Ionic Liquid-Derived Imidazolium Cation Linkers for the Layer-by-Layer Assembly of Polyoxometalate-MWCNT Composite Electrodes with High Power Capability

详细信息    查看全文

• 作者：Matthew Genovese ; Keryn Lian
• 刊名：ACS Applied Materials & Interfaces
• 出版年：2016
• 出版时间：July 27, 2016
• 年：2016
• 卷：8
• 期：29
• 页码：19100-19109
• 全文大小：632K
• 年卷期：0
• ISSN：1944-8252

文摘

Imidazolium cations derived from ionic liquids were demonstrated as effective linker molecules for the layer-by-layer (LbL) deposition of polyoxometalates (POMs) to increase the charge storage of multi-walled carbon nanotube (MWCNT) electrodes. MWCNTs modified with GeMo₁₂O₄₀^4– (GeMo₁₂) via an imidazolium cation linker demonstrated highly reversible redox reactions and a capacitance of 84 F cm^–3, close to 4 times larger than bare CNT. Compared to CNT-GeMo₁₂ composites fabricated with a conventional polyelectrolyte linker poly(diallyldimethylammonium chloride), (PDDA), the imidazolium cations resulted in lower POM loading, but higher conductivity and in turn superior performance at fast charge–discharge conditions. A polymerized imidazolium linker (PIL) was also synthesized based on the ethyl–vinyl–imidazolium monomer. CNT-GeMo₁₂ composites fabricated with this PIL achieved high POM loading comparable to PDDA, while still maintaining the good conductivity and high rate capabilities shown by the monomer imidazolium units. The high conductivity imparted by the PIL is especially valuable for the fabrication of multilayer POM composites. Dual-layer GeMo₁₂ O₄₀^4––SiMo₁₂O₄₀^4– (GeMo₁₂–SiMo₁₂) electrodes built with this PIL demonstrated a combined contribution of the individual POMs resulting in a capacitance of 191 F cm^–3, over nine times larger than bare MWCNT. The PIL dual layer composites also maintained 72% of this capacitance at a fast rate of 2 V s^–1, compared to just over 50% retention for similar electrodes fabricated with PDDA.