Research
Leave-Intercalation Theory and Conductive Mechanism during Charge-Discharge Process for Secondary Battery
The source of conductive ions in the charge and discharge process of AB5/ β -Ni(OH)2, 2H-graphite/ LiMeO2 and 2H-graphite/LiFePO4 batteries is thought to be provided by the phase transition of positive active materials, so it is called phase transition theory. Through the detailed study of the charge and discharge processes of AB5/ β -Ni(OH)2, 2Hgraphite/ Li(Ni1/3Co1/3 Mn1/3)O2 and 2H-graphite/LiFePO4, it is found that the source of conductive ions is the de-intercalation of H (nickel-hydrogen battery) and Li (lithium-ion battery) in positive and negative active materials, and the de-intercalation theory is proposed. On this basis, the conductive mechanisms of these three types of batteries are clarified: The directional migration and movement of conductive ions under the action of electric field.
Study on the Mechanism of Cycle and Storage Process of Lithium-ion Battery
The changes of battery performance, crystal structure, fine structure and microstructure of positive and negative active materials in the processes of cycle and storage of lithium-ion battery were studied experimentally, and the change of battery performance was related to the structure change of positive and negative active materials. The mechanism of cycle and storage process was revealed, and the attenuation mechanism of battery cycle performance and storage performance was discussed. The method and action mechanism of improving cycle-storage performance are introduced.
Test and Research of Silicon Materials in Integrated device Engineering
It is of great practical significance to test and analyze the quality of silicon materials used in integrated devices and their changes in planar thermal process. This paper summarizes the international test, analysis and research results. The contents include polycrystal preparation, single crystal growth and its crystal defects, wafer cutting, grinding and polishing, wafer tracking observation and analysis in plane thermal process, generation control and elimination of induced dislocations, etc.
The Characters and Mechanism Research of Hydrogen Absorption/Desorption Kinetics for Alloy Hydrogen Storage Materials
The characters of hydrogen absorption/ desorption kinetics for alloy hydrogen storage materials have been summarized. For searching the nature of hydrogen absorption/desorption kinetics, the experimental research results of evolution of the phase structure during hydrogen absorption/desorption processes have been summarized. It is found that hydrogen storage host is hydride for Mg system alloys and is hydrogenation solid solution for Ti and rare-earth systems. The situation of atom close packing and the number of interstitial sites as well as size of interstitial space of hydrogen storage materials were compared. The crystallographic behaviors in hydrogen absorption/ desorption processes have been expounded. The characters of hydrogen storage kinetics for alloy hydrogen storage materials were qualitatively explained from the thermodynamics of crystallographic behaviors. Under appropriate hydrogen pressure and different temperature, characters of hydrogen absorption kinetics curves are: (1) The hydrogen absorption rate of initial stage and saturation quantity of hydrogen absorption increase with temperature increase for the materials (Mg system) that the host of hydrogen absorption is the hydride; (2) The hydrogen absorption rate of initial stage and saturation quantity of hydrogen absorption decrease with temperature increase for the materials (Ti and rare-earth systems) that the host of hydrogen absorption is the hydrogenation solid solution.
