本論文之研究主旨為探討電解液中加入複合式添加劑，對於鋅空氣電池的自放電腐蝕析氫與充電時生成樹枝狀結構等現象之抑制，並測試不同複合式添加劑對於鋅空氣電池循環充放電效能影響。電池使用發泡鎳為基材，經錫表面改質與預鍍鋅兩步驟，製作穩定性陽極；基礎電解液為含醋酸鋅之鹼性溶液（8M KOH + 0.45M Zn(CH3COO)2）；電解液添加劑選擇乙二胺四乙酸（EDTA）、酒石酸（Tartaric acid）、3-乙基-3-戊醇（3-Ethyl-3-pentanol）、聚山梨醇酯二十（Tween 20）與氯化亞錫（SnCl2）等單獨加入電解液中，首先以循環伏安法（Cyclic voltammetry, CV）找尋單一添加劑的最佳參數，再由線性極化法（Tafel polarization）、電化學阻抗頻譜法（Electrochemical impedance spectroscopy , EIS）與掃描式電子顯微鏡（Scanning electron spectroscopy, SEM）觀察鋅極表面形貌，來驗證各種單一添加劑的優劣。根據實驗結果，選出EDTA、3-Ethyl-3-pentanol與SnCl2三種添加劑來互相混和，做為複合添加劑選用的參考。循環伏安法、電化學阻抗頻譜法分析以及鋅電極之SEM形貌觀察等結果顯示複合添加較單一添加劑在抑制析氫反應有較好效果，尤以3.4mM EDTA+5.2mM SnCl2與12.9mM 3-Ethyl-3-pentanol+5.2mM SnCl2兩種複合添加劑之效能最佳。於是，最後選擇此兩種複合添加劑運用製作全電池，進行全電池充放電量測，經多次充放電循環測試後，比較電池穩定性與電池電容量變化，結果顯示3.4mM EDTA+5.2mM SnCl2的極化電阻較高（Rp=1613.7 Ω/cm2），循環壽命較高（250 cycles），電容量較高（仍有244.5 mAh/g），電容量保留率較佳（仍保有81.5%效果）。;In the present work, an attempt was made to enhance the cyclic life of charging-recharging and retention rate of electric capacity for a zinc-air battery by modifying its electrolyte in terms of additives. Organic (such as EDTA; tartaric acid; 3-Ethyl-3-pentanol; Tween 20) and inorganic (like SnCl2) compounds were singly or combined used as the additives to study the inhibition of the Zn-dendritic formation resultant from charging process and zinc-corrosion owing to self-discharge of the cell. Electrochemical tools included cyclic voltammetry, linear and Tafel polarization and electrochemical impedance spectroscopy (EIS) with an aid of morphological observation through a scanning electron microscopy (SEM) were used to evaluate the efficiency of the additives. Resulting from CV analysis, we found that combined use of the additives is better than single use. The role of 3.4mM EDTA leads to hinder the hydrogen evolution; the role of 12.9mM 3-ethyl-3-pentnaol results in a reduction of Zn-dendritic growth; and addition of 5.2mM SnCl2 improves the bath conductivity of the cell. In the system involving combined additives, we found that a combination between 3.4mM EDTA+5.2mM SnCl2 and that between 12.9mM 3-Ethyl-3-pentanol+5.2mM SnCl2 reveal better inhibition in hydrogen evolution than their single use. Both types of combined additives were utilized to assemble a complete Zn-air single cell for charging-discharging test. After 250 times of cyclic test, the cell modified by 3.4mM EDTA+5.2mM SnCl2 reveals the best energetic capacity (remaining 244.5 mAh/g) with the highest retention rate in capacity (roughly at 81.5%).
