Suppressing the Coffee-Ring Effect in Semitransparent MnO2 Film for a High-Performance Solar-Powered Energy Storage Window

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• 作者：Huanyu Jin ; Jiasheng Qian ; Limin Zhou ; Jikang Yuan ; Haitao Huang ; Yu Wang ; Wing Man Tang ; Helen Lai Wa Chan
• 刊名：ACS Applied Materials & Interfaces
• 出版年：2016
• 出版时间：April 13, 2016
• 年：2016
• 卷：8
• 期：14
• 页码：9088-9096
• 全文大小：636K
• 年卷期：0
• ISSN：1944-8252

文摘

We introduce a simple and effective method to deposit a highly uniform and semitransparent MnO₂ film without coffee-ring effect (CRE) by adding ethanol into MnO₂ ink for transparent capacitive energy storage devices. By carefully controlling the amount of ethanol added in the MnO₂ droplet, we could significantly reduce the CRE and thus improve the film uniformity. The electrochemical properties of supercapacitor (SC) devices using semitransparent MnO₂ film electrodes with or without CRE were measured and compared. The SC device without CRE shows a superior capacitance, high rate capability, and lower contact resistance. The CRE-free device could achieve a considerable volumetric capacitance of 112.2 F cm^–3, resulting in a high volumetric energy density and power density of 10 mWh cm^–3 and 8.6 W cm^–3, respectively. For practical consideration, both flexible SC and large-area rigid SC devices were fabricated to demonstrate their potential for flexible transparent electronic application and capacitive energy-storage window application. Moreover, a solar-powered energy storage window which consists of a commercial solar cell and our studied semitransparent MnO₂-film-based SCs was assembled. These SCs could be charged by the solar cell and light up a light emitting diode (LED), demonstrating their potential for self-powered systems and energy-efficient buildings.