利用常壓電漿改質正極極片以提升鋰離子電池效能之研究

Abstract

各國政府為了節能減碳、降低環境污染、帶動綠能產業發展等目標下，積極推動電動機車與智慧電動車，而動力鋰電池是主要的關鍵零組件。動力鋰電池除了可提供智慧電動車需求、加速綠能產業發展，也可應用於再生能源儲電系統。本論文乃研究鋰離子二次電池(lithium-ion secondary battery)之正極極片經常壓電漿改質後對鋰離子電池之影響，期望藉由親水官能基接枝於富鋰正極材料LNMO (Li1.2Mn0.6Ni0.2O2)表面, 而形成非晶質相含碳化合物來達成提升富鋰材料之保護，避免Ni、Mn離子自結構中釋出以改善電容量衰退的現象。 研究中針對富鋰正極材料LNMO進行常壓電漿改質，在固定的工作氣體流量、射頻電漿瓦數、極片與噴頭間距、基座移動速率下改變掃描次數以探討其對正極極片表面與鋰離子電池之電池性能的影響。 根據實驗結果可歸納出 (1)由TEM分析結果所示，經常壓射頻電漿改質過後的LNMO正極材料表面並沒有因為親水官能基接枝而形成如非晶質相之化合物，反而發現材料表面粗糙度上升，推測是電漿改質過程中電漿內離子轟擊所造成之結果，以致材料表面積提升，或許有助於電化學氧化還原反應的發生；(2)經常壓射頻電漿改質過後之LNMO正極所製成之陰極半電池擁有比未改質過LNMO正極所製電池較高的電容量；(3)經循環充放電測試後，經常壓射頻電漿改質過後之LNMO正極所製成之陰極半電池仍然擁有比未經改質過LNMO正極所製電池較高的電容量。

Vehicles are a major pollution contributor, producing significant amounts of nitrogen oxides, carbon monoxide, and other pollution. In order to reduce those pollution mentioned above, many countries start to develop new technology---Lithium ion battery, the crucial component that applies to many industries, without a doubt, is as at their first priority. Lithium ion battery not only provides the stable energy but also gives electronic power to be recycled and reused. This research is demonstrates the cathode material : LNMO (Li1.2Mn0.6Ni0.2O2) is treated by Atmospheric Pressure Plasma Jet (APPJ) --- under the same flow of air, RF power, the same distance between electrode and jet, and the same frequency of moving stage, to examine the relationships/differences between the surface of cathode electrode and the functionality of lithium battery. In the thesis, we suppose that the APPJ surface modification reaction can cause various defects on LNMO surface. The effect of plasma-induce ion bombardment contributes such defects, of which is beneficial for enhancement of battery capacity from series electrochemical characterizations.