Synthesis And Formation Mechanism Of CuS And PbTe Based Hierarchical Architectures

Chalcogenide compounds nanomaterials possess special lattice structure and behavior. Chalcogenide compounds and solid solution alloy body is one of the earliest and most mature functional material, and have become promising materials in wide application field. The nano chalcogenide can be classified into two categories of IV-VI and II-VI, these materials exhibit peculiar optical, electrical, magnetic, mechanical and catalytic properties, which have been applied in many fields. As there is a pressing requirement for cost-effective, efficient, and environmentally benign energy conversion and storage(ECS) devices that can power energy demanding areas, ranging from portable electronics(e.g., cell phones, camcorders, laptops) to transportation(e.g., electric vehicles, hybrid electricvehicles) or even stationary, chalcogenide compounds nanomaterials become the key to solve these problems. It is hoped that the physical and chemical properties of nanoscale can be further studied, and the structure of which can be controlled to realize the properties of customization. Given the existence of correlations between nanomaterial property and its morphology, uniformly size distributed and shape structured regularly nanocrystals must be synthesized in order to obtain materials with good performance. At the same time, effective control of the morphology is necessary as well, which are all based on the thorough and clear study of the growt h thermokinetics and mechanism of different preparation methods.In this paper, as research object, Cu S-based and Pb Te-based doped nanocrystal aggregations with special microstructure have been synthesized by hydrothermal/solvent thermal method, in which several unpopular materials are selected as dopant. The relationship between the dopant and the driving force of nanocrystal aggregations was explored, which provides a theoretical basis for further investigation of the controllable preparation of nanocryst al aggregations.Cu S-based flower-like aggregations and Ag PbmSb Tem+2 microspheres are successfully synthesized. Experimental parameters, including reaction time, concentration of KOH and hydrazine, the amount of dopant s and volume ratio of acetone to H2 O, play crucial roles in determining the morphologies and composites of the final products. The effects of important experimental parameters on the molecular level are raised, which are focus on chemical reaction and growth of the aggregation process. Then the relevant reaction mechanisms and growth mechanism are summed up.The lithiation/delithiation processes of these ternary and quaternary alloys basically resemble in their constituent elements, exhibiting a multi-step mechanism. The position of each cathodic/anodic wave does not vary upon doping, which indicates the doping of Ag/Sb at the present levels does not have any impact. However, the Ag PbmSb Tem+2 polycrystalline microspheres, as the anode material of the lithium-ion battery, showing excellent electrochemical performance and high cycle stability.This study is not only confined to Pb Te-based and Cu S-base material via liquid phase synthesis, but also provides certain reference and guidance for controllable synthesis of other chalcogenide nanocrystal doped system.