鋰電池負極材料添加催化劑及改性劑 對電化學性能之影響

Electrochemical Effect of Catalyst and Modifer Added to Anode Materials as Lithium Ion Battery

林志兆(Chih-Chao Lin)

指導教授 ： 李源弘

共同指導教授 ： 吳玉祥(Yu-Shiang Wu)

國立臺灣大學/工學院/材料科學與工程學研究所/碩士(2011年)

https://doi.org/10.6342/NTU.2011.10241

摘要

由於針狀焦炭擁有高倍率充放電之優異特性，但礙於其為焦炭，電容量較低，因此將針狀焦炭進行披覆、添加催化劑、石墨化熱處理等改質方式，以增進其電化學性質與電容量。本研究以針狀焦炭為原始材料，將瀝青披覆於針狀焦炭表面，並添加硼酸進行石墨化高溫熱處理，來達到其結構與表面改質的目的，以改善鋰離子電池負極材料結構、表面與電化學特性，並提升充放電電容量及降低第一次不可逆性。實驗以石油焦瀝青披覆於針狀焦炭，將硼酸作為催化劑進行熱處理來達到改質的目的。以X光繞射分析（XRD）分析改質後針狀焦炭人造石墨粉體特性，由層間距d(002) 與石墨化度，來顯示針狀焦炭成為人造石墨結構特性的改變；比表面積儀（BET）分析改質後石墨表面孔洞及表面積的變化；雷射粒徑分析顆粒大小的改變；振實密度檢測體積密度的變化。針狀焦炭經由添加瀝青、硼酸及石墨化改質後之針狀焦炭人造石墨，電性測試結果最為優異，擁有第一次放電電容量356 mAh/g，高於未改質之針狀焦炭206 mAh/g，第一次不可逆性由17.9%降低至9.2%，於第十圈放電仍有351 mAh/g，有效改善其放電電容量。

關鍵字

鋰離子電池 ； 負極材料 ； 針狀焦炭 ； 瀝青 ； 硼酸

並列摘要

As the needle coke has excellent characteristic of high rate charge-discharge, however, the coke capacitance is low; therefore, the needle coke is modified by covering, adding catalyst and graphitization heat treatment to enhance its electrochemical property and capacitance. This study used needle coke as original material, covered the needle coke surface with asphalt, and added boric acid for graphitization high-heat treatment to modify its structure and surface, in order to improve the cathode material structure, surface and electrochemical characteristics of lithium ion battery, increase the charge-discharge capacitance, and reduce the first irreversibility. The needle coke was covered with asphaltic pyrobitumen in the experiment, and the boric acid was used as catalyst for heat treatment to attain the goal for modification. The XRD was used to analyze the characteristics of needle coke synthetic graphite powder. The interlayer spacing d (002) and the degree of graphitization indicated the change in the structure property of artificial graphite derived from needle coke. The BET analyzed the variance in the modified graphite surface pores and surface area. The laser particle size analyzed the change in particle size. The tap density detected the variance in volume density. When the needle coke was mixed with asphalt, boric acid, and graphitized and modified needle coke artificial graphite has the best electrical property test result. The first discharge capacitance was 356 mAh/g, which was higher than the 206 mAh/g of unmodified needle coke. The first irreversibility decreased from 17.9% to 9.2%, and there was still 351 mAh/g at the 10th cycle of discharge. The discharge capacitance was improved effectively.

並列關鍵字

lithium ion battery ； cathode material ； needle coke ； asphalt ； boric acid

參考文獻

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