还原氧化石墨烯/碳纳米管/Co_3O_4三元复合材料的制备与电化学性能

Synthesis and electrochemical properties of reduced grapheme oxide/carbon nanotubes/cobaltosic oxide ternary nanocomposite

将低温水热反应和低温热处理相结合,制备了含还原氧化石墨烯(RGO)、碳纳米管(CNTs)和Co3O4的三元纳米复合材料RGO-CNTs-Co3O4;利用X射线衍射仪、扫描电子显微镜、透射电子显微镜分析了合成产物的相组成和微观结构,分析了其形成过程;并利用电化学测试装置测定了其作为锂离子电池负极材料的电化学性能.结果表明,在合成反应过程中,氧化石墨烯被还原剂肼还原为石墨烯,同时在石墨烯和CNTs表面生成氢氧化钴;再经低温热处理得到RGO-CNTs-Co3O4三元复合材料.Co3O4纳米颗粒均匀分散在由RGO片层和CNTs组成的三维网络结构中;这种三维网络结构既有利于电子和离子的传输,又能够有效抑制Co3O4在脱嵌锂过程中因体积变化引起的结构破坏.总体而言,合成的新型三元复合材料具有高的比容量以及良好的循环性能与倍率性能.

Ternary nanocomposite RGO-CNTs-Co3O4 consisting of reduce graphene oxide （RGO）, carbon nanotubes （CNTs）, and cobaltosic oxide （Co3O4） was synthesized by combi- ning low temperature hydrothermal reaction with low temperature treatment method. The phase composition and microstructure of as-prepared product were analyzed by X-ray diffrac- tion, scanning electron microscopy, and transmission electron microscopy, and its formation process was discussed. Besides, an electrochemical test rig was performed to evaluate the elec- trochemical properties of as-synthesized product as an anode material of lithium-ion batteries. Results indicate that, during the synthetic reaction process, reducing agent hydrazine reduces graphene oxide into graphene, and cobalt hydroxide is generated on the surface of RGO and CNTs simultaneously. Resultant cobalt hydroxide in association with RGO and CNTs was then heat-treated at lowered temperatures to afford RGO-CNTs-Co3O4 ternary nanocomposite. Be- sides, Co3O4 nanoparticles are anchored uniformly in the three-dimensional network structure composed of RGO layers and CNTs. The three-dimensional network structure not only helps to promote electron and ion transmission but also can effectively inhibit the structural damage caused by volume changes during insertion and extraction process of lithium-ion. In one word, as-synthesized novel RGO-CNTs-Co3O4 ternary nanocomposite has high specific capacity, ex- cellent cycle stability, and good rate capability.