二氧化锡/碳纳米管纳米复合材料的制备及电化学性能

Preparation and Electrochemical Performance of Tin Oxide/Carbon Nanotube Nanocomposites

目前,用于商业锂离子电池的负极材料主要为石墨材料,实际上二氧化锡(SnO2)的理论容量远大于石墨,但是,其能形成大的首次不可逆容量及由锂锡合金引起的体积膨胀而造成低的容量保持率。碳纳米管(MWCNTs)与石墨相比,碳纳米管不仅具有更高的容量也可以被用作基体框架形成金属与碳管复合材料,这样既可以利用金属的高容量性能,也可以防止其粉化。本实验主要采用化学沉积法制备SnO2/MWCNTs纳米复合材料,二氧化锡可以沉积在碳纳米管的内部和表面。研究MWCNTs的含量及管径大小对SnO2/MWCNTs纳米复合材料的结构和性能的影响,证实其的确对锂离子电池的可逆容量和循环稳定性有着很大的影响。

Anode materials in many commercial lithium-ion batteries are composed of graphite. In fact, theoretical capacities of SnO2 are far greater than that of graphite. But it also results in a large initial irreversible capacity and a poor capacity retention due to the volume expansion/contraction of Sn during alloying/dealloying reactions with Li+. MWCNTs not only have a higher capacity than graphite, but also they can be used as a support matrix forming novel metal/MWCNT composites which can take advantage of the higher capacity of metals and prevent the problem of pulverization too. In this work, SnO2/MWCNTs nanocomposites were fabricated by chemical deposition method.SnO2 nanoparticles can be deposited on the outside and inner surfaces of the MWCNTs. It was proved that the content and inner diameter of MWCNTs in the nanocomposite electrodes indeed played a dominant role in improving the reversible capacity and cycling stability of lithium-ion batteries.