Polyoxometalates Modified Carbon Nanotubes As Anode Materials For Lithium Ion Battery

Polyoxometalate is a polyatomic ion, usually an anion, that consists of three or more transition metal, usually group 5 or group 6 transition metals in their high oxidation states (V, Ni, Mo or W), oxyanions linked together by shared oxygen atoms to form a large molecule. The framework of transition metal oxyanions may enclose one or more heteroatoms such as phosphorus or silicon, themselves sharing neighbouring oxygen atoms with the framework. The huge range of size, structure and elemental composition of polyoxometalates leads to a wide range of different properties which make them as good candidates in many fields. However, the unfunctionalized polyoxometalates are crystalline solids which are difficult in processing. Therefore, functionlized POM into organic-inorganic hybrids provide various option for easier integration of POMs into multi-functional architectures and materials. Carbon nanotubes as a kind of ID nano-materials possess many outstanding properties, such as extraordinary thermal and electrical conductivity and mechanical propertiers, which make them valuabe for nanotech electronics, optics and other fields of materials science and technology. Meanwhile, the ID structure and easily functionalized surface of carbon nanotubes make them as great substrate for composite materials. Multi-functional materials assembled from modiefing post-functionalized POMs onto carbon nanotube may be a kind of potential electrode materials in the fields of energy storage and conversion.In this work, two kinds of organic functional groups covalently tethered polyoxometalates have been prepared and characterized (denoted as Mn-Anderson-Pyrene and Si-Keggin-NH2, respectively). The resulting compounds have been characterized by FT-IR, TGA, XPS. Two different strategies, non-covalent method via π-π stacking and covalent method via amide bond, have been empolied in the process of modifying the post-functionalized POM onto carbon nanotubes to form the multi-functional nanohybrid materials. The hybrid materials have an excellent performance as anode in the lithium ion battery.