studies on electrode kinetics of liithiium anode of lithium secondary batteries

• Main Authors: chen, maw-jen, 陳茂珍
• Other Authors: chang yu-chu
• Format: Others
• Language: zh-TW
• Published: 1997
• Online Access: http://ndltd.ncl.edu.tw/handle/86633444553844563897

碩士 === 淡江大學 === 化學工程學系 === 85 === Interest in nonaqueous high energy batteries ( Lithium battery ) is reflected in an increasing number of investigations concerning the electrochemical bebavior of active metals in nonaqueous solvents. The electrochemical methods (cyclic voltammery and stable polarity) to study that electrochemical oxidation process on Ni electrodes in electrolytes and kinetic parameters of the deposition-dissolution process with Lithium anode. Interruption of the current is used frequently to assess the magnitude of the ohm potential drop that is included in the measurement of electrode potentials during the passage of current. The value so measured corresponds to the primary current distribution in the electrode system being studied. The measurement of ohm drop for the salts (LiClO4, LiBF4, and LiPF6) is closed. Kinetic data (exchange current density and Tafel slope) were deduced from the experimental results. The exchange current density was follows: LiClO4 (low potential range)< LiPF6 ,LiBF4< LiClO4 (high potential range). The exchange current density with the microelectrodes were higher than big electrodes, so the measurement of the kinetic data that the mass transport is important. All of the electrolytes system, the slope of a linear relationship between the square root of the exchange current and the square root of the concentration is about 0.8. We use cyclic voltammograms at various sweep rates for Ni electrodes in electrolytes. At the first anodic scan, the anodic current started at 4.0V(vs. Li/Li+) for LiClO4, 3.5V for LiBF4 and LPF6.the peak current was observed that LiClO4 is higher, LiPF6 and LiBF4 is smaller, but don't see DEC/ LiBF4.it can higher 1V for EC/DEC. A linear relationship between the peak current and the sweep rate or the square root or the sweep rate, but back is better than forward, and they didn't through the zero point. The electrochemical process taking place on the Ni electrode during the anodic polarization was not a simple diffusion-limiting process but may have resulted from several different reactions occurring simultaneously.