کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
4766941 1424109 2017 32 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Effect of cathode porosity on the Lithium-air cell oxygen reduction reaction - A rotating ring-disk electrode investigation
ترجمه فارسی عنوان
اثر تخلخل کاتدی بر واکنش کاهش اکسیژن سلولی لیتیوم-هوا - بررسی الکترود چرخ دنده
کلمات کلیدی
واکنش کاهش اکسیژن، سلول اکسیژن لیتیم، سینتیک الکتروشیمیایی، الکترود کربن، الکترود روی دیسک چرخش
موضوعات مرتبط
مهندسی و علوم پایه مهندسی شیمی مهندسی شیمی (عمومی)
چکیده انگلیسی
The kinetics of the oxygen reduction reaction (ORR) on the practical air cathode in a Lithium-air cell, which is conventionally composed of porous carbon with or without catalysts supported on it, was investigated. The mechanism and kinetics of the oxygen reduction reaction (ORR) was studied on a porous carbon electrode in an oxygen saturated solution of 0.1 M Lithium bis-trifluoromethanesulfonimide (LiTFSI) in Dimethoxyethane (DME) using cyclic voltammetery (CV) and the rotating ring-disk electrode (RRDE) technique. The oxygen reduction and evolution reactions were found to occur at similar potentials to those observed on a smooth, planar glassy carbon (GC) electrode. The effect of porosity and the resultant increase in surface area were readily observed in the increase in the transient time required for the intermediates to reach the ring and the much larger disk currents (compared to smooth, planar GC) recorded respectively. The RRDE data was analyzed using a kinetic model previously developed by us and the rate constants for the elementary reactions were calculated. The rates constant for the electrochemical reactions were found to be similar in magnitude to the rate constants calculated for smooth GC disks. The porosity of the electrode was found to decrease the rate of desorption of the intermediate and the product and delay their diffusion by shifting it from a Fickian regime in the electrolyte bulk to the Knudsen regime in the film pores. Thus, it is shown that the effect of the electrode porosity on the kinetics of the ORR is physical rather than electrochemical.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Electrochimica Acta - Volume 248, 10 September 2017, Pages 570-577
نویسندگان
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