Fluoride-assisted coaxial growth of SnO2 over-layers on multiwall carbon nanotubes with controlled thickness for lithium ion batteries
Fluoride-assisted coaxial growth of SnO2 over-layers on multiwall carbon nanotubes with controlled thickness for lithium ion batteries
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DOI：
10.1039/c3ce41808a
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发表时间：
2014
期刊：
影响因子：
3.1
通讯作者：
Zhenzhen Lu;Hongkang Wang
中科院分区：
文献类型：
--
作者：
Zhenzhen Lu;Hongkang Wang
我们报道了一种简便的策略，通过水热法，以氟化钠作为形貌控制和导向剂，在具有分级结构且厚度可控的多壁碳纳米管（MWCNTs）上同轴生长致密的二氧化锡覆盖层。通过调节碳纳米管与锡前驱体的比例，二氧化锡覆盖层的厚度可以从几十纳米控制到几纳米。当用作锂离子电池的负极材料时，同轴生长有薄（约10纳米）二氧化锡覆盖层的碳纳米管在50次循环后显示出可逆容量为431毫安时每克的储锂性能，这比厚（约55纳米）二氧化锡覆盖层或碳纳米管与分离的二氧化锡纳米颗粒的混合物的性能要好两倍。循环性能的提高归因于团聚减少、电子导电性增强以及在锂嵌入/脱嵌过程中内部应力的释放。
We report a facile strategy to coaxially grow compact SnO2 over-layers on multiwall carbon nanotubes (MWCNTs) with hierarchical structures and controlled thickness via a hydrothermal method, using NaF as a morphology controlling and directing agent. The thickness of the SnO2 over-layers can be controlled from several tens of nanometers down to several nanometers by adjusting the ratio of carbon nanotubes to Sn precursor. When applied as anode materials for lithium ion batteries, carbon nanotubes with coaxially grown thin (~10 nm) SnO2 over-layers showed lithium storage performance with a reversible capacity of 431 mA h g−1 after 50 cycles, which is two times better than that of thick (~55 nm) SnO2 over-layers or mixtures of carbon nanotubes and separated SnO2 nanoparticles. The improved cyclic performance was attributed to reduced agglomeration, enhanced electronic conductivity and released internal strain during the lithium insertion/extraction.