超级电容器
材料科学
电容
透射电子显微镜
蚀刻(微加工)
电化学
纳米技术
化学工程
氧化还原
扫描电子显微镜
比表面积
多孔性
电极
X射线光电子能谱
分析化学(期刊)
化学
催化作用
物理化学
冶金
图层(电子)
复合材料
工程类
生物化学
色谱法
作者
Yú Hónɡ,Aimei Gao,Xikun Pang,Zhuoran Ao,Dong Shu,Shengxiang Deng,Fenyun Yi,Chun He,Xiaoping Zhou,Zhenhua Zhu
出处
期刊:ACS applied energy materials
[American Chemical Society]
日期:2020-09-07
卷期号:3 (10): 10192-10201
被引量:21
标识
DOI:10.1021/acsaem.0c01969
摘要
Single-atom Ag-decorated MnO2 hollow microspheres (Ag-MnO2 HMSs) with oxygen vacancies are successfully fabricated via a self-template strategy and redox etching method. The transmission electron microscopy images and nitrogen-sorption analyses reveal that the as-prepared Ag-MnO2 HMSs exhibit a porous peanut-like hollow structure with a large specific surface area (∼240 m2 g–1). High-angle annular dark-field scanning transmission electron microscopy confirms that Ag species exist as isolated single atomic sites. The electrochemical experiments show that the 0.3% Ag-MnO2 HMS electrode delivers high specific capacitance (297.5 F g–1 at 0.3 A g–1), 66.3% higher than that of MnO2 HMSs (178.9 F g–1 at 0.3 A g–1), and excellent cycling stability (88.1% capacitance retention after 9000 cycles). Moreover, the assembled Ag-MnO2 HMSs//AC solid-state asymmetric supercapacitor achieves a high operation voltage of 2.0 V and exhibits a high energy density of 15.9 W h kg–1 at a power density of 250.3 W kg–1. Besides, the device can successfully light up a light-emitting diode. The experimental results demonstrate that an appropriate amount of single-atom Ag in MnO2 HMSs promotes the formation of oxygen vacancies, which can improve the conductivity of MnO2 HMSs and the charge storage at Mn and O sites, thereby improving the capacitance performance of MnO2 HMSs.
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