超级电容器
材料科学
法拉第效率
阳极
钼
掺杂剂
电化学
化学工程
兴奋剂
纳米技术
电极
化学
物理化学
光电子学
冶金
工程类
作者
Njemuwa Nwaji,Getasew Mulualem Zewdie,Juyong Gwak,Hyojin Kang,Lemma Teshome Tufa,Yong Eui Choi,Mahedra Goddati,Hyeyoung Shin,Jaebeom Lee
标识
DOI:10.1016/j.est.2024.110671
摘要
Tuning the electronic structure of single-atom catalysts through dimeric single-atom formation could be an innovative approach to increasing their energy storage activity, but the process of achieving this is challenging. In this study, we designed a simple technique to obtain NiCo single atom dimers (SADs) anchored on N-doped molybdenum carbide (N-Mo2C) through in-situ encapsulation of NiCo into molybdenum polydopamine, followed by annealing with optimal tuning of nitrogen dopant. The NiCo atomic level coordination was confirmed with X-ray absorption spectroscopy. When used as energy storage supercapacitor, The NiCo-SADs showed enhanced specific capacity (1004.8 F g−1 at 1 A g−1), enhanced rate capability (75 %), and exceptional cycling stability (93.6 % with 98.5 % coulombic efficiency) via a dominant capacitive charge storage. The augmented charge storage characteristics are attributed to the collaborative features of the active NiCo constituents acting as electron reservoir for effective adsorption of HO− ion during the electrochemical process. The DFT study showed thermodynamically favorable OH− adsorption between the three metal bridges that promoted redox reaction kinetics and enhanced conductivity for the NiCo-SADs. When using N-Mo2C as the anode to fabricate hybrid supercapacitors, the device exhibits high energy density of 69.69 Wh kg−1 at power density of 8200 W kg−1, respectively and shows excellent long-term cycling stability (93.42 % after 3000 cycles), which affirms the potential of the assembled device for applications in solid state supercapacitors.
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