All-Solid-State High-Energy Asymmetric Supercapacitors Enabled by Three-Dimensional Mixed-Valent MnOx Nanospike and Graphene Electrodes

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• 作者：Jie Yang ; Guizhu Li ; Zhenghui Pan ; Meinan Liu ; Yuan Hou ; Yijun Xu ; Hong Deng ; Leimei Sheng ; Xinluo Zhao ; Yongcai Qiu ; Yuegang Zhang
• 刊名：ACS Applied Materials & Interfaces
• 出版年：2015
• 出版时间：October 14, 2015
• 年：2015
• 卷：7
• 期：40
• 页码：22172-22180
• 全文大小：506K
• ISSN：1944-8252

文摘

Three-dimensional (3D) nanostructures enable high-energy storage devices. Here we report a 3D manganese oxide nanospike (NSP) array electrode fabricated by anodization and subsequent electrodeposition. All-solid-state asymmetric supercapacitors were assembled with the 3D Al@Ni@MnO_x NSP as the positive electrode, chemically converted graphene (CCG) as the negative electrode, and Na₂SO₄/poly(vinyl alcohol) (PVA) as the polymer gel electrolyte. Taking advantage of the different potential windows of Al@Ni@MnO_x NSP and CCG electrodes, the asymmetric supercapacitor showed an ideal capacitive behavior with a cell voltage up to 1.8 V, capable of lighting up a red LED indicator (nominal voltage of 1.8 V). The device could deliver an energy density of 23.02 W h kg^鈥? at a current density of 1 A g^鈥?. It could also preserve 96.3% of its initial capacitance at a current density of 2 A g^鈥? after 10000 charging/discharging cycles. The remarkable performance is attributed to the unique 3D NSP array structure that could play an important role in increasing the effective electrode surface area, facilitating electrolyte permeation, and shortening the electron pathway in the active materials.