Sandwiched spherical tin dioxide/graphene with a three-dimensional interconnected closed pore structure for lithium storage
Sandwiched spherical tin dioxide/graphene with a three-dimensional interconnected closed pore structure for lithium storage
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具有三维互连闭孔结构的夹层球形二氧化锡/石墨烯用于锂存储
DOI：
10.1039/c8nr03776k
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发表时间：
2018
期刊：
影响因子：
6.7
通讯作者：
Jiang Yong
中科院分区：
文献类型：
--
作者：
Zhao Bing;Wang Zhixuan;Wang Shanshan;Jiang Jinlong;Si Jian;Huang Shoushuang;Chen Zhiwen;Li Wenrong;Jiang Yong
二氧化锡(SnO2)基复合材料循环性能差的主要原因是锂氧化物(Li2O)的低还原和锡(SnO2)的粗化导致不可逆的容量损失。在本研究中，我们合成了具有三维互联闭孔结构的新型夹心球形二氧化锡/石墨烯。微观结构表征表明，直径为亚微米的球状石墨烯相互连接形成了一个相互连接的柔性导电网络，而大量的SnO2纳米颗粒(约5 nm)均匀地分布在球状石墨烯壳层之间。SnO2/石墨烯的夹层结构和封闭的石墨烯球体可以为SnO2提供双重保护。当用作储能负极材料时，生成的Li2O可以与锡保持密切接触，使转化反应(SnO2+4Li++2E−↔Sn+Li2O)具有很高的原位可逆性，100次循环后可逆性甚至没有明显降低。在100 mA g−1下，夹心球形SnO2/石墨烯复合材料的可逆比容量达到914.8 mA h g−1，明显高于具有开孔结构的SnO2/石墨烯气凝胶。
Low reversion of lithium oxide (Li2O) and the tin (Sn) coarsening causing irreversible capacity loss is the main reason for the poor cycle performance in tin dioxide (SnO2) based composites. In this research, a novel sandwiched spherical tin dioxide/graphene with a three-dimensional interconnected closed pore structure is synthesized. The microstructural characterization shows that the spherical graphene with submicron sized diameters interconnects with each other forming an interconnected flexible conductive network, whereas a large number of SnO2 nanoparticles (approximately 5 nm) are limited homogeneously in between the interlayers of the sphere-like graphene shell. The sandwich structure of the SnO2/graphene and the closed graphene sphere can provide double protection for the SnO2. When it is used as an anode material for energy storage, the generated Li2O can remain in close contact with Sn to make the conversion reaction (SnO2 + 4Li+ + 2e− ↔ Sn + Li2O) highly reversible in situ and the reversibility even does not diminish markedly after 100 cycles. A high reversible specific capacity of 914.8 mA h g−1 is expressed in the sandwiched spherical SnO2/graphene composite at 100 mA g−1 after 100 cycles, which is significantly higher than that of a SnO2/graphene aerogel with an open pore structure.