Direct Chemical Synthesis of MnO2 Nanowhiskers on Transition-Metal Carbide Surfaces for Supercapacitor Applications

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• 作者：Raghavan Baby Rakhi ; Bilal Ahmed ; Dalaver Anjum ; Husam N. Alshareef
• 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：18806-18814
• 全文大小：810K
• 年卷期：0
• ISSN：1944-8252

文摘

Transition-metal carbides (MXenes) are an emerging class of two-dimensional materials with promising electrochemical energy storage performance. Herein, for the first time, by direct chemical synthesis, nanocrystalline ε-MnO₂ whiskers were formed on MXene nanosheet surfaces (ε-MnO₂/Ti₂CT_x and ε-MnO₂/Ti₃C₂T_x) to make nanocomposite electrodes for aqueous pseudocapacitors. The ε-MnO₂ nanowhiskers increase the surface area of the composite electrode and enhance the specific capacitance by nearly 3 orders of magnitude compared to that of pure MXene-based symmetric supercapacitors. Combined with enhanced pseudocapacitance, the fabricated ε-MnO₂/MXene supercapacitors exhibited excellent cycling stability with ∼88% of the initial specific capacitance retained after 10000 cycles which is much higher than pure ε-MnO₂-based supercapacitors (∼74%). The proposed electrode structure capitalizes on the high specific capacitance of MnO₂ and the ability of MXenes to improve conductivity and cycling stability.