LiMn2O4 /聚亞醯胺混成膜之製備及其特性研究

Abstract

本論文合成的兩系列LiMn2O4/PI混成膜，分別由ODA/ODPA及p-BAPB/ODPA形成聚醯胺酸溶液後，添加不同比例的乙醯丙酮鋰錳混合物於其中，形成的乙醯丙酮金屬/聚醯胺酸混合溶液再配合XRD圖譜，找出適當的製程溫度，在成膜性及LiMn2O4相生成的雙重考量下，以階段式升溫：100℃(1hr)、200℃(1hr)、250℃(1hr )、300℃( 6hr 和10hr) 兩製程條件，成功的將LiMn2O4在低溫下燒結於聚亞醯胺中，形成LiMn2O4/PI混成膜。 在兩系列混成膜樣品的IR圖譜均顯示，Mn-O吸收峰(615、515 cm-1)的強度，均會隨著製程溫度及時間、和添加的乙醯丙酮金屬比例增加而增強，表示LiMn2O4結晶隨之增高。TGA分析均顯示，隨乙醯丙酮金屬莫耳比增加、製程時間增長，Td下降的趨勢增加，推測其原因為金屬氧化物催化熱氧化裂解反應，造成熱安定度下降。電性質方面，兩系列混成膜樣品的導電率均隨加入乙醯丙酮金屬混合物的莫耳比增加而提高，約為10-12~10-11 Ω-1 cm-1，較純PI提升了10~1000倍。在表面型態方面，兩系列混成膜樣品的橫截面(cross section)SEM圖顯示，在LiMn2O4 /聚亞醯胺混成膜中鋰錳氧化物的粒徑大小隨著莫耳比增加而增大，但相較一般固態合成法樣品的粒徑已減小許多。

Two series of metal containing poly(amic acid)s, precusors of LiMn2O4 / Polyimide hybrid films, were derived from pure PAAs and Li and Mn acetylacetone. The pure PAAs were prepared with ODPA (4,4- oxydiphthalic anhydride) and ODA (4,4'-diaminodiphenylether), or ODPA and p-BAPB (1,3-bis(4-aminophenoxy)benzene). The metal-containing PAAs were converted to LiMn2O4 / Polyimide hybrid films by step thermal imidization: at 100℃, 200℃,and 250℃each for 1hr, and 300℃ for 6hr or 10hr . In these conditions, LiMn2O4 could successfully be sintered in polyimides at low temperatures in one process. The LiMn2O4 / Polyimide hybrid films were characterized with the X-ray diffraction spectrum (XRD). In the two series of the hybrid films, IR figures showed the intensities of Mn-O vibration bands(615, 515 cm-1) enhanced with increasing process temperature, process time, and Li and Mn acetylacetone contents. It represented the hybrid films having more crystalline LiMn2O4 phase under these conditions. TGA profiles showed Tds decreased with increasing process time and metal acetylacetone contents. The results might be related to the metal oxide catalyzing the oxidative degradation reaction and decreasing the thermal stability of hybrid films. Conductivities of the hybrid films could be up to ~10-11 Ω-1 cm-1, which were 1~3 orders higher than that of pure polyimide. SEM pictures of the hybrid films cross sections showed the metal oxide sizes increase with increasing metal acetylacetone contents, but they were smaller than that with the solid state method.