Surface Modification on Lithium Iron Phosphate Cathode Materials for Improving Electrochemical Performance Using Microwave-assisted Method

• Main Authors: Chuan-Ju Liu, 劉娟如
• Other Authors: C.-T shies
• Format: Others
• Language: zh-TW
• Online Access: http://ndltd.ncl.edu.tw/handle/94796654585852097279

碩士 === 元智大學 === 化學工程與材料科學學系 === 102 === his thesis proposed an efficient microwave-assisted approach to prepare metal-coated lithium iron phosphate (LFP) cathode materials for improving electrochemical performance of Li-ion batteries. Two kinds of metallic ions, Cu and Zn, were employed as conductive layer over the surface of LFP powders through the microwave deposition method. The as-prepared LFP powders still kept their original morphology after the metallic coatings. Based on the micro-structural observation, the presence of metallic layers induces not only a decrease of interfacial resistance but also a remarkable increase of rate capability. Experimental results indicated that the Cu-coated LFP cathode displayed the maximal cell performance, i.e., the specific capacity of 146 mAh g-1 at 0.1 C and the enhanced cyclic stability of 6% capacity fading after 50 cycles. This enhanced performance could be attributed to the fact that the Cu thin layer enables the repairing of incomplete original carbon network, showing a completed electronic circuit onto the LFP powders. The Cu-coated LFP, thus, leads to faster kinetics of electrons and better reversibility of Li ions in the olivine crystals. Accordingly, the microwave-assisted approach offers a great potential in modifying cathode materials due to its short synthesis time, low-temperature operation, and energy-saving.