Study On Chemical Synthesis And Energy Storage Properties Of Transition Metal Compounds Nanomaterials

The world’s energy crisis and environmental pollution is more and more serious, and the development of new energy materials is an effective way to solve the energy crisis and environmental pollution. Wherein, the transition metal compounds have peculiar physical and chemical properties, because it’s special outer valence electrons structure, so that in the field of catalysis, electrochemistry, sensing, magnetic and adsorption have a wide application. Recently, the transition metal compounds nanomaterials with novel morphologies, such as hydroxides, oxides, carbides, sulfides, etc., have been applied to the electrochemical aspects brought to the attention of the people. The transition metal compounds nanomaterials which have adjustable morphology and structure were synthesized by simple hydrothermal method and calcination method, such as Ni(OH)2 nanosheets, CoO nanowires, Mo2C nanowires, et al. All the nanostructured materials were applied to supercapacitor electrode or lithium-ion battery anode, and have made some progress. In this paper, the concrete content that we study includes the following three parts:1. The Ni/Ni(OH)2 hybrid which composed by layered porous Ni(OH)2 nanosheets and NiO nanochains were synthesized via hydrothermal process followed by a hydrothermal process or a calcination treatment. Throughout the experiment, the amount of the reducing agent N2H4·H2O is the key to the morphology of the Ni substrate, thus controlling the morphology of the subsequent Ni/Ni(OH)2 hybrid and NiO nanochains. Then, the structure and morphology of Ni/Ni(OH)2 hybrid and NiO nanochains were characterized by XRD, SEM, FETEM, TEM, BET and FTIR. Synthesized Ni/Ni(OH)2 hybrid and NiO nanochains are applied to supercapacitor electrode, and having excellent electrochemical properties. At a current density of 2 A g-1, the specific capacitance was 3247 F g-1; the specific capacitance of NiO nanochains electrode was 413 F g-1 at a current density of 1 A g-1. This method is simple, efficient and environmentally friendly.2. The Co(C03)0.5(OH)·0.11H2O were synthesized via a hydrothermal process, its morphology could be controlled by adjusting the pH. The Co(CO3)0.5(OH)·0.11H2O precursors with smaller size respectively calcined at a high temperature in tube furnace or muffle furnace, then the CoO nanowires and Co3O4 nanowires were obtained. The CoO nanowires and Co3O4 nanowires were applied to anode materials for lithium-ion batteries, and achieved a certain effect. When the current density was 0.1 C, the CoO nanowires and Co3O4 nanowires exhibit a high specific capacity of 850 mA h g-1 and 1027 mA h g-1 at the first charge-discharge cycle.3. The MoO3-EDA was prepared by simple hydrothermal method, the MoO3-EDA with different morphologies could obtained by adjusting the hydrothermal temperatures. The Mo2C nanowires were obtained by calcinating MoO3-EDA precursor nanowires at a high temperature under a H2-Ar flow (10% H2 by volume) in tube furnace. The different morphologies of MoS2 could be got by the hydrothermal reaction of MoO3-EDA precursor with different morphologies and different sulfur sources. The structure and morphology of Mo2C nanowires and MoS2 nanowires or particles were analyzed by XRD, SEM, TEM, BET and FTIR. After analysis and comparison, the Mo2C nanowires and MoS2 nanowires were respectively used in lithium-ion batteries anodes, which the specific capacity of the first cycle could reach 1037 mA h g-1 and 743 mA h g-1 at a current density of 0.1 C.