Fast Ionic Diffusion-Enabled Nanoflake Electrode by Spontaneous Electrochemical Pre-Intercalation for High-Performance Supercapacitor

• Published in: Scientific reports Vol. 3; no. 1; p. 1718
• Main Authors: Mai, Liqiang, Li, Han, Zhao, Yunlong, Xu, Lin, Xu, Xu, Luo, Yanzhu, Zhang, Zhengfei, Ke, Wang, Niu, Chaojiang, Zhang, Qingjie
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 24.04.2013; Nature Publishing Group
• Subjects: 639/301/299; 639/301/299/161; 639/301/357/995; 639/638/549; Adsorption; Capacitance; Cations; Crystal structure; Diffusion; Electrochemistry; Electrodes; Electrolytes; Energy; Humanities and Social Sciences; Hybridization; Intercalation; Laboratories; multidisciplinary; Oxides; Science; Sodium
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/srep01718

Layered intercalation compounds Na x MnO 2 (x = 0.7 and 0.91) nanoflakes have been prepared directly through wet electrochemical process with Na + ions intercalated into MnO 2 interlayers spontaneously. The as-prepared Na x MnO 2 nanoflake based supercapacitors exhibit faster ionic diffusion with enhanced redox peaks, tenfold-higher energy densities up to 110 Wh·kg −1 and higher capacitances over 1000 F·g −1 in aqueous sodium system compared with traditional MnO 2 supercapacitors. Due to the free-standing electrode structure and suitable crystal structure, Na x MnO 2 nanoflake electrodes also maintain outstanding electrochemical stability with capacitance retention up to 99.9% after 1000 cycles. Besides, pre-intercalation effect is further studied to explain this enhanced electrochemical performance. This study indicates that the suitable pre-intercalation is effective to improve the diffusion of electrolyte cations and other electrochemical performance for layered oxides and suggests that the as-obtained nanoflakes are promising materials to achieve the hybridization of both high energy and power density for advanced supercapacitors.