Abstract
Printed flexible energy storage devices such as micro-supercapacitors require high electrochemical performance for practical applications. Here, we report a high volumetric energy density of up to 1.13 × 10−3 Wh cm−3 at a power density of 0.11 W cm−3 by inkjet printing of Fe-doped MnO2 nanosheets inks as active materials on polyimide substrates. The enhancement results from atomic-level substitutional doping of 3d metal ions (Co, Fe, Ni) in sub-nanometer thick 2D MnO2 nanosheets. Substitutional doping introduces new electronic states near the Fermi level, thereby enhancing the electronic conductivity and contributing to the formation of redox-active 3d surface states. Fe-doped MnO2 showed the best performance in terms of specific areal and volumetric capacitance. Our finding suggests that the rational doping at atomic scale shows great promise for achieving high energy and power density flexible energy storage devices.
Original language | English (US) |
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Pages (from-to) | 104306 |
Journal | Nano Energy |
Volume | 68 |
DOIs | |
State | Published - Nov 20 2019 |
Bibliographical note
KAUST Repository Item: Exported on 2020-10-01Acknowledgements: Y.W. acknowledges the financial support of the China Scholarships Council program (CSC, No. 201608340058). Y.Z. acknowledges the financial support from the Natural Science Foundation of Jiangsu Province (BK20170999) and the National Natural Science Foundation of China (21805136). A.T.M. Lenferink and C. Otto from the MCBP group at the University of Twente are acknowledged for the acquisition of the MnO Raman spectra. M. Smithers from MESA+ is acknowledged for the HR-SEM and EDS images.