| 摘要: | 現今電動運輸工具與輕型電子產品蓬勃發展的因素，使得鋰離子二次電池的研究備受重視。隔離膜是鋰電池材料中重要的元件，其主要功能是使用時在正負極之間使鋰離子電解質充分通過，同時能在充放電時對電解液保持高度浸潤性。其性質的優劣決定了電池應用上的性能，隔離膜而環保性的需求一直的提高。因此在安全的設計下，同時帶動了隔離膜在新型材料上的研究發展。
本研究是以靜電紡絲技術，使用部分醋酸纖維素為材料，經過溶液配製、參數調整、靜電紡絲等步驟，選出最佳濃度後，使用兩種噴絲距離(10cm、15cm)、各紡出三種不同工作電壓(10kV、15kV、20kV)的樣品，選取電紡交織優良的纖維之平面薄膜，以探討其微結構之研究。精研醋酸纖維隔離膜的奈米結構，包含奈米級多種孔洞(部分醋酸纖維的孔壁及其交錯形成的奈米級孔洞)結構、電解液浸潤性、熱重損失。檢測醋酸纖維隔離膜與塑料聚乙烯隔離膜之優劣。
經由實驗研究發現，在濃度20%中，噴絲距離10cm、工作電壓15kV時具有電紡纖維特有優良的的交織孔洞、優異的電解液潤濕性、及纖維的平整性等提高了隔離膜的性能。被認為是有機會可取代市面上聚乙烯隔離膜複合平面材料。
Products that use lithium-ion secondary batteries, such as lightweight electronics and electric transportation, are becoming increasingly popular. Isolation membranes are a key element in the manufacturing of lithium batteries. They act as a conductor to fully transport lithium-ion electrolytes between positive and negative electrodes while maintaining the wettability of electrolytes during battery recharge and discharge. The quality of the isolation membranes determines the application performance of the battery. At the same time, the demand for environmental friendliness of such membranes has steadily increased. Therefore, during the design phase, in addition to safety considerations, research and development for new isolation membrane materials are also spurred.
In the present study, an electrospinning instrument was employed to spin cellulose diacetate following such processes as solution formulation, parameter adjustment, and electrospinning. Once the optimal concentration was determined, samples were produced with two different spinning distances (10cm and 15cm) and three different operating voltages (10kV, 15kV, and 20kV). The membrane with the optimal electrospinning properties was then analyzed for its microstructures. The nanoscale properties of the refined cellulose acetate isolation membrane include nanoscale porosity (porous walls of the cellulose acetate and staggered nanoscale pores) structures, electrolyte wettability, and loss of thermal weight. Cellulose acetate isolation membranes were then compared with plastic polyethylene isolation membranes.
The test results revealed that favorable staggered pores, electrolyte wettability, and fiber smoothness were achieved with a concentration of 20%, a spin distance of 10cm, and an operating voltage of 15kV, which enhanced the membrane performance. Thus, cellulose acetate could substitute for the composite materials used for polyethylene isolation membranes that are currently available on the market. |
