|Other Abstract||With the rapid development of modern society, energy and environment problem have aroused more and more attention, however, new approaches and chances to solve these problems are provided by the fast development of nanoscience and nanotechnology. Manganese oxides with excellent properties have wide applications in various fields, for example, catalysts, absorbers, ion exchange, communication, microwave ferrite, soft magnetic ferrite, gas sensor, humidity sensors and many other fields. Here, our attention is focused on its applications in the following two fields, energy and environmental protection. It does not only has the advantages of low prices, high energy density and high safety, but also has no harm to the environment as the cathode material of lithium-ion secondary batteries. It can also eliminate the electron magnetic pollution caused by various kinds of electronic devices as an microwave absorber, thus purifies the human living environment. Therefore, with the call for environmental protection as the times background, the rapid development of nanoscience and technology as the scientific background and the respect of its applications in the fields of lithium-ion secondary batteries and microwave absorption, the preparation, growth mechanism and morphology control of the low dimensional manganese oxides nanomaterials were investigated. Moreover, its application as microwave absorber was primarily studied which lays a solid foundation for further investigations.
The content, results and originalities of this research are as follows:
1. 3D self-assembled flowerlike hierarchical spheres of MnO2<下标!> and γ-MnOOH nanobelts were prepared by a simple hydrothermal method, using KMnO4<下标!> and H2<下标!>O as reactants, without any templates and surfactants. Morphology and structure of the product were characterized. A growth mechanism was proposed for the first time, which involved two competitive factors, temperature and Coulomb interaction, to understand the formation mechanism of the product. A simple morphology control method to obtain products of uniform morphology and their proportion in the product, which deduced from the proposed mechanism was supported by parallel experiments, thus the morphology of the product can be controlled.
2. Manganese oxde film on Si substrate was obtained by hydrothermal method, using KMnO4<下标!> and H2<下标!>O as reactants, without the assistance of any templates and surfactant...|