探討靜電紡絲法之氣體擴散層與二氧化碳吸附膜在鋅空氣電池之應用

Fabrication of Electrospinning Nanofibers and Preparation of CO2 Adsorption Membrane for Zinc-air Battery Application

朱耀廷(YAO-TING JU)

指導教授 ： 李元堯

國立中正大學/工學院/化學工程學系/碩士(2016年)

摘要

本研究第一部分為利用靜電紡絲法分別製備PVDF奈米纖維與含奈米碳球的碳纖維，並將其製成靜電紡絲氣體擴散層（Gas diffusion layer，GDL），然後與奈米碳球粉末氣體擴散層（CNC GDL）及商用防水透氣膜（PTFE membrane）進行材料特性與鋅空氣電池效能之比較，研究中鑑定氣體擴散層的結構型態、親疏水性、孔徑大小、孔徑分布、孔隙率與透氣性，從結果得知，靜電紡絲奈米纖維呈現不織布纖維結構且具有三維孔隙，使其相較於其他種類的氣體擴散層有較佳的透氣率；經由全電池測試後，各種氣體擴散層所能達到的最大功率密度大致相近，但於高電流密度下（150 - 200 mA/cm2），靜電紡絲氣體擴散層有較佳的電池效能，其原因為此材料具有高透氣率。
二氧化碳會與鹼性電解液（KOH）反應生成碳酸鹽，進而對鋅空氣電池造成影響。因此本研究第二部分先探討二氧化碳對電池之影響，經循環充放電12小時後，若進氣使用較高的二氧化碳濃度（10000 ppm），可觀察其空氣電極出現一些直徑為4 – 12 μm的碳酸鹽粒狀物質。為了解決二氧化碳對鋅空氣電池之影響，本研究利用簡易之含浸法將分枝聚乙烯亞胺（PEI）嵌入活性碳纖維氈（ACF felt）中，製備出不同PEI含量之二氧化碳吸附膜，從結果中得知，含有80 wt% PEI的活性碳纖維氈有較佳的吸附能力，於進氣流速30 ml/min與測試氣體含400 ppm二氧化碳的測試條件下，其吸附量為1.51 mmolCO2/gadsorbent，另外，以進氣流速20 ml/min的測試條件下，於測試時間12.5小時內皆無二氧化碳通過吸附膜。最後將吸附膜安裝於電池上，經循環充放電12小時後，可發現其降低碳酸鹽的生成。

關鍵字

鋅空氣電池 ； 氣體擴散層 ； 二氧化碳吸附 ； 靜電紡絲

並列摘要

The study in this thesis is divided into two parts. The first part of the study is the investigation of performance of the gas diffusion layer (GDL) using electrospun polyvinylidene fluoride (PVDF) nanofibers (NFs) felt and carbon nanocapsule polyacrylonitrile-based carbon nanofibers (CNC PAN-based CNFs) felt. The characterizations of as-prepared nanofibers GDL were compared with carbon nanocapsule GDL (CNC GDL) and commercial PTFE membrane. Critical properties of the above mentioned materials including surface morphologies, pore size, gas permeability, porosity and water contact angle, have been studied for the effect of the GDLs. Finally, four types of GDL were used in Zn-air battery for the comparison. The electrospun nanofibers were in the form of nonwoven fabric structure with three-dimensional pores. Therefore, it showed higher gas permeability than the CNC GDL and the PTFE membrane. The results of the full cell test also shows a better performance using electrospun GDL than other GDL in the high current density region (150-200 mA/cm2). Because of its relatively high gas permeability.
Formation of carbonate on air electrode was investigated as a function of the CO2 concentration in the feed gas. By increasing the CO2 concentration in synthetic gas up to 10000 ppm, the carbonate particles were formed with diameters between 4 and 12 μm on air electrode after the battery was operated for 12 hrs. The second part of the study is the formation of the CO2 adsorber for the use in Zn-air battery. Polyethylenimine (PEI) were impregnated into an activated carbon fibers felt (ACF felt). The 80 wt% PEI loaded ACF felt achieved the largest capacity of 1.51 mmolCO2/gadsorbent under a 30 ml/min flow rate and CO2 feed concentration of 400 ppm. CO2 concentration was remained at 0 ppm under a gas flow rate of 20 ml/min for 12.5 hrs. The CO2 adsorption membrane was used on Zn-air battery. The result showed that formation of carbonate was reduced on air electrode after an operation of 12 hrs.

並列關鍵字

Zinc/air battery ； Gas diffusion layer ； carbon dioxide adsorption ； Electrospinning

參考文獻

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