Using rotating ring disk electrode to study the electrochemical performance of Mn3O4 particle in rechargeable Li-O2 batteries

• Main Authors: Hong-kai Yang, 楊宏凱
• Other Authors: Jenn-Shing Chen
• Format: Others
• Language: zh-TW
• Published: 2014
• Online Access: http://ndltd.ncl.edu.tw/handle/46407212683052596229

碩士 === 國立高雄大學 === 應用化學系碩士班 === 103 === In recent years, Li-O2 batteries are much attractive because of the huge theoretical energy density close to fossil fuels. The disadvantage of Li-O2 battery is high overpotential between charge and discharge. That will cause the decomposition of the electrolyte, and poor efficiency of the cycle life. The application of catalysts can effectively decrease the Li−O2 recharge potential. In this study, we use the surfactant and manganese sulfate as a precursor solution, and to preparing Mn3O4 particles by using ultrasonic atomization as a catalyst using in the Li-O2 battery cathode. The physical characteristics and electrochemical performance of the Mn3O4 particles was investigated using X-ray diffraction, scanning electron microscopy particle size analysis, BET measurements, charge-discharge tests and rotating ring disk electrode experiments (RRDE). Rotating ring disk electrode experiments can be divided into two parts. The first part is using the electrolyte without lithium ion. We could find the material oxygen reduction rate constant(kf) by Levich-koutechy equation and decomposition of the electrolyte reaction rate constant(k) by collection efficiency. The second part is using the electrolyte solution containing lithium ions. Make the reaction system close to the Li-O2 battery system. And using RDE experiments to fide the polarization curves and compare with aircell test. Form the test, employing the Mn3O4 as electrocatalyst in Li-air batteries, the Li-air batteries display lower overpotential and good discharge capacity. This result demonstrates Mn3O4 are promising cathode electrocatalysts for non-aqueous Li-air batteries.