Wei Qiulong, Jiang Yalong, Qian Xiaoshi, Zhang Liang, Li Qidong, Tan Shuangshuang, Zhao Kangning, Yang Wei, An Qinyou, Guo Jinghua, Mai Liqiang
State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, International School of Materials Science and Engineering, Wuhan University of Technology, Wuhan 430070, China; Department of Materials Science and Engineering, University of California Los Angeles, Los Angeles, CA 90095, USA.
State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, International School of Materials Science and Engineering, Wuhan University of Technology, Wuhan 430070, China.
iScience. 2018 Aug 31;6:212-221. doi: 10.1016/j.isci.2018.07.020. Epub 2018 Jul 26.
Sodium ion capacitors (SICs) are designed to deliver both high energy and power densities at low cost. Electric double-layer capacitive cathodes are typically used in these devices, but they lead to very limited capacity. Herein, we apply a pseudocapacitive layered ferric vanadate (Fe-V-O) as cathode to construct non-aqueous SICs with both high energy and power densities. The Fe-V-O nanosheets cathode displays remarkable rate capability and cycling stability. The pseudocapacitive sodium storage mechanism of Fe-V-O, with over 83% of total capacity from capacitive contribution, is confirmed by kinetics analysis and ex situ characterizations. The capacitive-adsorption mechanism of hard carbon (HC) anode is demonstrated, and it delivers excellent rate capability. Based on as-synthesized materials, the assembled HC//Fe-V-O SIC delivers a maximum energy density of 194 Wh kg and power density of 3,942 W kg. Our work highlights the advantages of pseudocapacitive cathodes for achieving both high energy and power densities in sodium storage devices.
钠离子电容器(SICs)旨在以低成本提供高能量密度和高功率密度。这类器件通常使用双电层电容性阴极,但它们的容量非常有限。在此,我们应用赝电容性层状钒酸铁(Fe-V-O)作为阴极来构建具有高能量密度和高功率密度的非水系SICs。Fe-V-O纳米片阴极表现出卓越的倍率性能和循环稳定性。通过动力学分析和非原位表征证实了Fe-V-O的赝电容性储钠机制,其总容量的83%以上来自电容贡献。证明了硬碳(HC)阳极的电容吸附机制,并且它具有优异的倍率性能。基于合成的材料,组装的HC//Fe-V-O SIC的最大能量密度为194 Wh kg,功率密度为3942 W kg。我们的工作突出了赝电容性阴极在实现储钠器件高能量密度和高功率密度方面的优势。