常壓噴射電漿處理還原氧化石墨烯與鋰錳氧化物電極於柔性非對稱超級電容器中的應用

Abstract

本研究提出一種應用於柔性非對稱超級電容（Asymmetric Supercapacitor, ASC）之製程方法，利用常壓噴射電漿（Atmospheric-Pressure Plasma Jet, APPJ）對還原氧化石墨烯（rGO）與鋰錳氧化物（LMO）電極進行表面改質，以調控其微觀結構並提升電化學性能。電極材料分別由rGO-LiCl-Mn(NO3)2⋅4H2O複合漿料及純rGO漿料製備，透過網版印刷轉印至碳布基材後進行APPJ處理，最後與聚乙烯醇–硫酸鋰（PVA–Li₂SO₄）凝膠電解質組裝為三明治結構的柔性非對稱超級電容。 材料分析結果顯示，APPJ處理顯著改變電極表面微觀結構與化學組成。SEM影像觀察到表面形成多孔性奈米結構，提升了比表面積與電解質滲透性；接觸角量測結果顯示，電漿處理後的電極具備良好親水性，有助於提升與電解質的接觸效率。XRD與XPS分析則確認電極表面生成LiMnO₂與LiMn₂O₄等具高理論電容的晶相，且表面含氧官能基與高價態錳比例上升，增強了法拉第反應活性與電荷儲存能力。 電化學測試結果顯示，經APPJ處理300秒之裝置（ASC-300s）在1.6 V操作電壓下，可達最大面積比電容40.47 mF/cm²與能量密度9.40 μWh/cm²。該裝置亦展現優異的循環穩定性，於4000次充放電後仍維持96%電容，並在彎曲曲率1 cm⁻¹下保有89%電容，展現出良好的機械穩定性。Ragone plot進一步顯示其具備優異的能量與功率密度平衡特性。 綜上所述，本研究成功運用APPJ技術進行柔性電極之表面改質，有效提升其界面特性與儲能表現，並成功製備具高性能、長壽命與良好可撓性的非對稱超級電容。此成果不僅拓展了常壓電漿於儲能材料領域的應用，也為穿戴式電子與便攜式能源系統提供具發展潛力的儲能解決方案。

This study presents a flexible asymmetric supercapacitor (ASC) fabricated through atmospheric-pressure plasma jet (APPJ) treatment to enhance the electrochemical performance of reduced graphene oxide (rGO) and lithium manganese oxide (LMO) electrodes. The electrode films were prepared by screen-printing a rGO–LiCl–Mn(NO₃)₂·4H₂O composite and pure rGO slurry onto carbon cloth substrates, followed by APPJ surface modification. The resulting electrodes were assembled into a sandwich-structured device using a PVA–Li₂SO₄ gel electrolyte. Material characterization confirmed that APPJ treatment effectively tailored the electrode surface. SEM revealed porous nanostructures, contact angle measurements showed improved wettability, and XRD/XPS analyses identified the formation of LiMnO₂ and LiMn₂O₄ phases, along with increased oxygen functional groups and high-valence Mn—both of which contribute to enhanced faradaic activity and charge storage capability. The optimized device (ASC-300s) achieved an areal capacitance of 40.47 mF/cm² and energy density of 9.40 μWh/cm² at 1.6 V, with 96% retention over 4000 cycles and 89% retention under 1 cm bending radius. Ragone plot analysis further confirmed its balanced energy and power density. Overall, APPJ provides a simple yet effective approach to enhance the interfacial and electrochemical properties of flexible electrodes, enabling the development of high-performance, durable, and mechanically resilient ASCs for wearable and portable energy storage applications.