| 摘要: | 太陽能產業的迅速成長下，廣設的太陽能模組壽命終止時所產生的大量廢棄物會對環境造成極大的傷害，使得太陽能模組相關的回收研究成為一個重要的議題。太陽能模組中有許多部件得以回收，而現行的回收方法多以純化提煉有價元素為主，此種方法雖可以有效回收廢棄物，但往往需要高溫熱處理及使用腐蝕液體，若沒有妥善處理將會對環境造成二次傷害，因此研發一種對環境友善的回收方式是必須的。目前市場上以矽太陽能模組為最主要的技術，而矽同時也被視為是一種非常有潛力的鋰離子電池負極材料，因此本研究著重於再利用廢棄太陽能模組中的太陽能電池，有別於以往純化提煉的回收方法，此處提出一個簡單的製程直接再製廢棄太陽能電池。本研究透過濕式球磨法製備Si/SiOx/Al2O3複合材料，並與碳紙基材製成複合式負極應用於鋰離子電池中。此實驗探討不同研磨時間及轉速下對Si/SiOx/Al2O3造成的影響，並定義出最佳參數。根據結果顯示隨著研磨時間或轉速的提升，Si/SiOx/Al2O3粉體的團聚現象及氧化程度將會增加，且該複合式電極在500 rpm轉速下研磨2個小時呈現最佳的電化學性能，即使在2000 mA/g的速率下仍保持866 mAh/g的放電容量，而在200 mA/g速率下第100次循環後也仍擁有1423 mAh/g的放電容量和74.5%的容量保持率。
此外，本實驗還更進一步研究表面改質後的碳紙基材對於整體複合式負極的電化學性能影響，從結果顯示含有氮官能基的碳紙有助於更加提升整體的電化學表現。跟未改質的碳紙相比，在200 mA/g的速率下進行循環壽命測試，其在100次循環後放電容量和容量保持率分別提高至1603 mAh/g和90.6%，顯示氮的摻雜有助於提升複合式負極在循環中的電化學穩定性和放電電容量。本實驗表明廢棄太陽能電池可以透過簡單且環保的製程再製成Si/SiOx/Al2O3複合材料，並結合碳纖維基材形成高效能的鋰電池負極。
;With the rapid growth of the solar energy industry, the large amount of end-of-life solar modules will cause negative environmental impacts. Recycling of end-of-life solar modules will become a critical issue for next decade. Many components in solar modules can be recycled, and the current recycling methods mostly focus on purification and extraction of valuable elements. Although this method can effectively recycle waste, it often requires high-temperature heat treatment and corrosive liquids. It may cause secondary pollution to the environment, so it is necessary to develop an environmentally friendly recycling method. At present, the solar modules on the market are dominated by silicon, and silicon is regarded as a promising anode material for lithium-ion battery. Therefore, this research focuses on reusing solar cells of waste solar modules, which is different from the previous purification. Based on this concept, we select the wet ball milling method to prepare Si/SiOx/Al2O3 composite material, and further form a composite anode with a carbon paper substrate for lithium-ion battery. This experiment explores the influence of different ball milling time and different rotation speed on Si/SiOx/Al2O3, and the best parameters are defined. According to the results, the agglomeration is more serious and the oxidation degree is increased with increasing ball milling time or rotation speed. The composite electrode treated at 500 rpm for 2 hours exhibits discharge capacity of 1423 mAh/g with 74.5% capacity retention after 100 cycles at 200 mA/g. Even at 2000 mA/g, it still deliver discharge capacity of 866 mAh/g.
In addition, this work further study the influence of the modified carbon paper substrate on the electrochemical performance of composite anode. The analysis results show that the carbon paper containing nitrogen functional groups can further improve the electrochemical performance. After 100 cycles, the discharge capacity and capacity retention rate are increased to 1603 mAh/g and 90.6%, respectively. It indicates the nitrogen doping can increase the electrochemical stability and discharge capacity of the composite anode during cycling. Overall, this study demonstrates that waste solar cells can be transformed to Si/SiOx/Al2O3 composite materials directly through a simple and environmentally-friendly process. In addition, CF-based Si/SiOx/Al2O3 composite exhibits favorable performance in terms of cycling stability and rate capability. |
