30 cycles. With increasing the current density from50 mA g^-1 to 1000 mA g^-1,Sn@C composite microspheres can still retain a discharge capacity of 255 mAh g^-1 after 10 cycles. When the current density goes backs to 50 mA g^-1,the discharge capacity reversibly increased to 431 mAh g^-1. Compared to Sn@C composite using SnO_2 as a tin source synthesized by simply mixing followed by a subsequent carbonization,Sn@C composite microspheres showed not only higher discharge specific capacity,but also better cycle stability.