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

By Lien Mai, Han Li, Yunlong Zhao, Lin Xu, Xu Xu, Yanzhu Luo, Zheng Zhang, Wang Ke, Chaojiang Niu, Qingjie Zhang. Scientific Reports, 2013

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Layered intercalation compounds NaxMnO2 (x = 0.7 and 0.91) nanoflakes have been prepared directly through wet electrochemical process with Na+ ions intercalated into MnO2 interlayers spontaneously. The as-prepared NaxMnO2 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 MnO2 supercapacitors. Due to the free-standing electrode structure and suitable crystal structure, NaxMnO2 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.

Subfields: Electrical and Electronic Engineering, Electronic, Optical and Magnetic Materials

View Paper: https://www.semanticscholar.org/paper/affe810774e11102940262f1462e15b546da691e